1
00:00:07,800 --> 00:00:10,840
Speaker 1: If humans ran as many body lengths per second as

2
00:00:10,840 --> 00:00:14,160
Speaker 1: a mite, we generate a sonic boom. What are the

3
00:00:14,240 --> 00:00:18,400
Speaker 1: factors that determine how fast a critter can go zoom?

4
00:00:18,720 --> 00:00:22,720
Speaker 2: Creatures in movies grow too fast. Grelins and aliens just

5
00:00:22,800 --> 00:00:26,279
Speaker 2: aren't plausible. But let's do a thought experiment. Could you

6
00:00:26,360 --> 00:00:29,240
Speaker 2: design a creature to grow as fast as possible?

7
00:00:30,000 --> 00:00:33,320
Speaker 1: Do smaller animals have shorter lives because of the curve

8
00:00:33,400 --> 00:00:36,400
Speaker 1: of space and time? And if they lived long enough,

9
00:00:36,520 --> 00:00:39,400
Speaker 1: would Daniel and Kelly ever get good with rhyme?

10
00:00:40,520 --> 00:00:41,160
Speaker 2: No?

11
00:00:41,159 --> 00:00:43,920
Speaker 1: No from salt.

12
00:00:44,120 --> 00:00:47,080
Speaker 2: But whatever questions keep you up at night, Daniel and

13
00:00:47,159 --> 00:00:49,280
Speaker 2: Kelly's answers will make it all right.

14
00:00:49,680 --> 00:00:54,480
Speaker 1: Welcome to Listener Questions, episode forty four, featuring doctor John Hutchinson.

15
00:01:07,640 --> 00:01:07,840
Speaker 3: Hi.

16
00:01:07,959 --> 00:01:10,240
Speaker 2: I'm Daniel. I'm a particle physicist who likes to think

17
00:01:10,280 --> 00:01:14,000
Speaker 2: about aliens, and I'm still growing in all the wrong directions.

18
00:01:15,360 --> 00:01:19,320
Speaker 1: Same. Hi, I'm Kelly Winersmith. I study parasites and space,

19
00:01:19,360 --> 00:01:23,479
Speaker 1: and I've never been fast. No one has ever said,

20
00:01:23,560 --> 00:01:26,200
Speaker 1: will Kelly break a speed record? The answer is no.

21
00:01:27,040 --> 00:01:30,240
Speaker 2: I'm also not very fast, and my wife she's fit.

22
00:01:30,319 --> 00:01:34,080
Speaker 2: But these of us are speed demons. However, we somehow

23
00:01:34,400 --> 00:01:37,720
Speaker 2: birthed a child who is very athletic and is now

24
00:01:37,760 --> 00:01:41,080
Speaker 2: like running in college, and I don't know what happened.

25
00:01:41,080 --> 00:01:44,240
Speaker 2: Cosmic ray mutations swap at the hospital.

26
00:01:44,360 --> 00:01:50,240
Speaker 1: Sometime biology is really complicated, and life tells us that.

27
00:01:50,280 --> 00:01:53,560
Speaker 2: Exactly will your kid be like you? It depends?

28
00:01:53,800 --> 00:01:58,560
Speaker 1: It depends, And you hope not for their sake. For

29
00:01:58,600 --> 00:02:00,080
Speaker 1: their sake, I.

30
00:02:00,040 --> 00:02:01,800
Speaker 2: Hope they get all the best of you and all

31
00:02:01,800 --> 00:02:02,880
Speaker 2: the best of your partner.

32
00:02:03,080 --> 00:02:03,560
Speaker 1: That's right.

33
00:02:03,640 --> 00:02:07,000
Speaker 2: And today we're going to be marrying our knowledge with

34
00:02:07,040 --> 00:02:09,680
Speaker 2: the knowledge of doctor John Hutchinson, who knows a lot

35
00:02:09,760 --> 00:02:12,440
Speaker 2: more about evolutionary biomechanics than we do.

36
00:02:12,760 --> 00:02:15,520
Speaker 1: So let's waste no time and get John back on

37
00:02:15,560 --> 00:02:19,160
Speaker 1: the show. Doctor John Hutchinson is a professor of evolutionary

38
00:02:19,200 --> 00:02:22,600
Speaker 1: biomechanics and a Fellow of the Royal Society. His research

39
00:02:22,639 --> 00:02:26,240
Speaker 1: straddles the fields of evolutionary biology and biomechanics, with an

40
00:02:26,280 --> 00:02:29,720
Speaker 1: emphasis on how very large animals stand and move and

41
00:02:29,720 --> 00:02:33,160
Speaker 1: how locomotion evolved in different groups of land vertebrates. And

42
00:02:33,200 --> 00:02:35,040
Speaker 1: at the end of this episode, you're no doubt going

43
00:02:35,080 --> 00:02:37,440
Speaker 1: to be thinking how can I get more of John?

44
00:02:37,680 --> 00:02:40,080
Speaker 1: And the answer is you can listen to our April

45
00:02:40,160 --> 00:02:43,640
Speaker 1: twenty ninth, twenty twenty five episode where the title was

46
00:02:43,639 --> 00:02:46,720
Speaker 1: was the Tyrannosaurus Rex Fast or Slow. Because this is

47
00:02:46,800 --> 00:02:49,320
Speaker 1: John's second time on the show, and so you can

48
00:02:49,400 --> 00:02:50,880
Speaker 1: go back and enjoy that episode.

49
00:02:50,960 --> 00:02:53,280
Speaker 3: Welcome back, John, Thank you, great to be back.

50
00:02:53,400 --> 00:02:54,880
Speaker 1: We're excited to have you. We had a ton of

51
00:02:54,919 --> 00:02:55,640
Speaker 1: fun last time.

52
00:02:56,040 --> 00:03:01,360
Speaker 2: Your expertise spans our audience's interest because we're talking about biology,

53
00:03:01,480 --> 00:03:03,799
Speaker 2: since these are critters, but we're talking about the physics

54
00:03:03,840 --> 00:03:06,320
Speaker 2: that makes them move fast or slow. So you're like

55
00:03:06,360 --> 00:03:07,920
Speaker 2: the perfect guest for the podcast.

56
00:03:08,919 --> 00:03:11,120
Speaker 3: Oh, I can't claim to be a physicist, but I

57
00:03:11,280 --> 00:03:14,359
Speaker 3: understand what I need to understand for understanding a bit

58
00:03:14,360 --> 00:03:15,840
Speaker 3: of biology. That's good.

59
00:03:16,200 --> 00:03:18,720
Speaker 1: Well, then let's just jump right in. So our first

60
00:03:18,800 --> 00:03:21,760
Speaker 1: question of the day is from Matt McCain. He's one

61
00:03:21,760 --> 00:03:24,639
Speaker 1: of our Discord moderators. He asked this question, yay, Mat,

62
00:03:24,800 --> 00:03:27,200
Speaker 1: yeay Matt. And he asked this question like a million

63
00:03:27,320 --> 00:03:29,760
Speaker 1: years ago. And every time I pulled up a paper,

64
00:03:29,919 --> 00:03:32,440
Speaker 1: there were loads of equations, and it was in physics

65
00:03:32,480 --> 00:03:35,600
Speaker 1: related journals, and so I kept putting aside and quitting

66
00:03:35,600 --> 00:03:39,040
Speaker 1: on it, and then eventually I realized, why don't I dress.

67
00:03:39,080 --> 00:03:43,720
Speaker 4: John, Hey, Daniel and Kelly, your friendly neighborhood moderator Matt

68
00:03:43,760 --> 00:03:46,320
Speaker 4: here I recently went down a rabbit hole of how

69
00:03:46,400 --> 00:03:49,320
Speaker 4: fast certain critters move, and then that led to a

70
00:03:49,360 --> 00:03:52,720
Speaker 4: cascade of questions. So I heard about the tiger beetle

71
00:03:52,760 --> 00:03:56,120
Speaker 4: moving so fast they can temporarily go blind, like their

72
00:03:56,120 --> 00:03:58,800
Speaker 4: eyes can't take in enough photons to form an image

73
00:03:58,800 --> 00:04:02,160
Speaker 4: while they're cruising along. So that's kind of weird due

74
00:04:02,160 --> 00:04:05,080
Speaker 4: to their tiny size, though bugs can't really scale up,

75
00:04:05,120 --> 00:04:07,560
Speaker 4: but if we did, I was wondering if we could

76
00:04:07,560 --> 00:04:10,560
Speaker 4: compare and figure out what the fastest animal is relative

77
00:04:10,600 --> 00:04:13,760
Speaker 4: to size. I'm not sure if that even is scalable,

78
00:04:13,840 --> 00:04:16,400
Speaker 4: and we often hear trivia about birds and other critters

79
00:04:16,400 --> 00:04:18,280
Speaker 4: being some of the fastest in the world, and then

80
00:04:18,320 --> 00:04:20,960
Speaker 4: that led to me finding out they sometimes measure speed

81
00:04:20,960 --> 00:04:26,680
Speaker 4: in body lengths per second. Currently, the almost unpronounceable Partersotomus

82
00:04:26,839 --> 00:04:29,400
Speaker 4: might is the raining champ at about three hundred and

83
00:04:29,400 --> 00:04:32,160
Speaker 4: two body links per second, which would be like a

84
00:04:32,240 --> 00:04:36,400
Speaker 4: human equivalent running at over thirteen hundred miles per hour.

85
00:04:36,920 --> 00:04:39,880
Speaker 4: That's kind of fast. Coming in at mock one point

86
00:04:39,920 --> 00:04:45,000
Speaker 4: seven sonic boom. Human territory help me out, John, Yeah.

87
00:04:44,960 --> 00:04:47,960
Speaker 3: Well, if I could tackle the tiger beetle first, because

88
00:04:48,000 --> 00:04:49,839
Speaker 3: I think that's an interesting case.

89
00:04:50,200 --> 00:04:50,479
Speaker 1: Great.

90
00:04:50,680 --> 00:04:54,760
Speaker 3: What I think the scientific understanding is that they don't

91
00:04:54,800 --> 00:04:59,159
Speaker 3: go blind if they go too fast, not quite, They're

92
00:05:00,520 --> 00:05:04,159
Speaker 3: to chase down prey. Depends on the contrast of the

93
00:05:04,200 --> 00:05:07,119
Speaker 3: prey to the environment. So if it's like the best case,

94
00:05:07,200 --> 00:05:10,720
Speaker 3: like a black insect on a white background, then they

95
00:05:10,720 --> 00:05:13,360
Speaker 3: can see it better. And as they go faster and faster,

96
00:05:13,720 --> 00:05:19,080
Speaker 3: their contrast blurs. Their visual contrast blurs, so they have

97
00:05:19,160 --> 00:05:22,800
Speaker 3: to stop periodically if the contrast is poor versus how

98
00:05:22,880 --> 00:05:23,800
Speaker 3: quickly they're going.

99
00:05:24,520 --> 00:05:27,039
Speaker 2: Why does their contrast blur? Is this something to do

100
00:05:27,120 --> 00:05:29,760
Speaker 2: with the response of the proteins how quickly they can

101
00:05:29,839 --> 00:05:30,800
Speaker 2: recover this?

102
00:05:30,200 --> 00:05:34,240
Speaker 3: This is a visual limit that their nervous system can

103
00:05:34,279 --> 00:05:39,279
Speaker 3: only process and adjust to the visual information based on

104
00:05:39,320 --> 00:05:42,560
Speaker 3: the contrast. If it's coming through it in good enough

105
00:05:42,640 --> 00:05:44,760
Speaker 3: quality at good enough of a rate.

106
00:05:45,000 --> 00:05:48,360
Speaker 2: But why does the relative velocity of the object change that,

107
00:05:49,040 --> 00:05:51,800
Speaker 2: like if it's moving across your field. I guess it's

108
00:05:51,800 --> 00:05:55,320
Speaker 2: a question of like how quickly the neurons can update.

109
00:05:55,760 --> 00:05:58,919
Speaker 3: Yeah, so I mean if you can imagine a really

110
00:05:59,000 --> 00:06:02,919
Speaker 3: quick movement or or really slow camera, there will be

111
00:06:03,000 --> 00:06:07,440
Speaker 3: blur with that, so you can't really adequately visualize that,

112
00:06:07,680 --> 00:06:11,320
Speaker 3: and so your nervous system's perception of where the object

113
00:06:11,360 --> 00:06:15,839
Speaker 3: actually is in space will be increasingly imprecise visually based

114
00:06:15,839 --> 00:06:18,280
Speaker 3: on how fast the object is.

115
00:06:18,839 --> 00:06:20,600
Speaker 2: Let me just make sure I understand. So you're saying,

116
00:06:21,160 --> 00:06:23,280
Speaker 2: if we think about the eye as a camera, it's

117
00:06:23,320 --> 00:06:26,599
Speaker 2: got a shutter speed, and just like something that's zooming

118
00:06:26,640 --> 00:06:30,359
Speaker 2: through your field faster than the update speed, then the

119
00:06:30,360 --> 00:06:33,720
Speaker 2: shutter speed is going to create an image that's smeared

120
00:06:33,760 --> 00:06:37,880
Speaker 2: across your field because the eye is accumulating data over

121
00:06:37,920 --> 00:06:40,520
Speaker 2: that time period and so it ends up smeared. Is

122
00:06:40,520 --> 00:06:41,799
Speaker 2: that a fair analogy.

123
00:06:42,400 --> 00:06:45,520
Speaker 3: That's my understanding of it. And I don't know exactly

124
00:06:45,600 --> 00:06:50,000
Speaker 3: how the tiger beetles visualize objects, but my understanding is

125
00:06:50,120 --> 00:06:54,440
Speaker 3: that it's really a matter of the contrast of the

126
00:06:54,440 --> 00:06:58,600
Speaker 3: object that is a big, big factor, and their prey contrast.

127
00:06:58,880 --> 00:07:01,280
Speaker 3: How dark the prey is relative to the environment and

128
00:07:01,360 --> 00:07:04,200
Speaker 3: so forth will vary a lot depending on the prey

129
00:07:04,240 --> 00:07:05,040
Speaker 3: and the environment.

130
00:07:05,400 --> 00:07:07,839
Speaker 1: So do they tend to go after really like snazzy,

131
00:07:08,200 --> 00:07:11,440
Speaker 1: brightly colored, flashy prey then to try to make it

132
00:07:11,440 --> 00:07:12,400
Speaker 1: easier to see them.

133
00:07:12,960 --> 00:07:17,320
Speaker 3: That I don't know, and there might be really counterintuitive

134
00:07:17,520 --> 00:07:21,200
Speaker 3: issues like I don't know exactly how tiger beetles see.

135
00:07:21,240 --> 00:07:25,000
Speaker 3: Do they have any spectra of the light spectrum that

136
00:07:25,040 --> 00:07:29,640
Speaker 3: they see differently from us, like ultraviolet or whatever, I

137
00:07:29,680 --> 00:07:35,080
Speaker 3: don't know, Or do their prey respond to light differently visually? Yeah, oh,

138
00:07:35,120 --> 00:07:38,640
Speaker 3: I'm know entomologists. I can't can't answer that question.

139
00:07:39,040 --> 00:07:41,320
Speaker 1: I'm going to go on a flashy food diet. I

140
00:07:41,400 --> 00:07:44,240
Speaker 1: only eat food that is highly contrasting and blings a

141
00:07:44,280 --> 00:07:46,000
Speaker 1: lot relative to the environment.

142
00:07:46,160 --> 00:07:48,160
Speaker 2: I only eat slow food, things that sit on my

143
00:07:48,240 --> 00:07:50,520
Speaker 2: plate and have a very low velocity relative to me.

144
00:07:50,760 --> 00:07:53,640
Speaker 3: Okay, I'm all more ol factory.

145
00:07:54,200 --> 00:07:56,360
Speaker 2: I think the slow food movement means something else.

146
00:07:56,400 --> 00:08:00,560
Speaker 1: But I think all factories probably way to go. You

147
00:08:00,640 --> 00:08:04,440
Speaker 1: might enjoy your food more more than the rest of us.

148
00:08:04,840 --> 00:08:07,280
Speaker 2: I like eating at the old factory spaghetti factory.

149
00:08:08,080 --> 00:08:12,600
Speaker 1: Okay, we've got a bit caught up on the vision thing.

150
00:08:13,200 --> 00:08:15,280
Speaker 1: I have a friend who studies tiger beetles, and he

151
00:08:15,360 --> 00:08:18,800
Speaker 1: tells me that they're the fastest animals on the planet,

152
00:08:19,440 --> 00:08:23,560
Speaker 1: and he's right about most things. But your face suggests

153
00:08:23,560 --> 00:08:25,480
Speaker 1: to me that maybe this isn't one of them.

154
00:08:25,840 --> 00:08:30,640
Speaker 3: Well, they're pretty damn fast, and the person asking the

155
00:08:30,760 --> 00:08:34,240
Speaker 3: question is correct. For their size, they're pretty crazy fast.

156
00:08:34,240 --> 00:08:36,040
Speaker 3: And that's true of a lot of small things. If

157
00:08:36,080 --> 00:08:39,760
Speaker 3: you normalize, if you divide speed by by body length,

158
00:08:40,040 --> 00:08:42,960
Speaker 3: small animals are always going to be fast unless they're

159
00:08:42,960 --> 00:08:46,360
Speaker 3: really slow small animals, like a tick or something like that.

160
00:08:46,679 --> 00:08:48,959
Speaker 1: So does that suggest that's not the best way to

161
00:08:49,000 --> 00:08:52,480
Speaker 1: measure it then, because it's a biases towards small animals.

162
00:08:52,520 --> 00:08:55,679
Speaker 3: Well, I think it reveals something about the fundamental nature

163
00:08:55,720 --> 00:09:01,080
Speaker 3: of speed that speed limits on animals are are very

164
00:09:01,120 --> 00:09:06,320
Speaker 3: different depending on the size. There's fundamentally different physical laws

165
00:09:06,400 --> 00:09:10,240
Speaker 3: if you will that influence how small animals are limited

166
00:09:10,320 --> 00:09:13,080
Speaker 3: in their speed versus how large animals are limited in

167
00:09:13,160 --> 00:09:13,640
Speaker 3: their speed.

168
00:09:14,120 --> 00:09:16,360
Speaker 1: How will do we understand those laws? Is that like

169
00:09:16,440 --> 00:09:18,720
Speaker 1: something that's easily articulated.

170
00:09:18,440 --> 00:09:24,120
Speaker 3: Yes, pretty well, we understand pretty well. The overall gestalt

171
00:09:24,400 --> 00:09:29,480
Speaker 3: of what limits animal speed, So smaller animals, the smaller

172
00:09:29,600 --> 00:09:35,520
Speaker 3: that animals are, the more that the power of their muscles,

173
00:09:35,559 --> 00:09:38,240
Speaker 3: So how much force the muscle can produce and how

174
00:09:38,320 --> 00:09:42,080
Speaker 3: quickly they can produce it, that becomes really limiting on

175
00:09:42,280 --> 00:09:45,720
Speaker 3: speeds They have to have really quick muscle there's a

176
00:09:45,760 --> 00:09:49,400
Speaker 3: big contrast with that and big animals where it's not

177
00:09:49,640 --> 00:09:54,680
Speaker 3: so much the power, like the rate of doing energy

178
00:09:54,760 --> 00:09:57,440
Speaker 3: or work with the muscles. That doesn't matter so much

179
00:09:57,480 --> 00:10:00,960
Speaker 3: as just the amount of force that themuscles can generate

180
00:10:01,520 --> 00:10:04,760
Speaker 3: and the amount of distance those muscles can move the

181
00:10:04,800 --> 00:10:08,240
Speaker 3: body over, which is force. Time's distance is work. That's

182
00:10:08,280 --> 00:10:12,840
Speaker 3: the energy of the animals. So rate is not so

183
00:10:12,920 --> 00:10:16,080
Speaker 3: important for big animals in limiting speed. They don't have

184
00:10:16,120 --> 00:10:19,320
Speaker 3: to produce force very quickly. They have to produce a

185
00:10:19,320 --> 00:10:24,360
Speaker 3: lot of force basically, So gravity ultimately limits big animals

186
00:10:24,360 --> 00:10:27,959
Speaker 3: more than smaller animals. And that's why, for example, it's

187
00:10:28,080 --> 00:10:30,840
Speaker 3: very well known like ants can carry many, many times

188
00:10:30,880 --> 00:10:34,400
Speaker 3: their body weight, and that's because gravity just doesn't limit

189
00:10:34,440 --> 00:10:37,400
Speaker 3: them so much at all. Their strength to weight ratio,

190
00:10:37,440 --> 00:10:41,320
Speaker 3: which is a fundamental aspect of biology, is extremely high.

191
00:10:41,400 --> 00:10:45,040
Speaker 3: And that's true of pretty much all organisms. That the

192
00:10:45,080 --> 00:10:48,679
Speaker 3: smaller they are, the stronger they are relative to their weight.

193
00:10:49,160 --> 00:10:51,720
Speaker 2: And is that just because of geometry, and that the

194
00:10:51,800 --> 00:10:54,840
Speaker 2: strength depends on the cross sectional area of your bones

195
00:10:54,920 --> 00:10:58,880
Speaker 2: and your muscles, and that grows by like length squared,

196
00:10:58,960 --> 00:11:01,800
Speaker 2: whereas your weight depends on your volume, which grows like

197
00:11:01,880 --> 00:11:03,160
Speaker 2: length cubed exactly.

198
00:11:03,240 --> 00:11:07,320
Speaker 3: That's the square cube laws. So that governs a huge

199
00:11:07,360 --> 00:11:12,120
Speaker 3: amount of biology that we can understand how size influences

200
00:11:12,280 --> 00:11:16,640
Speaker 3: organismal biology by understanding how things like length and area

201
00:11:17,480 --> 00:11:20,640
Speaker 3: scale with body weight and how other things change with

202
00:11:20,679 --> 00:11:21,200
Speaker 3: body weight.

203
00:11:21,520 --> 00:11:24,880
Speaker 2: And so if we were like on Mars with lower gravity,

204
00:11:25,040 --> 00:11:27,120
Speaker 2: we might expect like bigger ants.

205
00:11:27,559 --> 00:11:31,920
Speaker 3: Oh so limits on size, Yes, yes, that is true,

206
00:11:32,720 --> 00:11:36,160
Speaker 3: although would depend on other factors like oxygen.

207
00:11:36,720 --> 00:11:39,720
Speaker 2: Right, of course, I wasn't suggesting there literally are huge

208
00:11:39,760 --> 00:11:42,040
Speaker 2: ants on Mars, so I would love that. I guess

209
00:11:42,040 --> 00:11:46,360
Speaker 2: I was just more thinking about like alien environments with

210
00:11:46,559 --> 00:11:49,360
Speaker 2: different gravity, but there would be a different range of

211
00:11:49,400 --> 00:11:51,560
Speaker 2: what you call small or large creatures.

212
00:11:51,600 --> 00:11:55,480
Speaker 3: It sounds like, oh yeah, I mean that's a given. Definitely, definitely,

213
00:11:55,640 --> 00:11:58,040
Speaker 3: at least the potential for that, depending on how long

214
00:11:58,120 --> 00:12:01,240
Speaker 3: those organisms had been there over evolutionary time.

215
00:12:01,720 --> 00:12:05,840
Speaker 1: So if you had two animals that were the same

216
00:12:07,400 --> 00:12:10,160
Speaker 1: kind of the same shape but definitely the same like

217
00:12:10,360 --> 00:12:13,080
Speaker 1: mass or height. Like, so two animals that kind of

218
00:12:13,120 --> 00:12:16,920
Speaker 1: looked like deer, but one was much faster than the other,

219
00:12:17,840 --> 00:12:20,960
Speaker 1: what would be the thing that was different? Would it

220
00:12:21,000 --> 00:12:22,800
Speaker 1: be the kinds of muscles they have, or the way

221
00:12:22,800 --> 00:12:25,600
Speaker 1: they attached to their bones. I didn't completely get that

222
00:12:25,679 --> 00:12:26,160
Speaker 1: in my head.

223
00:12:26,679 --> 00:12:30,080
Speaker 3: Probably the biggest difference would be how muscular they were

224
00:12:30,120 --> 00:12:32,880
Speaker 3: a relative to their size. So they were they really

225
00:12:33,000 --> 00:12:37,920
Speaker 3: really like Usain Bolt, really really jacked, or were they

226
00:12:38,120 --> 00:12:42,480
Speaker 3: built more like a marathon runner. Pick your favorite marathon runner.

227
00:12:42,480 --> 00:12:43,800
Speaker 3: I can't think of one at the moment.

228
00:12:44,360 --> 00:12:47,600
Speaker 1: Okay, So big animals need to have more muscles. And

229
00:12:47,760 --> 00:12:50,040
Speaker 1: if you have two animals that are like tiger beetle

230
00:12:50,200 --> 00:12:53,640
Speaker 1: size and one is faster than the other, the difference

231
00:12:53,640 --> 00:12:56,080
Speaker 1: would be the efficiency of their muscle.

232
00:12:56,200 --> 00:12:58,520
Speaker 3: Was that right? Well, it might be how quick their

233
00:12:58,600 --> 00:13:01,880
Speaker 3: muscle could contract or something like that, something that influences

234
00:13:01,920 --> 00:13:05,360
Speaker 3: their ability to generate a lot of force quickly.

235
00:13:06,080 --> 00:13:09,160
Speaker 1: Okay, And what's the fastest animal you've studied?

236
00:13:10,120 --> 00:13:14,920
Speaker 3: So, I mean, I've studied cheetahs, but not really studying

237
00:13:14,920 --> 00:13:17,880
Speaker 3: them at their top speed. Other people in our lab have.

238
00:13:18,440 --> 00:13:21,480
Speaker 1: That's actually a great segue into another question, which is

239
00:13:21,840 --> 00:13:25,160
Speaker 1: if you're trying to measure maximum speed, how can you

240
00:13:25,200 --> 00:13:27,880
Speaker 1: be sure you're measuring maximum speed? Like, how do you

241
00:13:28,040 --> 00:13:30,960
Speaker 1: get an animal to go as fast as it can

242
00:13:31,040 --> 00:13:32,840
Speaker 1: so that you can make these kinds of measurements in

243
00:13:32,840 --> 00:13:34,640
Speaker 1: the lab, because that sounds kind of complicated.

244
00:13:34,920 --> 00:13:40,160
Speaker 3: Yeah, that's always the fundamental challenge, and that's why model organisms,

245
00:13:40,400 --> 00:13:44,480
Speaker 3: organisms that we can really understand well, like well, humans

246
00:13:44,559 --> 00:13:46,920
Speaker 3: are a great model organism because they can tell us

247
00:13:47,200 --> 00:13:48,840
Speaker 3: what's going on. We can tell them what to do

248
00:13:48,880 --> 00:13:50,920
Speaker 3: and they'll do it, so we can we can get

249
00:13:50,920 --> 00:13:54,440
Speaker 3: a good measurement of human maximal speed and so that's

250
00:13:54,480 --> 00:13:59,120
Speaker 3: around eleven twelve meters per second for the best sprinters.

251
00:13:59,520 --> 00:14:03,000
Speaker 3: But other things have to be cooperative. So you can

252
00:14:03,080 --> 00:14:06,600
Speaker 3: get a dog on a treadmill, a horse on a

253
00:14:06,600 --> 00:14:09,439
Speaker 3: treadmill or something like that and get them to run

254
00:14:09,480 --> 00:14:11,480
Speaker 3: as quickly as they can, either on a treadmill or

255
00:14:11,480 --> 00:14:14,120
Speaker 3: a race course, and there you can be pretty confident

256
00:14:14,320 --> 00:14:17,520
Speaker 3: that because they're trained to race, to go as fast

257
00:14:17,559 --> 00:14:19,960
Speaker 3: as they can more or less, then they're going to

258
00:14:20,000 --> 00:14:24,160
Speaker 3: give you their maximal speed. But if you're studying an elephant,

259
00:14:24,200 --> 00:14:28,040
Speaker 3: as I did, you may not get them to go

260
00:14:28,120 --> 00:14:32,040
Speaker 3: very fast. Motivations are big issue. So I studied elephants

261
00:14:32,040 --> 00:14:34,800
Speaker 3: in zoos starting off and found that they were pretty

262
00:14:34,800 --> 00:14:38,320
Speaker 3: slow in zoos, unsurprisingly, because it's hard to motivate them.

263
00:14:38,360 --> 00:14:40,480
Speaker 3: They don't have a lot of space. So for so

264
00:14:40,520 --> 00:14:43,200
Speaker 3: I went to Thailand. I studied elephants there that are

265
00:14:43,360 --> 00:14:48,880
Speaker 3: used in races periodically, and they were way faster than

266
00:14:49,560 --> 00:14:52,240
Speaker 3: like a western zoo elephants on average.

267
00:14:52,640 --> 00:14:54,640
Speaker 2: So what motivates an elephant? How do they make the

268
00:14:54,680 --> 00:14:55,360
Speaker 2: elephant run?

269
00:14:56,280 --> 00:15:00,360
Speaker 3: It varies, so sometimes cheering for them, sometimes having them

270
00:15:00,840 --> 00:15:05,920
Speaker 3: chase another elephant or run to a friendly elephant. They're

271
00:15:05,960 --> 00:15:08,080
Speaker 3: smart animals. You have to kind of work around them

272
00:15:08,080 --> 00:15:10,880
Speaker 3: and their personality and figure out what will motivate them.

273
00:15:11,080 --> 00:15:15,000
Speaker 2: Elephants respond to cheering like peer pressure will encourage an elephant,

274
00:15:15,200 --> 00:15:15,720
Speaker 2: that's the moment.

275
00:15:15,920 --> 00:15:20,520
Speaker 3: Yeah, they're super smart, super smart social animals. So, and

276
00:15:20,560 --> 00:15:24,040
Speaker 3: they're bonded with their trainers in Thailand because they grow

277
00:15:24,120 --> 00:15:28,400
Speaker 3: up together. Literally, the humans, the mahoots as they're called,

278
00:15:28,480 --> 00:15:32,840
Speaker 3: and the elephants spend their lifetimes growing up together, developing bonds.

279
00:15:33,480 --> 00:15:36,880
Speaker 3: And that's why they were able to motivate their elephants

280
00:15:36,960 --> 00:15:40,080
Speaker 3: very well. So by studying lots of elephants over and

281
00:15:40,120 --> 00:15:42,520
Speaker 3: over and over again, getting them to walk and run

282
00:15:42,600 --> 00:15:44,600
Speaker 3: at different speeds, we're able to again and again and

283
00:15:44,600 --> 00:15:47,320
Speaker 3: again get pretty much the same speed out of all

284
00:15:47,360 --> 00:15:51,840
Speaker 3: the elephants, and that was the fastest ever reliably recorded.

285
00:15:51,560 --> 00:15:54,920
Speaker 2: Assuming that elephants don't have some secret top gear that

286
00:15:54,960 --> 00:15:57,480
Speaker 2: they're just not interested in sharing with us humans.

287
00:15:58,160 --> 00:15:59,920
Speaker 3: Yeah, so then you have to kind of go by

288
00:16:00,320 --> 00:16:04,520
Speaker 3: extraordinary claims, require extraordinary evidence, and so we need some

289
00:16:04,560 --> 00:16:08,440
Speaker 3: sort of evidence of that secret gear. Yeah, that's that's

290
00:16:08,440 --> 00:16:11,840
Speaker 3: special pleading in science or and philosophy of society can't

291
00:16:11,880 --> 00:16:15,240
Speaker 3: do that. You can't just say, oh, they're just holding back.

292
00:16:15,360 --> 00:16:19,400
Speaker 3: They could do themar You need some sort of reason

293
00:16:19,720 --> 00:16:23,320
Speaker 3: for that. But it's definitely true many animals do hold back.

294
00:16:23,640 --> 00:16:26,800
Speaker 3: So and many estimates of speed that are out there

295
00:16:26,800 --> 00:16:31,520
Speaker 3: in the scientific literature are wild guesses at best because

296
00:16:31,560 --> 00:16:35,760
Speaker 3: of the unreliable nature of estimating animal speed. If you

297
00:16:35,840 --> 00:16:39,280
Speaker 3: just watch an animal moving out in nature, you could

298
00:16:39,320 --> 00:16:42,560
Speaker 3: easily be off by fifty one hundred percent in your

299
00:16:42,680 --> 00:16:45,680
Speaker 3: estimate of the speed of the animal because we're not

300
00:16:45,760 --> 00:16:47,280
Speaker 3: great at estimating speeds.

301
00:16:47,680 --> 00:16:52,040
Speaker 2: What about scenarios like horses versus buffalo Right there, the

302
00:16:52,080 --> 00:16:55,440
Speaker 2: buffalo are clearly motivated by survival, especially if there's somebody

303
00:16:55,520 --> 00:16:59,200
Speaker 2: on horseback shooting at them, and the horses are motivated

304
00:16:59,200 --> 00:17:02,520
Speaker 2: by the rider who's faster. In that scenario, buffalo or

305
00:17:02,520 --> 00:17:03,240
Speaker 2: a horse.

306
00:17:03,400 --> 00:17:05,760
Speaker 3: They're going to be pretty close because their size is

307
00:17:05,760 --> 00:17:09,280
Speaker 3: pretty similar. They're pretty similar in terms of musculature. But

308
00:17:09,359 --> 00:17:12,720
Speaker 3: the horse has a slight edge there based on length

309
00:17:12,760 --> 00:17:16,439
Speaker 3: of the legs and lightness of the feet and so forth.

310
00:17:16,480 --> 00:17:20,400
Speaker 3: They are a bit more adapted for running quickly. But bison, buffalo,

311
00:17:20,760 --> 00:17:23,480
Speaker 3: so forth, they can run fast. I mean they're also

312
00:17:24,440 --> 00:17:28,640
Speaker 3: ungulates to hooked mammals, which in general have very lightweight,

313
00:17:29,359 --> 00:17:33,000
Speaker 3: long lens that they're able to move quickly and therefore

314
00:17:33,240 --> 00:17:34,520
Speaker 3: run quickly and efficiently.

315
00:17:35,000 --> 00:17:37,040
Speaker 2: I don't think of a bison as fast because I

316
00:17:37,080 --> 00:17:39,119
Speaker 2: think of them in the cow category and they just

317
00:17:39,400 --> 00:17:43,040
Speaker 2: never really imagine the cow going anywhere quickly. But I've

318
00:17:43,080 --> 00:17:46,080
Speaker 2: seen buffalo run because they have them at Fermilab. You know,

319
00:17:46,080 --> 00:17:48,280
Speaker 2: we only need the underground, and so they have a

320
00:17:48,480 --> 00:17:50,840
Speaker 2: herd of buffalo and yeah, they can move.

321
00:17:51,600 --> 00:17:54,520
Speaker 3: Yeah. Yeah. It's the cow bias that I think is

322
00:17:54,680 --> 00:17:59,800
Speaker 3: making us think of less familiar animals as slow. Yeah.

323
00:18:00,280 --> 00:18:03,480
Speaker 1: So what do we think is the fastest animal? And

324
00:18:03,600 --> 00:18:06,800
Speaker 1: how confident can we be given how bogus some of

325
00:18:06,840 --> 00:18:09,439
Speaker 1: these estimates are that we actually know what animal is

326
00:18:09,440 --> 00:18:10,080
Speaker 1: the fastest?

327
00:18:10,400 --> 00:18:13,440
Speaker 3: Oh, well, the cheetah on land, and that's the key

328
00:18:13,480 --> 00:18:16,920
Speaker 3: thing to qualify on land, the cheata is the fastest.

329
00:18:16,960 --> 00:18:20,040
Speaker 3: There's no question about the prongo or antelope come close.

330
00:18:20,680 --> 00:18:23,960
Speaker 3: But cheetahs have been reliably measured at around sixty five

331
00:18:24,040 --> 00:18:24,720
Speaker 3: miles an hour.

332
00:18:24,920 --> 00:18:26,200
Speaker 1: Yeah, that's pretty impressive, but.

333
00:18:26,160 --> 00:18:28,760
Speaker 2: That's in the metric of like speed relative to the ground,

334
00:18:28,920 --> 00:18:30,879
Speaker 2: not in body lengths per second.

335
00:18:30,960 --> 00:18:35,360
Speaker 3: Yeah, absolute speed is That's what I'm going based on. Yeah.

336
00:18:35,800 --> 00:18:38,639
Speaker 3: But then yeah, things like the might that the question

337
00:18:38,840 --> 00:18:42,199
Speaker 3: asker mentioned. Yeah, I mean, if you go down to

338
00:18:42,359 --> 00:18:46,040
Speaker 3: really tiny size, then body lengths per second is going

339
00:18:46,119 --> 00:18:50,440
Speaker 3: to give you a faster speed relative to body length

340
00:18:50,520 --> 00:18:51,840
Speaker 3: for smaller things.

341
00:18:52,359 --> 00:18:54,879
Speaker 2: And why is the might so fast? Like, why is

342
00:18:54,920 --> 00:18:55,600
Speaker 2: it so mighty?

343
00:18:57,320 --> 00:18:59,760
Speaker 3: I think that might be the wrong question. That maybe

344
00:18:59,840 --> 00:19:02,879
Speaker 3: the matter. It may not matter how fast the might is.

345
00:19:03,160 --> 00:19:05,280
Speaker 3: I mean where the mites need to go. They're not

346
00:19:05,440 --> 00:19:08,719
Speaker 3: yet going long distance. They're not what motivates the might

347
00:19:08,880 --> 00:19:13,400
Speaker 3: avoiding predators that are chasing them in a pursuit kind

348
00:19:13,440 --> 00:19:17,800
Speaker 3: of situation. They're pretty in general. I mean I can't

349
00:19:17,840 --> 00:19:22,320
Speaker 3: speak for all mts, but in general, nights are animals

350
00:19:22,320 --> 00:19:25,360
Speaker 3: that are in hiding a lot of the time and

351
00:19:25,560 --> 00:19:28,080
Speaker 3: They're not going to be running around like a buffalo

352
00:19:28,200 --> 00:19:32,320
Speaker 3: is on a on a grassland. Their environment is completely different,

353
00:19:32,440 --> 00:19:35,960
Speaker 3: much more cluttered. So they're just going from place to

354
00:19:36,000 --> 00:19:38,119
Speaker 3: place short distances. And that's true of a lot of

355
00:19:38,119 --> 00:19:41,280
Speaker 3: small animals that if you watch them, they don't move

356
00:19:41,320 --> 00:19:45,679
Speaker 3: long distances for long periods of time. They use intermittent locomotion.

357
00:19:46,040 --> 00:19:48,240
Speaker 3: And that's the case of the tiger beel. To circle

358
00:19:48,280 --> 00:19:51,080
Speaker 3: back to that is that because of their visual blur,

359
00:19:51,200 --> 00:19:57,240
Speaker 3: they have to stop periodically stop running to re calibrate

360
00:19:57,320 --> 00:20:02,520
Speaker 3: where the prey is by just reducing that velocity based blur.

361
00:20:03,119 --> 00:20:05,840
Speaker 3: And so that's the that's their solutions. They slow down

362
00:20:05,920 --> 00:20:08,720
Speaker 3: or even stop, and lots of small animals do that

363
00:20:08,960 --> 00:20:12,280
Speaker 3: is slow down, stop, check out the environment, and then

364
00:20:12,520 --> 00:20:14,840
Speaker 3: pick off a gun if they if they're moving quickly.

365
00:20:15,280 --> 00:20:18,080
Speaker 1: All right, well, I think it's time to circle back

366
00:20:18,080 --> 00:20:20,399
Speaker 1: to Matt and see what he has to say about

367
00:20:20,400 --> 00:20:21,000
Speaker 1: this answer.

368
00:20:21,640 --> 00:20:24,320
Speaker 4: Oh wow, you guys really brought out the big guns

369
00:20:24,320 --> 00:20:27,560
Speaker 4: for my question. Thank you Kelly Daniel and doctor John

370
00:20:27,640 --> 00:20:31,280
Speaker 4: Hutchinson for answering the questions that have been terrorizing my brain.

371
00:20:31,840 --> 00:20:34,600
Speaker 4: I really was though hoping the tiger beetle gain like

372
00:20:34,720 --> 00:20:39,119
Speaker 4: some dark sunglasses and like a walking stick when zooming around. Unfortunately, though,

373
00:20:39,160 --> 00:20:41,320
Speaker 4: as I was leaning, there's really no scaling for a

374
00:20:41,359 --> 00:20:44,400
Speaker 4: true comparison. And if I think too hard about it, now,

375
00:20:44,520 --> 00:20:48,840
Speaker 4: a giant tiger beetle sporting some dark sunglasses stopping removing

376
00:20:48,880 --> 00:20:51,680
Speaker 4: said sunglasses like the dude on CSI to look around

377
00:20:51,720 --> 00:20:54,480
Speaker 4: for prey sounds kind of terrifying to me. I appreciate

378
00:20:54,560 --> 00:20:56,719
Speaker 4: all the time and effort you all took to do

379
00:20:56,760 --> 00:20:58,879
Speaker 4: this deep dive for me, and I'm gonna give a

380
00:20:58,920 --> 00:21:00,880
Speaker 4: quick plug to come and join and the fun sciencey

381
00:21:00,920 --> 00:21:03,800
Speaker 4: discussions in our discord. This community is truly amazing. We

382
00:21:03,840 --> 00:21:06,320
Speaker 4: could always use more pet pictures. Thanks for everyone for

383
00:21:06,359 --> 00:21:08,480
Speaker 4: being spiffy and awesome see in the discord.

384
00:21:08,840 --> 00:21:10,879
Speaker 1: All right, that was awesome or was there anything else

385
00:21:10,920 --> 00:21:11,760
Speaker 1: you wanted to say on that one?

386
00:21:11,840 --> 00:21:15,960
Speaker 3: John, Well, I'll give a personal interest about speed, and

387
00:21:16,040 --> 00:21:19,520
Speaker 3: that's if you've ever encountered a Huntsman spider like out

388
00:21:19,960 --> 00:21:26,359
Speaker 3: in East Asia, Australia so forth, you will be pretty

389
00:21:26,640 --> 00:21:29,320
Speaker 3: startled by how quickly they can move out phill. These

390
00:21:29,359 --> 00:21:34,439
Speaker 3: are usually pretty sizable spiders. They're pretty freaky looking. If

391
00:21:34,480 --> 00:21:36,960
Speaker 3: you have any sort of a rack and aphobia. They

392
00:21:37,000 --> 00:21:39,280
Speaker 3: got it all. They got the big fang's, long legs,

393
00:21:39,520 --> 00:21:42,800
Speaker 3: flat bodies, often kind of hairy looking, and they can

394
00:21:42,880 --> 00:21:47,160
Speaker 3: move blindingly fast. So I went into a hotel in Taiwan,

395
00:21:47,760 --> 00:21:49,840
Speaker 3: and right away when I checked in, opened a closet

396
00:21:49,880 --> 00:21:54,000
Speaker 3: and out came a huntsman spider sprinting across my room. Ah,

397
00:21:54,040 --> 00:21:55,760
Speaker 3: and I couldn't find it, but I had to go

398
00:21:55,800 --> 00:21:58,399
Speaker 3: out for dinner very shortly thereafterwards, so I had to

399
00:21:58,480 --> 00:22:01,560
Speaker 3: leave it in my room. I'm not cool with sleeping

400
00:22:01,560 --> 00:22:04,440
Speaker 3: with spiders. I'm just not down with that. So luckily

401
00:22:04,880 --> 00:22:06,600
Speaker 3: we made our piece when I got back to the

402
00:22:06,680 --> 00:22:09,320
Speaker 3: room after dinner, and I was able to sleep without

403
00:22:09,440 --> 00:22:12,560
Speaker 3: worrying that there was a huntsman spider there. But yeah,

404
00:22:12,560 --> 00:22:15,560
Speaker 3: they can go three point six meters per second. There's

405
00:22:15,600 --> 00:22:19,199
Speaker 3: the fastest brown huntsman spider. You know, that's a moderate

406
00:22:19,240 --> 00:22:22,760
Speaker 3: speed jog for us for a pretty small animal. The

407
00:22:22,760 --> 00:22:27,800
Speaker 3: brown huntsman Heteropoda servina is the genus and species, so

408
00:22:27,840 --> 00:22:30,720
Speaker 3: if you're interested in those, they are the fastest reliably

409
00:22:30,760 --> 00:22:31,720
Speaker 3: recorded spider.

410
00:22:32,280 --> 00:22:35,160
Speaker 1: I didn't want to know that. I will now live

411
00:22:35,160 --> 00:22:37,680
Speaker 1: in fear. And then are they venomous?

412
00:22:38,040 --> 00:22:41,320
Speaker 3: Mildly. They'll hurt a bit if they bite you, but no,

413
00:22:41,440 --> 00:22:45,800
Speaker 3: they eat bugs and geckos and so forth that their

414
00:22:46,359 --> 00:22:47,680
Speaker 3: venom is more suited to.

415
00:22:48,080 --> 00:22:50,440
Speaker 1: They eat geckos. And so when you said we made

416
00:22:50,440 --> 00:22:53,320
Speaker 1: our piece, does that mean he's now resting in peace?

417
00:22:53,720 --> 00:22:55,960
Speaker 1: Or how did you make peace with the huntsmen?

418
00:22:56,320 --> 00:22:58,240
Speaker 3: Oh? Boy, I don't want to go into the details.

419
00:22:58,640 --> 00:23:21,000
Speaker 1: Yeah, all right, moving on, and we're back, and now

420
00:23:21,000 --> 00:23:24,600
Speaker 1: we're answering a question from Aaron. Here is Aaron's question

421
00:23:24,680 --> 00:23:27,440
Speaker 1: about the limits to how fast an organism can grow.

422
00:23:28,040 --> 00:23:31,200
Speaker 5: Hey, Daniel and Kelly, I'm always frustrated in movies when

423
00:23:31,200 --> 00:23:35,639
Speaker 5: creatures grow too fast, like gremlins or the aliens in

424
00:23:35,680 --> 00:23:38,680
Speaker 5: the Alien movie franchise. They're the size of a puppy

425
00:23:38,960 --> 00:23:41,600
Speaker 5: and then hours later they're the size of a full

426
00:23:41,640 --> 00:23:46,919
Speaker 5: grown person. Seems biologically impossible. I've got no problem suspending disbelief,

427
00:23:47,359 --> 00:23:50,920
Speaker 5: but this does make me wonder what organisms grow the fastest.

428
00:23:51,400 --> 00:23:54,960
Speaker 5: What are the biological, chemical, or whatever limits that define

429
00:23:54,960 --> 00:23:57,560
Speaker 5: and limit the speed of growth. Seems like from an

430
00:23:57,560 --> 00:24:01,959
Speaker 5: evolutionary perspective, growing super fast would be advantageous. Do a fox,

431
00:24:02,119 --> 00:24:04,960
Speaker 5: great white shark, and human being all basically grow at

432
00:24:05,000 --> 00:24:07,600
Speaker 5: the same speed. And if you were designing an alien

433
00:24:07,640 --> 00:24:10,479
Speaker 5: creature to grow as fast as possible, what tweaks at

434
00:24:10,520 --> 00:24:13,240
Speaker 5: the cellular level would you make to promote the fastest

435
00:24:13,240 --> 00:24:17,480
Speaker 5: possible growth and what would the trade offs be? Also,

436
00:24:18,200 --> 00:24:21,600
Speaker 5: do plants share similar growth limits to animals? I know

437
00:24:21,680 --> 00:24:24,160
Speaker 5: kudzu can grow pretty fast.

438
00:24:24,440 --> 00:24:28,040
Speaker 2: Thanks a lot, Thank you Aaron for including aliens.

439
00:24:29,600 --> 00:24:31,359
Speaker 1: All right, where do you want to start with that one? John?

440
00:24:32,040 --> 00:24:35,159
Speaker 3: So with the aliens, I think the quick answer there

441
00:24:35,400 --> 00:24:38,159
Speaker 3: is that they've still got to abide by some of

442
00:24:38,200 --> 00:24:42,720
Speaker 3: the fundamental principles of whatever physiology they have, but their

443
00:24:42,720 --> 00:24:47,600
Speaker 3: physiology could vary, perhaps dramatically from what we have. I mean,

444
00:24:48,160 --> 00:24:51,600
Speaker 3: there were only left to speculate. But there's also the

445
00:24:52,200 --> 00:24:58,399
Speaker 3: fundamental principles of size and growth probably generally hold even

446
00:24:58,720 --> 00:25:04,080
Speaker 3: in alien organism. That growth rate tends to be slower

447
00:25:04,240 --> 00:25:09,000
Speaker 3: in bigger things overall. And yeah, like when I watch

448
00:25:09,080 --> 00:25:12,000
Speaker 3: the movie Alien Romulus, I hope this isn't a spoiler,

449
00:25:12,040 --> 00:25:16,080
Speaker 3: but there's at least one xenomorph, one alien there that

450
00:25:16,520 --> 00:25:19,040
Speaker 3: seems to grow in the space of the two hours

451
00:25:19,040 --> 00:25:23,119
Speaker 3: of the movie from a little thing like a little

452
00:25:23,920 --> 00:25:28,040
Speaker 3: fetus sized thing to something bigger than a human. So yeah,

453
00:25:28,160 --> 00:25:31,000
Speaker 3: I mean that caused a bit of credibility issues for me,

454
00:25:31,119 --> 00:25:35,479
Speaker 3: but hey, it's movie logic and it's alien biology, so

455
00:25:35,800 --> 00:25:38,040
Speaker 3: I mean can give it a benefit of the doubt there.

456
00:25:38,440 --> 00:25:41,159
Speaker 2: So you say the fundamental rule is that bigger things

457
00:25:41,240 --> 00:25:44,800
Speaker 2: grow more slowly. That must be a relative thing, Like

458
00:25:44,840 --> 00:25:47,800
Speaker 2: an elephant adds a smaller percentage of its body weight

459
00:25:47,840 --> 00:25:51,159
Speaker 2: every day or week as it's growing than a smaller

460
00:25:51,200 --> 00:25:54,520
Speaker 2: creature does. Why is that? What's the rule that underlies that?

461
00:25:55,359 --> 00:26:00,000
Speaker 3: Yeah, so that's due to the underlying physiology. Metabolic race

462
00:26:00,720 --> 00:26:04,919
Speaker 3: is the key thing there. That smaller animals have higher

463
00:26:04,920 --> 00:26:10,679
Speaker 3: metabolic rates, so yeah, and that's even true of people,

464
00:26:10,800 --> 00:26:13,560
Speaker 3: Like when we're young, we have pretty high metabolic rates,

465
00:26:13,600 --> 00:26:16,520
Speaker 3: and metaball rates slows down as we get older, and

466
00:26:16,560 --> 00:26:18,960
Speaker 3: that relates to our growth rate. So there's a correlation

467
00:26:19,119 --> 00:26:23,439
Speaker 3: between how quickly you burn energy and how quickly you grow.

468
00:26:23,920 --> 00:26:28,240
Speaker 2: Is that what metabolic rate means? You're converting inputs into energy.

469
00:26:28,800 --> 00:26:35,960
Speaker 3: How you use your internal energy to generate something else,

470
00:26:36,119 --> 00:26:42,240
Speaker 3: to transform your internal energy like ATP molecules into something

471
00:26:42,920 --> 00:26:46,119
Speaker 3: being done to your benefit like growth.

472
00:26:46,880 --> 00:26:49,880
Speaker 2: And why do bigger animals have a slower metabolic rate

473
00:26:49,960 --> 00:26:50,879
Speaker 2: or is that not known?

474
00:26:51,280 --> 00:26:52,440
Speaker 1: It's a bummer either way.

475
00:26:54,720 --> 00:26:59,240
Speaker 3: Bigger animals grow more or have slower metabolic rates because

476
00:26:59,560 --> 00:27:04,640
Speaker 3: again the square cube law that because a growth rate

477
00:27:04,800 --> 00:27:10,680
Speaker 3: depends on area to volume scaling, bigger animals have less

478
00:27:10,720 --> 00:27:14,680
Speaker 3: area relative to their volume, so they can't use energy

479
00:27:14,720 --> 00:27:17,879
Speaker 3: as quickly as a smaller animal can. And yeah, smaller animals,

480
00:27:17,920 --> 00:27:21,240
Speaker 3: because they have more area relative to their volume, are

481
00:27:21,320 --> 00:27:25,400
Speaker 3: shedding heat more quickly or gaining heat more quickly from

482
00:27:25,400 --> 00:27:26,120
Speaker 3: their environment.

483
00:27:26,800 --> 00:27:28,640
Speaker 2: So that seems like an argument that would work for

484
00:27:29,080 --> 00:27:32,280
Speaker 2: like warm blooded animals that spend energy to stay warm.

485
00:27:32,880 --> 00:27:35,240
Speaker 2: What about like a snake or a lizard or something.

486
00:27:35,760 --> 00:27:38,000
Speaker 2: I know that they're using energy to the environment, but

487
00:27:38,000 --> 00:27:39,720
Speaker 2: they're not burning energy to stay warm.

488
00:27:39,840 --> 00:27:43,520
Speaker 3: Right, All organisms burn energy to stay warm if they're alive.

489
00:27:43,760 --> 00:27:50,240
Speaker 3: If they're dead, then then maybe not. But yeah, because

490
00:27:50,840 --> 00:27:54,400
Speaker 3: metabolism is fundamentally a wasteful process. It's not one hundred

491
00:27:54,440 --> 00:27:59,520
Speaker 3: percent efficient. You don't convert your metabolic energy into whatever

492
00:27:59,520 --> 00:28:01,760
Speaker 3: you want to do with it at one hundred percent efficiency.

493
00:28:01,800 --> 00:28:05,000
Speaker 3: There's always heat shed. We have to remember heat and

494
00:28:05,280 --> 00:28:08,600
Speaker 3: heat and biology is just waste, a waste product of

495
00:28:08,960 --> 00:28:11,679
Speaker 3: what's going on. So there's actually a lot of waste,

496
00:28:11,680 --> 00:28:14,640
Speaker 3: a lot of heat. Like muscle tends to be only

497
00:28:14,720 --> 00:28:19,040
Speaker 3: thirty percent efficient. The rest goes away as heat. And

498
00:28:19,160 --> 00:28:22,360
Speaker 3: so even small animals, if they're just sitting there, they're

499
00:28:22,400 --> 00:28:25,920
Speaker 3: burning energy quite a lot of energy just sitting there,

500
00:28:25,960 --> 00:28:28,720
Speaker 3: and not just to stay alive, but to remain warm,

501
00:28:28,840 --> 00:28:32,280
Speaker 3: keep their organs at the right temperature during their physiology.

502
00:28:32,320 --> 00:28:37,159
Speaker 3: But yes, it's true that smaller animals tend to be ectothermic,

503
00:28:37,200 --> 00:28:41,040
Speaker 3: that is, rely more on their external environment to keep

504
00:28:41,040 --> 00:28:45,160
Speaker 3: them warm or be quote unquote cold blooded, whereas larger

505
00:28:45,200 --> 00:28:48,760
Speaker 3: animals tend to be endothermic, produce their own body heat more,

506
00:28:49,240 --> 00:28:52,800
Speaker 3: rely more on that maintain a more constant body temperature,

507
00:28:53,280 --> 00:28:57,680
Speaker 3: whereas ectothermic animals tend to vary their body temperature more

508
00:28:58,080 --> 00:29:02,600
Speaker 3: because of their environment. And those two things endo ectothermy

509
00:29:02,640 --> 00:29:04,720
Speaker 3: are sort of a continuum.

510
00:29:05,000 --> 00:29:09,200
Speaker 1: But it's complicated biology, It's complicated.

511
00:29:09,400 --> 00:29:12,720
Speaker 3: Yeah, the ambient temperature does have a big effect on

512
00:29:12,840 --> 00:29:18,160
Speaker 3: metabolic rate and on growth, especially in ectothermic or cold

513
00:29:18,160 --> 00:29:23,280
Speaker 3: blooded organisms. They rely on the environmental temperature to regulate

514
00:29:23,320 --> 00:29:27,400
Speaker 3: their metabolic rate and therefore it will influence their growth rate.

515
00:29:27,800 --> 00:29:32,040
Speaker 2: Thanks for correcting my naive ninth grade biology knowledge makes

516
00:29:32,040 --> 00:29:35,960
Speaker 2: perfect sense that even if cold blooded animals are not

517
00:29:36,240 --> 00:29:39,680
Speaker 2: trying to regulate their temperature, of course their metabolism is

518
00:29:39,720 --> 00:29:42,560
Speaker 2: subject to the laws of thermodynamics, which means there's waste

519
00:29:42,600 --> 00:29:44,760
Speaker 2: and it produces heat. That makes a lot of sense.

520
00:29:44,800 --> 00:29:48,560
Speaker 3: Please please correct my physics. Please correct my physics at

521
00:29:48,560 --> 00:29:49,160
Speaker 3: any time.

522
00:29:50,280 --> 00:29:52,760
Speaker 2: And so this connects back the original question because this

523
00:29:52,960 --> 00:29:56,680
Speaker 2: was how we were understanding why bigger animals have a

524
00:29:56,720 --> 00:30:00,640
Speaker 2: smaller growth rate per mass. It's because have a slower

525
00:30:00,680 --> 00:30:05,360
Speaker 2: metabolism because they have more volume mean surface area.

526
00:30:06,080 --> 00:30:09,320
Speaker 3: Is that the right connection, Yeah, but it also ties

527
00:30:09,360 --> 00:30:13,760
Speaker 3: into some really interesting other things that are tied into

528
00:30:13,800 --> 00:30:17,360
Speaker 3: metabolic rate. And metabolic rate also depends on having the

529
00:30:17,520 --> 00:30:19,600
Speaker 3: right resources. You need to be able to get enough

530
00:30:19,640 --> 00:30:23,800
Speaker 3: food and so forth. That's very important. But fundamentally, if

531
00:30:23,800 --> 00:30:27,360
Speaker 3: we go down to the cellular level, like the person asked,

532
00:30:27,840 --> 00:30:31,520
Speaker 3: the rate of cell division is a fundamental limit on

533
00:30:31,640 --> 00:30:34,280
Speaker 3: growth rate. You have to be able to do mitosis

534
00:30:34,360 --> 00:30:39,240
Speaker 3: split your cells quickly enough to grow, and that depends

535
00:30:40,040 --> 00:30:44,200
Speaker 3: on the metabolic rate in part, but it also depends

536
00:30:44,320 --> 00:30:48,600
Speaker 3: on stuff that's going on inside the cell and various

537
00:30:48,680 --> 00:30:52,880
Speaker 3: molecular processes of the nucleus. And a fundamental thing, a

538
00:30:52,960 --> 00:30:57,320
Speaker 3: really cool thing that limits growth rate is DNA repair.

539
00:30:57,880 --> 00:30:59,760
Speaker 3: If you think about it, if you're growing your cells

540
00:30:59,760 --> 00:31:04,400
Speaker 3: really really quickly, you'll potentially accumulate more and more errors

541
00:31:04,520 --> 00:31:07,640
Speaker 3: as you're splitting your cells over and over again. And

542
00:31:08,000 --> 00:31:11,960
Speaker 3: if that error accumulates over and over again without getting fixed,

543
00:31:12,480 --> 00:31:17,240
Speaker 3: then you'll get potentially either malformation of the organism or

544
00:31:17,280 --> 00:31:21,120
Speaker 3: in a worst case, cancer, because cancer really is an

545
00:31:21,160 --> 00:31:27,440
Speaker 3: overactive growth rate. It's uncontrolled cell division basically, so growth rate,

546
00:31:27,520 --> 00:31:31,840
Speaker 3: if it's too excessive, could even be cancerous or at

547
00:31:31,880 --> 00:31:35,120
Speaker 3: least lead to malformation. And that depends on the various

548
00:31:35,440 --> 00:31:41,760
Speaker 3: repair mechanisms in cells, DNA repair program, cell death, other

549
00:31:41,840 --> 00:31:44,200
Speaker 3: things that are there to correct for error. Error in

550
00:31:45,240 --> 00:31:48,600
Speaker 3: cells is a very big problem, both in the actual

551
00:31:48,640 --> 00:31:51,840
Speaker 3: longevity of the cells, but also in an evolutionary context.

552
00:31:51,920 --> 00:31:58,120
Speaker 3: There's surely huge selection on repair mechanisms for cells to

553
00:31:58,240 --> 00:32:01,920
Speaker 3: make sure they don't go and just produce lots of

554
00:32:02,240 --> 00:32:05,080
Speaker 3: errors and malformations or cancer or whatnot.

555
00:32:05,440 --> 00:32:08,680
Speaker 1: So we might all be growing much faster if we

556
00:32:08,760 --> 00:32:11,160
Speaker 1: could perfectly replicate and we didn't have to worry about

557
00:32:11,160 --> 00:32:11,760
Speaker 1: getting cancer.

558
00:32:12,320 --> 00:32:15,280
Speaker 3: That's right, if we can control that repair mechanism, that

559
00:32:15,360 --> 00:32:17,960
Speaker 3: could do some wonderful things for a growth rate and

560
00:32:18,640 --> 00:32:20,160
Speaker 3: other things like lifespan.

561
00:32:20,520 --> 00:32:21,840
Speaker 1: It could be twice as big.

562
00:32:22,560 --> 00:32:23,880
Speaker 2: Would you want that?

563
00:32:24,760 --> 00:32:26,360
Speaker 1: I'm just kidding. I don't really want to be twice

564
00:32:26,360 --> 00:32:27,680
Speaker 1: as big. I'm plenty big.

565
00:32:27,720 --> 00:32:31,680
Speaker 2: But it sounds like when you're watching alien xenomorph romulus

566
00:32:31,760 --> 00:32:35,960
Speaker 2: or whatever, your real biology constraint is like, hey, that

567
00:32:36,000 --> 00:32:38,360
Speaker 2: alien should have a lot of cancer given how fast

568
00:32:38,360 --> 00:32:38,880
Speaker 2: it grows.

569
00:32:39,280 --> 00:32:46,080
Speaker 3: Oh, unless it has some super alien correction mechanism, so

570
00:32:46,120 --> 00:32:49,080
Speaker 3: who knows. It could be using silicon as it's rather

571
00:32:49,200 --> 00:32:53,920
Speaker 3: than carbon as it's fundamental molecules, so then it could treat.

572
00:32:53,800 --> 00:32:55,560
Speaker 2: That would be a great twist if we could use

573
00:32:55,680 --> 00:32:58,840
Speaker 2: alien xenomorphs as a way to find a cancer cure. Right, Like,

574
00:32:58,880 --> 00:33:01,320
Speaker 2: we have to have some cool bike chemical technology in them.

575
00:33:01,680 --> 00:33:03,720
Speaker 3: Write it up. There's your movie script.

576
00:33:03,400 --> 00:33:07,280
Speaker 1: Right there, Netflix, call me, that's right.

577
00:33:08,160 --> 00:33:11,560
Speaker 3: Other things that become important to growth rate are also

578
00:33:12,000 --> 00:33:15,080
Speaker 3: parental care. That animals that are cared for more by

579
00:33:15,160 --> 00:33:19,840
Speaker 3: their parents can potentially grow more quickly, especially if they're

580
00:33:19,840 --> 00:33:22,960
Speaker 3: being provided by their parents with lots of high nutrient

581
00:33:23,440 --> 00:33:27,600
Speaker 3: food stuffs, but also reproductive rate will influence growth rate

582
00:33:27,640 --> 00:33:30,080
Speaker 3: that if you need to get to adulthood quickly so

583
00:33:30,120 --> 00:33:34,440
Speaker 3: that you can reproduce yourself and your population quickly, then

584
00:33:34,640 --> 00:33:38,080
Speaker 3: growth rate will need to be adequate. Although that there's

585
00:33:38,120 --> 00:33:40,640
Speaker 3: a trade off with the next thing that we'll talk about,

586
00:33:40,640 --> 00:33:45,520
Speaker 3: which is lifespan. So growth rate, metabolic rate, reproductive rate,

587
00:33:46,240 --> 00:33:50,680
Speaker 3: locomotive speed, all these things are intertwined in interesting ways.

588
00:33:51,240 --> 00:33:54,920
Speaker 1: It depends. Okay, so you can't replicate too quickly because

589
00:33:54,960 --> 00:33:58,719
Speaker 1: you may get cancer if you start growing your bones?

590
00:33:58,760 --> 00:34:01,160
Speaker 1: Are your muscles too fat? Is there ever a trade

591
00:34:01,160 --> 00:34:03,959
Speaker 1: off with like the quality of what you're producing, Like

592
00:34:04,000 --> 00:34:06,600
Speaker 1: if you make bone really quickly or muscle really quickly,

593
00:34:07,080 --> 00:34:08,760
Speaker 1: is it more likely to tear or to break?

594
00:34:08,960 --> 00:34:12,200
Speaker 3: Oh? Definitely. Yeah. So bone is a wonderful example that

595
00:34:12,200 --> 00:34:15,799
Speaker 3: bone takes time to mature. You have to produce like

596
00:34:15,920 --> 00:34:17,680
Speaker 3: our in our leg bones, we have to produce a

597
00:34:17,719 --> 00:34:22,440
Speaker 3: cartilage model first with living cells, and then gradually those

598
00:34:22,480 --> 00:34:26,359
Speaker 3: cells are replaced by mineral that gets laid down by

599
00:34:26,360 --> 00:34:29,440
Speaker 3: other cells. And so it takes time to produce the

600
00:34:29,800 --> 00:34:34,040
Speaker 3: mineral of our bone that forms the supportive network that

601
00:34:34,080 --> 00:34:37,239
Speaker 3: cartilage gradually goes away. And when we go from a

602
00:34:37,239 --> 00:34:42,120
Speaker 3: pretty squishy, flexible, but living structure made of cartilage to

603
00:34:42,360 --> 00:34:46,760
Speaker 3: a structure that's mostly made of non living but very strong, stiff,

604
00:34:46,920 --> 00:34:51,360
Speaker 3: supportive mineral. So yeah, you couldn't lay down a bone

605
00:34:51,719 --> 00:34:55,480
Speaker 3: very very quickly as a mineral substance. You need that

606
00:34:55,640 --> 00:34:57,920
Speaker 3: time to construct the cartilage.

607
00:34:58,280 --> 00:35:01,920
Speaker 2: It's like cheese. You can like a really soft, fresh cheese,

608
00:35:01,960 --> 00:35:04,520
Speaker 2: but you want like a nice hard parbisan like that

609
00:35:04,600 --> 00:35:07,760
Speaker 2: takes years in a an Italian cave, doesn't it.

610
00:35:09,040 --> 00:35:14,240
Speaker 3: Patience pays off. Another thing that's important is different rates

611
00:35:14,280 --> 00:35:19,000
Speaker 3: of growth of organs. So organs will grow at different

612
00:35:19,080 --> 00:35:22,120
Speaker 3: rates depending on what they are and what they need

613
00:35:22,160 --> 00:35:26,480
Speaker 3: to be in the adult organism, and different molecules govern

614
00:35:26,920 --> 00:35:31,160
Speaker 3: the rate of growth. So like liver growth is regulated

615
00:35:31,239 --> 00:35:35,480
Speaker 3: by bile acid flux. So the bile that you know,

616
00:35:35,640 --> 00:35:39,560
Speaker 3: the liver is very well known for using helps regulate

617
00:35:40,120 --> 00:35:43,600
Speaker 3: how quickly the liver grows. And every different organ there

618
00:35:43,600 --> 00:35:46,440
Speaker 3: are different things that regulate it, and the size of

619
00:35:46,480 --> 00:35:49,919
Speaker 3: the organ at different points in the life cycle will

620
00:35:49,960 --> 00:35:53,760
Speaker 3: be relatively different depending on how quickly it's growing.

621
00:35:54,080 --> 00:35:56,560
Speaker 1: I'm always amazed that the liver grows back at all,

622
00:35:56,840 --> 00:35:58,640
Speaker 1: and that they can do like surgeries where you get

623
00:35:58,640 --> 00:36:00,880
Speaker 1: a little bit of somebody's liver. I'd always assume that

624
00:36:00,880 --> 00:36:03,239
Speaker 1: the liver was like a thing that was made and

625
00:36:03,280 --> 00:36:06,880
Speaker 1: then would not grow anymore. But bodies are amazing.

626
00:36:06,920 --> 00:36:10,680
Speaker 3: They sure are. Yeah, And by tweaking those growth rates

627
00:36:10,680 --> 00:36:14,040
Speaker 3: of organs, you can get really interesting changes of organisms.

628
00:36:14,480 --> 00:36:18,080
Speaker 3: So you can get bigger hands or longer limbs or

629
00:36:18,120 --> 00:36:21,280
Speaker 3: whatever by tweaking differential growth of body parts.

630
00:36:21,640 --> 00:36:23,919
Speaker 1: Do we know if any of these rules that we've

631
00:36:23,920 --> 00:36:26,880
Speaker 1: talked about apply to plants as well or is that

632
00:36:26,960 --> 00:36:28,439
Speaker 1: just like a totally different game.

633
00:36:28,560 --> 00:36:31,160
Speaker 3: Oh yeah, a lot of those rules would apply it

634
00:36:31,200 --> 00:36:34,560
Speaker 3: to plants as well, definitely, like the DNA repair stuff,

635
00:36:34,600 --> 00:36:37,600
Speaker 3: metabolic rate, all that stuff. I guess the one thing

636
00:36:37,640 --> 00:36:41,839
Speaker 3: that wouldn't apply is how fast plants can run, because yeah,

637
00:36:42,000 --> 00:36:42,800
Speaker 3: they do things.

638
00:36:42,640 --> 00:36:48,640
Speaker 2: Differently, basically still zero. It also applies to dairy products,

639
00:36:48,680 --> 00:36:51,799
Speaker 2: right If you take, for example, yogurt and you put

640
00:36:51,800 --> 00:36:53,759
Speaker 2: it in milk, it makes more yogurt just the same

641
00:36:53,760 --> 00:36:56,320
Speaker 2: way the liver grows. Here, I'm really leaning on my

642
00:36:56,440 --> 00:36:57,480
Speaker 2: ninth grade biology.

643
00:36:57,680 --> 00:36:58,800
Speaker 1: Are you hungry today?

644
00:36:58,840 --> 00:37:03,440
Speaker 3: Also, tumbleweeds might argue with you in terms of the

645
00:37:03,960 --> 00:37:08,719
Speaker 3: plant locomotion thing, but they're cheating Yeah, they're.

646
00:37:08,520 --> 00:37:13,480
Speaker 1: Cheating, are tumble I thought tumbleweeds were just like dead

647
00:37:14,440 --> 00:37:17,520
Speaker 1: plants that sort of accumulated and then blew across the

648
00:37:18,120 --> 00:37:21,320
Speaker 1: desert or whatever. Are they alive still.

649
00:37:20,719 --> 00:37:23,440
Speaker 3: I'm sure there's something alive in there, like their seeds.

650
00:37:23,440 --> 00:37:26,200
Speaker 3: But I was joking. I mean, I just when you

651
00:37:27,000 --> 00:37:33,160
Speaker 3: mentioned plants and movement, immediately an image of tumbleweeds jumped

652
00:37:33,200 --> 00:37:36,000
Speaker 3: into my mind. And yeah, I mean there are plants

653
00:37:36,000 --> 00:37:38,880
Speaker 3: that move, but just slowly.

654
00:37:39,600 --> 00:37:42,680
Speaker 1: You could like literally tell me almost anything about plants,

655
00:37:42,680 --> 00:37:44,239
Speaker 1: and as long as you had a straight face, I

656
00:37:44,280 --> 00:37:47,440
Speaker 1: would believe it, because plants can do so many things

657
00:37:47,480 --> 00:37:50,120
Speaker 1: that blow my mind. Like, you know, we had an

658
00:37:50,160 --> 00:37:52,440
Speaker 1: episode a while back about a plant that like, if

659
00:37:52,520 --> 00:37:55,160
Speaker 1: you know, if a branch touches the ground again, it

660
00:37:55,200 --> 00:37:57,200
Speaker 1: will root, and then if you cut it, it will

661
00:37:57,200 --> 00:37:59,040
Speaker 1: produce a new tree. And I'm like, no, no, no, no,

662
00:37:59,080 --> 00:38:01,800
Speaker 1: that's not how animals work. They can't be how anything works.

663
00:38:01,800 --> 00:38:05,560
Speaker 1: And anyway, I'm very animal centric. Plants. Plants seem to

664
00:38:05,560 --> 00:38:07,840
Speaker 1: break all the rules that seem seem logical to me.

665
00:38:08,080 --> 00:38:11,440
Speaker 3: Yeah. I try to remain humble as a train zoologist,

666
00:38:11,600 --> 00:38:15,960
Speaker 3: reminding myself that fungi and plants and other non animals

667
00:38:15,960 --> 00:38:18,480
Speaker 3: can do very cool stuff that we shouldn't let our

668
00:38:18,520 --> 00:38:20,360
Speaker 3: animal bias leave us ignorant of.

669
00:38:20,880 --> 00:38:24,520
Speaker 1: Yeah, I'm way less excited about hugging fungi and plants,

670
00:38:24,600 --> 00:38:27,239
Speaker 1: but yeah, they still do some fascinating things. I've got

671
00:38:27,280 --> 00:38:30,319
Speaker 1: one last question about sharks. So you mentioned that when

672
00:38:30,320 --> 00:38:34,280
Speaker 1: we're building bone, that takes a long time, but sharks

673
00:38:34,320 --> 00:38:38,080
Speaker 1: are mostly cartilage instead of bone, So can sharks grow

674
00:38:38,200 --> 00:38:39,560
Speaker 1: much faster than the rest of us.

675
00:38:40,520 --> 00:38:44,520
Speaker 3: I don't know that that's true that sharks can be

676
00:38:44,680 --> 00:38:50,400
Speaker 3: grow faster. I do know of some studies looking into

677
00:38:50,600 --> 00:38:54,800
Speaker 3: sharks not having as much cancer. Yeah, at least some sharks.

678
00:38:54,840 --> 00:38:58,080
Speaker 3: And there's like recently in the news over the past

679
00:38:58,200 --> 00:39:01,360
Speaker 3: decade or so, there's been a lot of interest in

680
00:39:01,800 --> 00:39:05,839
Speaker 3: these greenland sharks that can get pretty big. These are

681
00:39:06,160 --> 00:39:09,640
Speaker 3: sharks that range into kind of arctic waters. They can

682
00:39:09,680 --> 00:39:12,359
Speaker 3: get quite big. But also it's been realized they can

683
00:39:13,080 --> 00:39:15,960
Speaker 3: perhaps live as long as five hundred years or something

684
00:39:16,080 --> 00:39:21,720
Speaker 3: like that. Wow, And presumably they're growing very slowly during

685
00:39:21,760 --> 00:39:27,160
Speaker 3: that time. But also it seems like they and I

686
00:39:27,200 --> 00:39:30,000
Speaker 3: think if I remember correctly, and other sharks just don't

687
00:39:30,040 --> 00:39:30,960
Speaker 3: get a lot of cancer.

688
00:39:31,360 --> 00:39:34,920
Speaker 1: I feel like that would be hard to confirm because

689
00:39:35,040 --> 00:39:37,960
Speaker 1: we just I mean, we don't watch sharks for that long.

690
00:39:38,000 --> 00:39:40,280
Speaker 1: But I guess we've dissected and eaten a lot of sharks,

691
00:39:40,520 --> 00:39:43,239
Speaker 1: so we probably would have seen plenty of cancer if

692
00:39:43,239 --> 00:39:45,200
Speaker 1: they got a lot of cancer. Yeah, I thought you

693
00:39:45,239 --> 00:39:47,360
Speaker 1: were going to tell me that I was wrong about

694
00:39:47,360 --> 00:39:49,960
Speaker 1: sharks being made mostly of cartilage, and I was going

695
00:39:50,000 --> 00:39:52,640
Speaker 1: to be super nearest, but then you said that, no,

696
00:39:52,719 --> 00:39:55,080
Speaker 1: they don't grow that fast. So anyway, big relief for

697
00:39:55,120 --> 00:39:55,479
Speaker 1: me here.

698
00:39:55,680 --> 00:39:59,719
Speaker 3: But also, sharks have calcified cartilage that forms a lot

699
00:39:59,719 --> 00:40:03,000
Speaker 3: of their stiff supportive network, so they do lay down mineral,

700
00:40:04,040 --> 00:40:07,799
Speaker 3: but still it's a lot more living material than in

701
00:40:08,200 --> 00:40:09,759
Speaker 3: a typical bony fish.

702
00:40:09,920 --> 00:40:12,960
Speaker 2: Okay, five hundred yeers is a lot older than the

703
00:40:13,000 --> 00:40:16,400
Speaker 2: oldest parmesan I'm aware of, So in the shark versus

704
00:40:16,480 --> 00:40:19,879
Speaker 2: parmesan competition, it sounds like sharks are winning. For those

705
00:40:19,960 --> 00:40:21,560
Speaker 2: keeping score at home, we.

706
00:40:21,480 --> 00:40:24,319
Speaker 3: Need to crack open some ceramics and Pompeii and see

707
00:40:24,360 --> 00:40:27,920
Speaker 3: if there's like any any cheese still in there.

708
00:40:29,760 --> 00:40:32,040
Speaker 2: And on the cheese topic, I will say that cheese

709
00:40:32,040 --> 00:40:34,600
Speaker 2: are very fast. You ever seen the cheese roll in

710
00:40:34,640 --> 00:40:36,759
Speaker 2: Scotland where they roll a cheese down the hill and

711
00:40:36,840 --> 00:40:39,480
Speaker 2: people roll down trying to chase it. Nobody ever catches

712
00:40:39,520 --> 00:40:40,200
Speaker 2: that cheese.

713
00:40:40,840 --> 00:40:44,080
Speaker 3: Yeah, you win again, gravity.

714
00:40:44,719 --> 00:40:49,080
Speaker 2: Unfortunately, I just want to make sure we're asking John

715
00:40:49,160 --> 00:40:50,640
Speaker 2: questions he hasn't prepared for.

716
00:40:50,920 --> 00:40:55,000
Speaker 3: That's great, great, I've never witnessed the rolling cheese. I

717
00:40:55,000 --> 00:40:56,840
Speaker 3: think I've seen cartoons of it. Maybe it was in

718
00:40:56,840 --> 00:40:58,759
Speaker 3: the Simpsons or something like that. I don't know.

719
00:40:58,960 --> 00:41:03,880
Speaker 1: Yeah, a cultural touch point for sure. Yes, all right, Aaron,

720
00:41:04,000 --> 00:41:04,919
Speaker 1: what did you have to say?

721
00:41:05,360 --> 00:41:08,440
Speaker 5: Hey, Daniel and Kelly, thanks for answering my question about growth.

722
00:41:08,920 --> 00:41:11,280
Speaker 5: I tried not to take it personally when your guests

723
00:41:11,320 --> 00:41:16,000
Speaker 5: claim that quote metabolism is a fundamentally wasteful process. As

724
00:41:16,040 --> 00:41:20,280
Speaker 5: my kids say, stop body shaming. Also, a little digging

725
00:41:20,320 --> 00:41:23,640
Speaker 5: on my own uncovered a somewhat unbelievable fact that a

726
00:41:23,680 --> 00:41:27,280
Speaker 5: blue whale calf can add up to two hundred pounds

727
00:41:27,280 --> 00:41:30,200
Speaker 5: of body weight, which is about the equivalent of one's

728
00:41:30,280 --> 00:41:34,920
Speaker 5: enomorph per day. Let's just hope that DNA repair process

729
00:41:35,120 --> 00:41:36,000
Speaker 5: is keeping up.

730
00:41:36,440 --> 00:41:37,840
Speaker 3: Thanks again, Erin.

731
00:41:57,680 --> 00:41:59,800
Speaker 1: All right, this last question has a little bit of

732
00:42:00,200 --> 00:42:02,319
Speaker 1: than for everyone, a little bit of biology, a little

733
00:42:02,320 --> 00:42:04,560
Speaker 1: bit of physics, So Daniel will step in here too.

734
00:42:04,920 --> 00:42:06,840
Speaker 1: So Rosalin wanted to know.

735
00:42:07,600 --> 00:42:11,279
Speaker 6: I was thinking about the relationship between space and time,

736
00:42:12,200 --> 00:42:17,439
Speaker 6: and I was wondering if there's a correlation between all

737
00:42:17,520 --> 00:42:25,200
Speaker 6: of that and the experience and time scale of creatures. So, like,

738
00:42:25,640 --> 00:42:28,839
Speaker 6: do smaller animals have shorter lives because they experience time

739
00:42:28,880 --> 00:42:31,520
Speaker 6: at a faster pace than those of us who are bigger, taller,

740
00:42:31,560 --> 00:42:34,000
Speaker 6: and we're little away from the impact of space time

741
00:42:34,040 --> 00:42:38,919
Speaker 6: curvature or are they just similar but not at all

742
00:42:39,000 --> 00:42:40,080
Speaker 6: related to each other.

743
00:42:41,000 --> 00:42:44,240
Speaker 1: Thanks, So we're going to have part of this question

744
00:42:44,360 --> 00:42:46,880
Speaker 1: go to Daniel, and then part of this question. I

745
00:42:46,880 --> 00:42:49,640
Speaker 1: would love to know more about how size impacts lifespan.

746
00:42:50,280 --> 00:42:55,160
Speaker 1: So first of all, Daniel, is spacetime curvature impacting the

747
00:42:55,160 --> 00:42:57,000
Speaker 1: lifespan of organisms?

748
00:42:57,239 --> 00:43:01,200
Speaker 2: Absolutely it is, but probably not in a way that

749
00:43:01,200 --> 00:43:05,520
Speaker 2: we can really measure. You know, space time curvature is

750
00:43:05,600 --> 00:43:09,279
Speaker 2: how space responds to mass, and when there's a lot

751
00:43:09,280 --> 00:43:12,520
Speaker 2: of mass or energy density around, clocks tick more slowly.

752
00:43:12,960 --> 00:43:15,280
Speaker 2: So clocks in the surface of the Earth tick slower

753
00:43:15,320 --> 00:43:18,320
Speaker 2: than clocks out in space. Clocks near a black hole

754
00:43:18,440 --> 00:43:21,839
Speaker 2: tick very very slowly. So the fact that we're all

755
00:43:21,880 --> 00:43:25,800
Speaker 2: here on Earth means that are biological clocks tick more slowly,

756
00:43:26,160 --> 00:43:29,400
Speaker 2: and that's also true for the whole universe. Parts of

757
00:43:29,440 --> 00:43:32,719
Speaker 2: the universe that are far from black holes would have

758
00:43:32,840 --> 00:43:36,560
Speaker 2: clocks that tick more times since the Big Bang than

759
00:43:36,680 --> 00:43:39,160
Speaker 2: clocks that are near black holes. And so in that sense,

760
00:43:39,440 --> 00:43:42,640
Speaker 2: even the universe you can't say has a single age.

761
00:43:42,680 --> 00:43:45,880
Speaker 2: It depends on where you are in space. So if

762
00:43:45,920 --> 00:43:48,040
Speaker 2: you have a creature and it has a lot of mass,

763
00:43:48,080 --> 00:43:49,959
Speaker 2: it's a blue whale, there's going to be a little

764
00:43:49,960 --> 00:43:52,759
Speaker 2: bit more energy density there, which means it's clocks will

765
00:43:52,800 --> 00:43:57,480
Speaker 2: tick more slowly. Is that measurable Almost certainly not, because

766
00:43:57,640 --> 00:44:01,600
Speaker 2: the amount of mass necessary to make clocks tick more

767
00:44:01,640 --> 00:44:04,840
Speaker 2: slowly is really large. Even clocks on the surface of

768
00:44:04,840 --> 00:44:08,040
Speaker 2: the Earth, because of the Earth's enorm is mass, tick

769
00:44:08,320 --> 00:44:12,239
Speaker 2: just barely more slowly than clocks in orbit. So even

770
00:44:12,239 --> 00:44:15,240
Speaker 2: a blue whale is not going to measurably affect clocks.

771
00:44:15,280 --> 00:44:16,960
Speaker 2: But technically it does happen.

772
00:44:17,400 --> 00:44:21,040
Speaker 1: So you're saying it experiences more time because its clock

773
00:44:21,200 --> 00:44:24,080
Speaker 1: is ticking more slowly, and therefore it lives longer. Is

774
00:44:24,120 --> 00:44:27,880
Speaker 1: that these when you kept saying clocks tick more slowly,

775
00:44:28,040 --> 00:44:30,400
Speaker 1: I keep thinking, do you mean like their heart beats

776
00:44:30,400 --> 00:44:32,160
Speaker 1: more slowly. But no, you mean like the amount of

777
00:44:32,160 --> 00:44:33,239
Speaker 1: time it's experiencing.

778
00:44:33,680 --> 00:44:36,440
Speaker 2: I mean it's clock beats more slowly from somebody from

779
00:44:36,480 --> 00:44:39,720
Speaker 2: the outside. So we see it living in slow motion,

780
00:44:40,239 --> 00:44:43,319
Speaker 2: so it's younger, right than we would be, and it

781
00:44:43,400 --> 00:44:46,400
Speaker 2: sees our clocks moving at high speed, so it sees

782
00:44:46,440 --> 00:44:50,720
Speaker 2: the rest of the universe as like operating on fast forward,

783
00:44:51,120 --> 00:44:54,200
Speaker 2: So it lives longer according to our clocks because it's

784
00:44:54,239 --> 00:44:56,320
Speaker 2: living in slow motion. Does that make sense?

785
00:44:57,040 --> 00:45:01,960
Speaker 1: Yes, but at such a negligible differ, friends, Yeah, because

786
00:45:02,200 --> 00:45:05,359
Speaker 1: blue whales are huge, but small relative to the size

787
00:45:05,400 --> 00:45:07,120
Speaker 1: of the universe or something, right, that's.

788
00:45:06,960 --> 00:45:09,520
Speaker 2: Right, But if you have aliens who have masses of

789
00:45:09,560 --> 00:45:12,720
Speaker 2: a star or something, then this could be a real factor.

790
00:45:13,160 --> 00:45:15,240
Speaker 3: That's what I was going to go to, because everything

791
00:45:15,320 --> 00:45:19,520
Speaker 3: matters in a xenomorph universe, a frame or reference. We

792
00:45:19,600 --> 00:45:22,560
Speaker 3: always have to take our biology to that. So, yeah,

793
00:45:22,719 --> 00:45:27,279
Speaker 3: a star sized organism would perceive our time as very

794
00:45:27,280 --> 00:45:30,880
Speaker 3: different from the time it was living in and we

795
00:45:30,920 --> 00:45:32,360
Speaker 3: need more science fiction about that.

796
00:45:33,120 --> 00:45:34,160
Speaker 2: We definitely do.

797
00:45:34,360 --> 00:45:37,920
Speaker 1: Yeah. So are you saying then that an alien that

798
00:45:38,040 --> 00:45:39,560
Speaker 1: was so big it was the size of the sun

799
00:45:40,520 --> 00:45:44,839
Speaker 1: would experience time more slowly and thus live longer than

800
00:45:44,880 --> 00:45:45,840
Speaker 1: the rest of us.

801
00:45:46,239 --> 00:45:49,600
Speaker 2: Yes, it would see us die off more quickly because

802
00:45:49,640 --> 00:45:52,160
Speaker 2: our clocks tick faster than its clocks.

803
00:45:52,280 --> 00:45:55,240
Speaker 3: Wow. Yeah, yeah. So there was that Star Trek movie

804
00:45:55,280 --> 00:45:59,200
Speaker 3: where they where they met like some sort of huge

805
00:45:59,239 --> 00:46:02,560
Speaker 3: thing that was or I thought it was God. Remember

806
00:46:02,560 --> 00:46:04,920
Speaker 3: which movie that was, Like it was a Final Frontier

807
00:46:05,080 --> 00:46:08,560
Speaker 3: or something. Oh, anyway, they blew up God, so it

808
00:46:08,640 --> 00:46:09,560
Speaker 3: was all fine in the end.

809
00:46:12,280 --> 00:46:14,080
Speaker 1: I thought Star Trek was supposed to be like the

810
00:46:14,200 --> 00:46:17,680
Speaker 1: nice version of the sci fi worlds where they were

811
00:46:17,800 --> 00:46:18,960
Speaker 1: like nice to other creatures.

812
00:46:19,080 --> 00:46:20,799
Speaker 3: I think it was a naughty god, or thought it

813
00:46:20,840 --> 00:46:23,040
Speaker 3: was a god and it was naughty, so it had

814
00:46:23,080 --> 00:46:25,719
Speaker 3: to get proton torpedoed or whatever they did to it.

815
00:46:26,320 --> 00:46:28,719
Speaker 1: Got it, got what was coming to him. Yeah, all right,

816
00:46:28,760 --> 00:46:31,920
Speaker 1: Well I really like the biology answers because the physics

817
00:46:31,960 --> 00:46:34,640
Speaker 1: answers kind of break my brain. But they're amazing. But

818
00:46:34,719 --> 00:46:38,640
Speaker 1: let's get a different perspective. So, how does size impact

819
00:46:38,719 --> 00:46:42,560
Speaker 1: lifespan when the framing is biology, John.

820
00:46:42,600 --> 00:46:46,360
Speaker 3: I think there it's simpler, which is nice because biology

821
00:46:46,400 --> 00:46:49,600
Speaker 3: is often so messy. Oh maybe it's not simpler, but

822
00:46:49,640 --> 00:46:54,440
Speaker 3: it's simple. There's a direct relationship between size and lifespan

823
00:46:54,600 --> 00:46:59,640
Speaker 3: in organisms. Generally speaking, bigger things live longer, and growth

824
00:46:59,680 --> 00:47:03,279
Speaker 3: rate is involved there, metabolic rate is involved there, all

825
00:47:03,320 --> 00:47:07,320
Speaker 3: this stuff that we talked about earlier. So bigger things

826
00:47:07,360 --> 00:47:10,560
Speaker 3: take longer to become big, but still they can get

827
00:47:10,600 --> 00:47:13,400
Speaker 3: bigger as long as they have enough resources to do so.

828
00:47:14,560 --> 00:47:17,680
Speaker 3: And that's basically it. That we don't see a lot

829
00:47:17,719 --> 00:47:20,239
Speaker 3: of small things at all that live very long. If

830
00:47:20,280 --> 00:47:24,120
Speaker 3: you think about a mouse, it's lucky to live maybe

831
00:47:24,160 --> 00:47:27,320
Speaker 3: a year. I don't know if kids have ant farms anymore.

832
00:47:27,360 --> 00:47:30,719
Speaker 1: Do they I don't see them flying off the shelves

833
00:47:30,760 --> 00:47:34,759
Speaker 1: at science museums, but I still see them sold at

834
00:47:34,800 --> 00:47:35,640
Speaker 1: science museums.

835
00:47:35,760 --> 00:47:38,840
Speaker 3: I really, I really have deep hope that kids still

836
00:47:38,920 --> 00:47:43,080
Speaker 3: like ant farms, and maybe like them more than YouTube

837
00:47:43,560 --> 00:47:46,040
Speaker 3: or TikTok. But anyway, I mean, if you have an

838
00:47:46,080 --> 00:47:50,040
Speaker 3: ant farm, you'll notice that ants die pretty quickly, and

839
00:47:50,320 --> 00:47:52,480
Speaker 3: other small things die quickly, and if we go down

840
00:47:52,520 --> 00:47:55,400
Speaker 3: to the bacteria level or they're dropping dead like crazy.

841
00:47:56,480 --> 00:48:00,840
Speaker 3: So there's a very strong relationship between si in lifespan

842
00:48:01,520 --> 00:48:02,600
Speaker 3: across biology.

843
00:48:02,880 --> 00:48:06,200
Speaker 2: And I remember hearing this sort of simplistic explanation that

844
00:48:06,280 --> 00:48:09,640
Speaker 2: it was again about metabolism, that larger animals have a

845
00:48:09,640 --> 00:48:13,520
Speaker 2: slower metabolism and a slower heart rate, and that mice

846
00:48:13,560 --> 00:48:16,239
Speaker 2: and elephants live the same number of heart beats, but

847
00:48:16,320 --> 00:48:19,480
Speaker 2: that mice just have their hearts beating faster and so

848
00:48:20,080 --> 00:48:23,160
Speaker 2: fewer ticks on the clock. Is that true or is

849
00:48:23,200 --> 00:48:24,120
Speaker 2: my biology're wrong?

850
00:48:24,640 --> 00:48:27,759
Speaker 3: I think the heart rate thing is very very very

851
00:48:27,880 --> 00:48:31,319
Speaker 3: coarsely true, and that would only apply to organisms that

852
00:48:31,400 --> 00:48:33,600
Speaker 3: have hearts, But I mean that applies to a lot

853
00:48:33,640 --> 00:48:38,560
Speaker 3: of animals. But yeah, I mean growth rate, metabolic rate,

854
00:48:38,840 --> 00:48:42,239
Speaker 3: all that stuff is tied into lifespan pretty tightly. But

855
00:48:42,480 --> 00:48:46,040
Speaker 3: a neat thing that ties into this kind of concept

856
00:48:46,040 --> 00:48:52,279
Speaker 3: of biological time is that small organisms are vulnerable, so

857
00:48:52,400 --> 00:48:55,799
Speaker 3: they tend to have high metabolic rates so they can

858
00:48:55,960 --> 00:48:58,120
Speaker 3: get to a size where they're able to do all

859
00:48:58,160 --> 00:49:01,600
Speaker 3: their adult stuff quickly enough. And that's that relationship of

860
00:49:02,239 --> 00:49:06,720
Speaker 3: size and vulnerability and metabolic rate has evolved. There's selection

861
00:49:07,280 --> 00:49:10,400
Speaker 3: for small things to have high metabolic rates and grow quickly,

862
00:49:11,280 --> 00:49:16,160
Speaker 3: and also there's selection for lifespan to be short, because

863
00:49:16,719 --> 00:49:20,800
Speaker 3: if lifespan is shorter, then organisms can reproduce themselves more quickly.

864
00:49:21,480 --> 00:49:24,759
Speaker 3: The greater your size is, it's probably likely that your

865
00:49:24,920 --> 00:49:28,719
Speaker 3: reproductive rate is going to be slower, otherwise the Earth

866
00:49:28,760 --> 00:49:36,920
Speaker 3: would be covered in whales. So there is again this

867
00:49:37,440 --> 00:49:41,800
Speaker 3: correlation between growth rate, reproductive rate, metabolic rate, and then

868
00:49:42,120 --> 00:49:44,600
Speaker 3: size and lifespan. These things are all tied together and

869
00:49:44,600 --> 00:49:48,680
Speaker 3: then over deep time, over evolution, there are trade offs

870
00:49:48,760 --> 00:49:53,319
Speaker 3: that things that are big go extinct more often and

871
00:49:53,480 --> 00:49:58,399
Speaker 3: speciate create new species less often. So as long as

872
00:49:58,400 --> 00:50:02,480
Speaker 3: the environment is pretty stable, big things do okay. There

873
00:50:02,520 --> 00:50:05,879
Speaker 3: tends to be an increase in the number of big

874
00:50:05,920 --> 00:50:09,680
Speaker 3: bodied adult species over time, But as soon as the

875
00:50:09,760 --> 00:50:13,200
Speaker 3: environment changes, kaboom, they go extinct. And that's why we

876
00:50:13,239 --> 00:50:18,640
Speaker 3: see these mass extinction pulses is because of especially rapid

877
00:50:18,840 --> 00:50:23,319
Speaker 3: environmental change is something that big organisms cannot adapt to.

878
00:50:23,440 --> 00:50:27,000
Speaker 3: They go extinct more quickly, they speciate more slowly, and

879
00:50:27,160 --> 00:50:32,520
Speaker 3: therefore there are less big things in a rapidly changing environment,

880
00:50:33,239 --> 00:50:36,480
Speaker 3: and mass extinctions tend to hit the bigger things harder.

881
00:50:37,040 --> 00:50:39,319
Speaker 2: What a cool experiment we could do to test that,

882
00:50:39,360 --> 00:50:42,480
Speaker 2: which is like land on a bunch of exoplanets and

883
00:50:42,640 --> 00:50:46,600
Speaker 2: understand the relative stability of those ecosystems and see if

884
00:50:46,640 --> 00:50:50,120
Speaker 2: the ones with more stable ecosystems really do have more

885
00:50:50,239 --> 00:50:52,200
Speaker 2: big land animals. That would be crazy.

886
00:50:52,680 --> 00:50:55,200
Speaker 3: Unfortunately, to bring us back to reality, we're doing that

887
00:50:55,239 --> 00:50:58,239
Speaker 3: experiment right now with climate change in a way that's

888
00:50:58,280 --> 00:51:03,680
Speaker 3: never happened before. Even the asteroid that hit Earth, it

889
00:51:03,719 --> 00:51:06,439
Speaker 3: did its share of devastation sixty six million years ago,

890
00:51:06,520 --> 00:51:09,919
Speaker 3: wiping out the Mesozoic dinosaurs and many other things. There

891
00:51:10,040 --> 00:51:14,480
Speaker 3: was clear size selection going on, but some of the

892
00:51:14,560 --> 00:51:18,480
Speaker 3: extinction patterns happened over thousands of years, whereas right now

893
00:51:18,520 --> 00:51:21,040
Speaker 3: the stuff we're doing over the scale of decades is

894
00:51:21,840 --> 00:51:24,839
Speaker 3: pretty unprecedented in terms of extinction, and we're having a

895
00:51:25,040 --> 00:51:29,400
Speaker 3: huge bias toward getting rid of big things because of

896
00:51:29,440 --> 00:51:33,280
Speaker 3: loss of habitat and hunting and so on and so forth.

897
00:51:33,360 --> 00:51:37,520
Speaker 3: That always hits the big things quicker. And that's followed

898
00:51:37,560 --> 00:51:40,320
Speaker 3: on from an ice age just you know, ten thousand

899
00:51:40,400 --> 00:51:43,799
Speaker 3: years ago that again wiped out a lot of the megafauna.

900
00:51:44,239 --> 00:51:46,520
Speaker 3: So yeah, that's our experiment.

901
00:51:47,200 --> 00:51:49,759
Speaker 2: It's hard for ecosystems to respond. And the timescale of

902
00:51:49,800 --> 00:51:53,160
Speaker 2: like a parmesan rather than like geological timescales.

903
00:51:53,680 --> 00:51:57,920
Speaker 3: Yes, yes, again, bringing back to the cheese frame of reference.

904
00:51:59,040 --> 00:52:01,759
Speaker 3: Excit right, we got the xenomore frame of reference and

905
00:52:01,800 --> 00:52:03,839
Speaker 3: the Cheese frame of reference and that's all you need

906
00:52:04,000 --> 00:52:04,800
Speaker 3: for our podcast.

907
00:52:05,960 --> 00:52:08,600
Speaker 1: That's great. We got the two important frames of reference.

908
00:52:08,680 --> 00:52:11,400
Speaker 2: And I have the mental image of an ocean stocked

909
00:52:11,520 --> 00:52:15,120
Speaker 2: filled with whales, overflowing with whales, all of them eating

910
00:52:15,120 --> 00:52:16,080
Speaker 2: a wheel of parmesan.

911
00:52:16,480 --> 00:52:18,799
Speaker 3: Okay, I thought you'd bring the cheese in there. That's great.

912
00:52:20,719 --> 00:52:22,239
Speaker 2: I'm nothing if not predictable.

913
00:52:25,520 --> 00:52:28,439
Speaker 1: Before we go to Rosalind, do you want to tell

914
00:52:28,520 --> 00:52:29,920
Speaker 1: us what you've been up to and give us a

915
00:52:30,000 --> 00:52:32,759
Speaker 1: quick update on the cool stuff you've been doing since

916
00:52:32,760 --> 00:52:33,520
Speaker 1: we last chatted.

917
00:52:34,239 --> 00:52:37,640
Speaker 3: What have I been doing. I've been studying crocodiles a lot,

918
00:52:38,400 --> 00:52:42,520
Speaker 3: both living ones and extinct ones. How they move, how

919
00:52:42,520 --> 00:52:45,399
Speaker 3: their movement has evolved. That's a big focus of mine

920
00:52:45,600 --> 00:52:50,920
Speaker 3: lately with various postdoctoral researchers and PhD students and master

921
00:52:51,000 --> 00:52:53,880
Speaker 3: students and undergrads. So that's been a lot of fun

922
00:52:53,920 --> 00:52:57,480
Speaker 3: trying to unravel the history of crocodiles and how they

923
00:52:57,520 --> 00:53:02,120
Speaker 3: move in more detail, because they start off as wonderful, small,

924
00:53:02,239 --> 00:53:05,919
Speaker 3: kind of cat sized, quick animals and then evolved into

925
00:53:06,000 --> 00:53:10,319
Speaker 3: the diversity of different forms that ultimately got wiped out

926
00:53:10,320 --> 00:53:12,600
Speaker 3: by that mass extinction at the end of the Cretaceous

927
00:53:13,480 --> 00:53:16,879
Speaker 3: leaving just the crocodiles and alligators that we're familiar with.

928
00:53:17,480 --> 00:53:19,680
Speaker 3: So there was a great diversity of crocodiles back in

929
00:53:19,719 --> 00:53:23,640
Speaker 3: the Mesozoic that we can't really appreciate from a modern

930
00:53:24,000 --> 00:53:27,759
Speaker 3: perspective of the twenty five twenty eight species of all

931
00:53:28,120 --> 00:53:32,520
Speaker 3: fairly similar crocodilians, whereas about two hundred and thirty million

932
00:53:32,560 --> 00:53:36,440
Speaker 3: years ago there were these really amazing more mammal like crocodiles,

933
00:53:36,520 --> 00:53:40,480
Speaker 3: and then later things like whale like crocodiles, and yeah,

934
00:53:40,760 --> 00:53:45,320
Speaker 3: crazy kinds of ecologies and body plans and locomotive styles

935
00:53:45,440 --> 00:53:49,560
Speaker 3: of crocodiles over there over their heyday. So that's I'm

936
00:53:49,560 --> 00:53:53,480
Speaker 3: doing a lot about that. That's keeping me very busy.

937
00:53:54,040 --> 00:53:57,919
Speaker 1: Cool. You know, crocodiles also have very fascinating parasites which

938
00:53:57,920 --> 00:54:01,040
Speaker 1: you can, you know, keep your eyes open for. Haley

939
00:54:01,120 --> 00:54:05,319
Speaker 1: Dutton recently described a new parasite from the eye of

940
00:54:05,360 --> 00:54:08,160
Speaker 1: a crocodile, and she named it. She got to name

941
00:54:08,200 --> 00:54:10,520
Speaker 1: the whole genus and she named it later gator, which

942
00:54:10,560 --> 00:54:14,400
Speaker 1: I thought was fun and rolls off the tongue. So anyway,

943
00:54:14,640 --> 00:54:17,239
Speaker 1: keep your eyes open for fun parasites, including parasites on

944
00:54:17,280 --> 00:54:17,760
Speaker 1: their eyes.

945
00:54:18,040 --> 00:54:20,839
Speaker 3: That's why they have crocodile tears. It's all the parasites.

946
00:54:23,000 --> 00:54:26,800
Speaker 1: Yeah, perhaps, do you make sure that their like mouths

947
00:54:26,840 --> 00:54:30,919
Speaker 1: are held shut in some way before you are measuring them?

948
00:54:31,040 --> 00:54:31,719
Speaker 5: Or oh?

949
00:54:31,840 --> 00:54:35,040
Speaker 3: Yeah. So when I work with live crocodiles, which I've

950
00:54:35,040 --> 00:54:38,880
Speaker 3: done a fair amount for health and safety reasons, you

951
00:54:38,960 --> 00:54:42,000
Speaker 3: do have to worry about the bitey end and the tail.

952
00:54:42,760 --> 00:54:44,920
Speaker 3: The tail end too, because the tail's also a weapon,

953
00:54:45,200 --> 00:54:50,560
Speaker 3: but the bidy end's worse and Luckily, wild crocodile jaw

954
00:54:51,040 --> 00:54:53,680
Speaker 3: closing muscles are very strong. If you ever look at

955
00:54:53,719 --> 00:54:56,160
Speaker 3: the back of the head of a crocodile, it looks

956
00:54:56,200 --> 00:54:59,480
Speaker 3: like they have fatty jowls, especially if the crocodile is

957
00:54:59,520 --> 00:55:02,879
Speaker 3: lying down. That's not fat, that's not jowls. That's jaw

958
00:55:02,920 --> 00:55:07,000
Speaker 3: closing muscle. Wow, it's real meaty muscle. And so they

959
00:55:07,080 --> 00:55:11,080
Speaker 3: have the greatest bite for us of organisms in absolute terms.

960
00:55:11,480 --> 00:55:15,200
Speaker 3: They can bite extremely hard, but their jaw opening muscles

961
00:55:15,200 --> 00:55:19,600
Speaker 3: are weak. So if you close a crocodile's mouth, it's

962
00:55:19,640 --> 00:55:23,160
Speaker 3: not so good at opening the mouth again, So what

963
00:55:23,200 --> 00:55:26,719
Speaker 3: we do is close the crocodile's mouth by restraining it

964
00:55:26,800 --> 00:55:30,120
Speaker 3: and then put electrical tape around the mouth. And that's

965
00:55:30,239 --> 00:55:34,080
Speaker 3: enough to secure the snout shut so it can't bite anyone.

966
00:55:34,160 --> 00:55:38,640
Speaker 3: They still have teeth that stick out, so the jaws

967
00:55:38,640 --> 00:55:40,360
Speaker 3: still have sharp bets on the end that you have

968
00:55:40,400 --> 00:55:42,520
Speaker 3: to watch for. But still that's a lot, a lot

969
00:55:42,560 --> 00:55:44,880
Speaker 3: better than getting bitten by one, because even a small

970
00:55:44,880 --> 00:55:46,680
Speaker 3: crocodile can really hurt you.

971
00:55:47,160 --> 00:55:49,960
Speaker 1: All Right, Well, that's intense, and hopefully you'll come back

972
00:55:50,000 --> 00:55:51,799
Speaker 1: on the show in the future and tell us more

973
00:55:51,880 --> 00:55:53,600
Speaker 1: about what you've learned about crocodiles.

974
00:55:53,719 --> 00:55:55,280
Speaker 3: I'd love to Awesome.

975
00:55:55,680 --> 00:55:57,880
Speaker 1: We're gonna send this answer to Rosalind and see what

976
00:55:57,960 --> 00:55:58,560
Speaker 1: she had to say.

977
00:55:59,120 --> 00:56:01,799
Speaker 6: Daniel Kelly, thanks for answering my question. It makes a

978
00:56:01,800 --> 00:56:03,640
Speaker 6: lot of sense. It has more to do with biology

979
00:56:03,680 --> 00:56:06,160
Speaker 6: than space and time. I was up very late that

980
00:56:06,280 --> 00:56:09,440
Speaker 6: night reading a lot of ancient philosophers and they had

981
00:56:09,440 --> 00:56:12,160
Speaker 6: some really big ideas about the universe and nature, and

982
00:56:12,680 --> 00:56:15,080
Speaker 6: it just kind of got me into thinking. Thanks for

983
00:56:15,120 --> 00:56:17,280
Speaker 6: bringing it back a little bit closer to home. Biology

984
00:56:17,320 --> 00:56:18,880
Speaker 6: makes sense. I appreciate you.

985
00:56:25,880 --> 00:56:28,279
Speaker 2: Thanks everybody for listening. Please go and do us a

986
00:56:28,320 --> 00:56:31,560
Speaker 2: favor and rate the show on whatever podcast app you're using.

987
00:56:31,640 --> 00:56:33,239
Speaker 2: It really helps people find us.

988
00:56:33,760 --> 00:56:37,680
Speaker 1: Daniel and Kelly's Extraordinary Universe is edited by the amazing

989
00:56:37,719 --> 00:56:38,440
Speaker 1: Matt Kesselman.

990
00:56:38,680 --> 00:56:41,920
Speaker 2: He really is a wizard. You can also find us

991
00:56:42,040 --> 00:56:47,120
Speaker 2: online on Blue Sky, Instagram, and x D and K Universe.

992
00:56:47,160 --> 00:56:48,399
Speaker 2: Come engage with us.

993
00:56:48,640 --> 00:56:51,360
Speaker 1: You can email us at questions at Daniel and Kelly

994
00:56:51,440 --> 00:56:53,680
Speaker 1: dot org. We really do want to hear.

995
00:56:53,560 --> 00:56:56,200
Speaker 2: From you, and you can find our website www dot

996
00:56:56,320 --> 00:57:00,160
Speaker 2: danieland Kelly dot org, where you'll also find an invitation

997
00:57:00,280 --> 00:57:03,680
Speaker 2: to join our discord where everybody comes and talks about

998
00:57:03,680 --> 00:57:04,920
Speaker 2: the amazing universe.

999
00:57:05,200 --> 00:57:09,200
Speaker 1: And we also have the most amazing moderators. This is

1000
00:57:09,200 --> 00:57:11,759
Speaker 1: an iHeart podcast. Thanks for joining us.