1 00:00:03,040 --> 00:00:05,840 Speaker 1: Welcome to Stuff to Blow your Mind from how Stuff 2 00:00:05,840 --> 00:00:14,160 Speaker 1: Works dot com. Hey you welcome to Stuff to Blow 3 00:00:14,200 --> 00:00:17,160 Speaker 1: your mind. My name is Robert Lamb and I'm Joe McCormick. 4 00:00:17,640 --> 00:00:22,680 Speaker 1: And today we're talking about bipeds, bipedalism. Uh. And this 5 00:00:22,760 --> 00:00:25,000 Speaker 1: is a this is a topic that I was just 6 00:00:25,079 --> 00:00:27,840 Speaker 1: kind of rattling around my brain the other day because 7 00:00:28,440 --> 00:00:31,400 Speaker 1: for most of us, walking is just kind of every day, right, 8 00:00:31,440 --> 00:00:33,839 Speaker 1: you run a little bit, uh, maybe you hop a 9 00:00:33,920 --> 00:00:36,640 Speaker 1: little bit. It's of course involved multiple times and mammals. 10 00:00:36,680 --> 00:00:40,440 Speaker 1: You have macropods, kangaroo rats in my spring hair hopping, 11 00:00:40,440 --> 00:00:43,480 Speaker 1: my pangolins, and of course homing a apes um much 12 00:00:44,200 --> 00:00:47,519 Speaker 1: which includes ourselves and sometimes scientists, you know, make the 13 00:00:47,560 --> 00:00:51,920 Speaker 1: distinction between facultative and obligate bypeds, though this isn't a 14 00:00:52,080 --> 00:00:55,600 Speaker 1: standard distinction, suffice to say they're creatures such as the 15 00:00:55,680 --> 00:00:59,600 Speaker 1: human flightless birds, and to draw on a prehistoric example, 16 00:00:59,680 --> 00:01:02,720 Speaker 1: the t w rex, that have no real alternative to 17 00:01:02,840 --> 00:01:06,720 Speaker 1: bipedal movement. I mean, I can crab walk around, Yeah, 18 00:01:06,760 --> 00:01:09,120 Speaker 1: I wouldn't. If if you're crab walking, you're still bipedal 19 00:01:09,360 --> 00:01:12,000 Speaker 1: unless you can grow some crab legs. It depends which 20 00:01:12,080 --> 00:01:13,479 Speaker 1: version of the crab walk. Are you're talking, you're talking 21 00:01:13,480 --> 00:01:15,720 Speaker 1: about where you're I'm talking where you know, you lean 22 00:01:15,840 --> 00:01:17,880 Speaker 1: back and you go on all four your belly up 23 00:01:17,920 --> 00:01:20,040 Speaker 1: in the air. Because there's also the Zoidberg walk, where 24 00:01:20,080 --> 00:01:23,080 Speaker 1: you walk from side to side. That's a good one, 25 00:01:23,120 --> 00:01:25,759 Speaker 1: but that's not that that would just be bi Zoidberg 26 00:01:25,840 --> 00:01:28,160 Speaker 1: is a biped No no, no, no, I mean the 27 00:01:28,160 --> 00:01:30,560 Speaker 1: the Exorcist down the stairs. Well oh yes, yes, okay, 28 00:01:30,560 --> 00:01:34,200 Speaker 1: well that that would count, but I fully grant you 29 00:01:34,319 --> 00:01:36,679 Speaker 1: I probably wouldn't get around very quickly doing that all 30 00:01:36,680 --> 00:01:41,479 Speaker 1: the time. Other creatures, of course, are capable of bipedal locomotion, 31 00:01:41,560 --> 00:01:45,160 Speaker 1: but only employed under certain circumstances, like, for instance, a 32 00:01:45,240 --> 00:01:48,640 Speaker 1: lemur dancing you know, sort of prancing sideways across a 33 00:01:48,720 --> 00:01:53,440 Speaker 1: clearing between two trees, a giant ground sloth in in 34 00:01:53,680 --> 00:01:56,720 Speaker 1: in old and olden days, rising up to reach higher branches, 35 00:01:56,800 --> 00:01:59,120 Speaker 1: or or one of my favorites, a cat standing on 36 00:01:59,200 --> 00:02:02,160 Speaker 1: its hind lay eggs to better view pray or something 37 00:02:02,200 --> 00:02:05,320 Speaker 1: of interest. This is always a creepy, weird side if 38 00:02:05,320 --> 00:02:08,160 Speaker 1: you're lucky enough to witness it. Oh but it also 39 00:02:08,240 --> 00:02:11,440 Speaker 1: can be very cute when dogs stand on two legs 40 00:02:11,480 --> 00:02:13,480 Speaker 1: to to get up there closer to the treat that 41 00:02:13,520 --> 00:02:17,240 Speaker 1: they want. Oh, yeah, it's adorable. It's yeah. When dogs 42 00:02:17,280 --> 00:02:19,160 Speaker 1: do it, it's adorable. When cats do it, it is 43 00:02:19,400 --> 00:02:22,400 Speaker 1: it's a little unsettling, like they've suddenly become tiny people, 44 00:02:22,480 --> 00:02:25,840 Speaker 1: like they've been people all along, um or that's my 45 00:02:25,880 --> 00:02:28,800 Speaker 1: read on it. Now. When it comes to the hominans, 46 00:02:28,960 --> 00:02:33,200 Speaker 1: which again includes humans, the oldest evidence of bipedal movement 47 00:02:33,240 --> 00:02:36,680 Speaker 1: in a hominant species was probably six million years ago. 48 00:02:36,760 --> 00:02:39,760 Speaker 1: This would have been the selmthropists, and there's some dispute 49 00:02:39,800 --> 00:02:42,040 Speaker 1: over this, but any rate, we were mostly bipedal by 50 00:02:42,160 --> 00:02:45,239 Speaker 1: say four million years ago. We had a curved spine 51 00:02:45,280 --> 00:02:48,160 Speaker 1: by two point five million years ago, and it altered 52 00:02:48,160 --> 00:02:51,880 Speaker 1: our hip support by one point nine five million years ago, 53 00:02:52,600 --> 00:02:55,560 Speaker 1: and we were fully bipedal by the time of Fomo erectus, 54 00:02:55,680 --> 00:02:59,120 Speaker 1: with signature pelvis and thigh bones evident in the fossil record. 55 00:02:59,440 --> 00:03:03,160 Speaker 1: The legs lengthened over time, allowing for longer strides everything 56 00:03:03,200 --> 00:03:05,440 Speaker 1: that would enable the ministry of silly walks to do 57 00:03:05,520 --> 00:03:08,239 Speaker 1: its thing. Yeah. Now, some of what we know about 58 00:03:08,520 --> 00:03:11,799 Speaker 1: the posture and gate of our ancient ancestors and their 59 00:03:11,800 --> 00:03:15,080 Speaker 1: close relatives has to be inferred indirectly. I mean, you 60 00:03:15,080 --> 00:03:16,919 Speaker 1: can get a pretty good idea from like the shapes 61 00:03:16,960 --> 00:03:19,320 Speaker 1: of bones and stuff that that will tell you a lot. 62 00:03:19,840 --> 00:03:22,919 Speaker 1: There's other there's other evidence that's very direct. A great 63 00:03:22,960 --> 00:03:26,680 Speaker 1: piece of early direct evidence for bipedality is the fossil 64 00:03:26,720 --> 00:03:30,480 Speaker 1: formation known as the Late Totally Footprints. So, Robert, have 65 00:03:30,560 --> 00:03:32,720 Speaker 1: you have you seen what these look like? I think 66 00:03:32,800 --> 00:03:36,720 Speaker 1: I have everybody very cool in In nineteen seventy six 67 00:03:37,080 --> 00:03:40,200 Speaker 1: there was a team working with the paleontologist Mary Leaky, 68 00:03:40,240 --> 00:03:44,080 Speaker 1: and they discovered a collection of fossilized animal tracks in 69 00:03:44,200 --> 00:03:47,480 Speaker 1: late Totally Tanzania, which is south of the Old Duvai Gorge. 70 00:03:47,920 --> 00:03:50,720 Speaker 1: And the tracks were preserved in what had been a 71 00:03:50,800 --> 00:03:54,640 Speaker 1: soft bed of volcanic ash about three point six million 72 00:03:54,720 --> 00:03:57,440 Speaker 1: years ago or three point three point six three point 73 00:03:57,480 --> 00:04:01,120 Speaker 1: seven uh and it had hardened and been preserved for 74 00:04:01,200 --> 00:04:04,000 Speaker 1: us to discover in the twentieth century. And then so 75 00:04:04,120 --> 00:04:07,000 Speaker 1: after these tracks were initially discovered, in nineteen seventy eight, 76 00:04:07,000 --> 00:04:10,480 Speaker 1: Paul Able, a colleague of Leaky's, discovered that the formation 77 00:04:10,560 --> 00:04:14,000 Speaker 1: also contained a twenty seven meter or about eighty eight 78 00:04:14,000 --> 00:04:18,080 Speaker 1: foot long trail of ancient hominin footprints in addition to 79 00:04:18,160 --> 00:04:22,680 Speaker 1: the other animal footprints, probably made by Australian Epithecus afarensis, 80 00:04:22,839 --> 00:04:25,919 Speaker 1: the species to which Lucy belonged, And there were about 81 00:04:26,040 --> 00:04:29,640 Speaker 1: seventy hominin footprints at all in all in this formation. 82 00:04:30,160 --> 00:04:32,560 Speaker 1: And so the thing about these footprints is they're quite 83 00:04:32,640 --> 00:04:35,960 Speaker 1: clearly bipedal. You know, you're not seeing four legged movement, 84 00:04:36,000 --> 00:04:39,039 Speaker 1: and somebody was just walking on two feet through this 85 00:04:39,160 --> 00:04:43,000 Speaker 1: volcanic ash. The prints i've read are space close together, 86 00:04:43,080 --> 00:04:46,440 Speaker 1: meaning a short stride might mean short legs. And the 87 00:04:46,480 --> 00:04:49,359 Speaker 1: prints also show a big toe in line with the 88 00:04:49,400 --> 00:04:51,760 Speaker 1: foot rather than opposed to the foot, as you see 89 00:04:51,800 --> 00:04:54,920 Speaker 1: in arboreal apes. So like you know, your human big 90 00:04:54,960 --> 00:04:57,640 Speaker 1: toes go straight out, the arboreal apes have more kind 91 00:04:57,640 --> 00:05:00,600 Speaker 1: of a toe thumb, like a big toe thumb, uh, 92 00:05:00,600 --> 00:05:03,320 Speaker 1: that they used to climb trees and grab hold of stuff. 93 00:05:03,800 --> 00:05:06,880 Speaker 1: And also their footfalls apparently went heel toe, just like 94 00:05:06,920 --> 00:05:09,960 Speaker 1: ours tend to. So by about three point six million 95 00:05:10,000 --> 00:05:12,760 Speaker 1: years ago, we we've got direct evidence that our ancestors 96 00:05:12,760 --> 00:05:16,200 Speaker 1: and their close relatives were walking on two feet. Uh. 97 00:05:16,279 --> 00:05:19,080 Speaker 1: And I also can't help but mention I've read supposedly 98 00:05:19,120 --> 00:05:22,120 Speaker 1: there's this story of how the prints were discovered because 99 00:05:22,160 --> 00:05:26,120 Speaker 1: one of Leaky's colleagues, a paleo anthropologist named Andrew hill Uh, 100 00:05:26,240 --> 00:05:29,599 Speaker 1: stumbled across the fossil formation when he and another colleague 101 00:05:29,600 --> 00:05:34,159 Speaker 1: were running around throwing elephant poop at each other. Oh well, 102 00:05:34,560 --> 00:05:38,839 Speaker 1: you know you gotta keep it lighthearted on the dick, right, So, um, 103 00:05:39,040 --> 00:05:41,320 Speaker 1: like you said, we we know all of this based 104 00:05:41,400 --> 00:05:44,400 Speaker 1: on mostly fossil remains, and by that this, you know, 105 00:05:44,400 --> 00:05:46,760 Speaker 1: we're looking at the bones of our ancestors and observing 106 00:05:47,080 --> 00:05:50,520 Speaker 1: what the gradual shift to bipedalism did to us. And 107 00:05:50,560 --> 00:05:53,359 Speaker 1: it certainly certainly came at a cost. Yeah, now, to 108 00:05:53,400 --> 00:05:55,679 Speaker 1: be sure it was it was worth it, I guess. 109 00:05:55,680 --> 00:05:57,479 Speaker 1: I mean. It made it easier for us to pick 110 00:05:57,560 --> 00:06:00,440 Speaker 1: up fruits and pick up pick from a low line branches. 111 00:06:00,480 --> 00:06:04,040 Speaker 1: It gave us free hands for carrying food and also 112 00:06:04,160 --> 00:06:08,080 Speaker 1: very importantly carrying tools, carrying our young as well. It 113 00:06:08,160 --> 00:06:11,000 Speaker 1: allowed us to rise up and appear larger and more 114 00:06:11,120 --> 00:06:14,520 Speaker 1: fearsome to our enemies. Are many enemies of the wild. 115 00:06:14,600 --> 00:06:16,640 Speaker 1: This is something that I think we often don't think about. 116 00:06:16,760 --> 00:06:19,160 Speaker 1: But unless you're being instructed on how to react to 117 00:06:19,200 --> 00:06:22,040 Speaker 1: a bear in the win the wild, you know, they say, 118 00:06:22,080 --> 00:06:24,560 Speaker 1: make yourself as big as possible, and certainly there are 119 00:06:24,560 --> 00:06:28,600 Speaker 1: other animals that do just the same thing, but that's 120 00:06:28,640 --> 00:06:30,520 Speaker 1: one of the strengths of being able to at least 121 00:06:30,600 --> 00:06:32,960 Speaker 1: rise up on two feet. Yeah, now you can't know 122 00:06:33,040 --> 00:06:37,719 Speaker 1: this for sure, but I tend to think that bipedalism 123 00:06:37,920 --> 00:06:43,320 Speaker 1: is a sort of necessary precursor to advanced tool using intelligence. 124 00:06:43,360 --> 00:06:47,400 Speaker 1: I mean, you see some use of tools in quadrupedal apes, 125 00:06:48,040 --> 00:06:50,680 Speaker 1: but the fact that the fact that you're walking on 126 00:06:50,760 --> 00:06:54,760 Speaker 1: two feet gives you free hands, and having free hands, 127 00:06:54,880 --> 00:06:57,760 Speaker 1: it seems like suddenly you've got much more incentive to 128 00:06:57,839 --> 00:07:01,400 Speaker 1: be using them for all kinds of stuff. Well, it's 129 00:07:01,440 --> 00:07:03,679 Speaker 1: interesting when you think about the animals that do display 130 00:07:03,680 --> 00:07:05,440 Speaker 1: some form of tool use. I mean, certainly you have 131 00:07:05,520 --> 00:07:08,480 Speaker 1: the the apes, which are going to more or less 132 00:07:08,520 --> 00:07:10,320 Speaker 1: aligned with the human experience of tool use. But then 133 00:07:10,360 --> 00:07:12,880 Speaker 1: of course you have like the corvids uh and uh 134 00:07:12,920 --> 00:07:16,760 Speaker 1: and a few other birds that that also use tools. Now, 135 00:07:16,760 --> 00:07:21,600 Speaker 1: obviously they are engaging in bipedal ground movement. Their wings 136 00:07:21,600 --> 00:07:26,920 Speaker 1: are tucked away, but it's perhaps and it's a slightly 137 00:07:26,920 --> 00:07:30,320 Speaker 1: different situation with birds because those wings do have a purpose. Uh, 138 00:07:30,400 --> 00:07:33,960 Speaker 1: They've just specialized their their their beak functionality, and I've 139 00:07:34,040 --> 00:07:36,440 Speaker 1: learned how to use tools with that. The same is 140 00:07:36,440 --> 00:07:38,480 Speaker 1: truy of dolphins. You know they're using when they engage 141 00:07:38,480 --> 00:07:42,480 Speaker 1: in tool use, are using their snout um octopi slightly 142 00:07:42,480 --> 00:07:45,640 Speaker 1: different situation they have they have They have a wide 143 00:07:45,720 --> 00:07:49,760 Speaker 1: variety of limbs and are not necessarily gonna become bipedal 144 00:07:49,800 --> 00:07:52,320 Speaker 1: anytime soon. So anyway you shake it the back to 145 00:07:52,360 --> 00:07:55,080 Speaker 1: the human scenario, it helped us expand our range. It 146 00:07:55,240 --> 00:07:58,920 Speaker 1: It definitely played a part in our our ascension or dominance, 147 00:07:59,200 --> 00:08:02,400 Speaker 1: certainly our ability to invent things and expand, but we 148 00:08:02,480 --> 00:08:05,840 Speaker 1: also paid a price. We had to distribute all of 149 00:08:05,840 --> 00:08:08,360 Speaker 1: our weights on two limbs, resulting in all sorts of 150 00:08:08,360 --> 00:08:11,840 Speaker 1: painful experiences such as a lower back pain, slip discs, 151 00:08:12,200 --> 00:08:16,520 Speaker 1: arthritis in the lower body, fallen arches. Our spines are 152 00:08:16,640 --> 00:08:20,120 Speaker 1: ultimately just kind of weird. We evolved wider hips and 153 00:08:20,160 --> 00:08:22,040 Speaker 1: stronger knees to kind of cope with it to a 154 00:08:22,040 --> 00:08:25,800 Speaker 1: certain extent. But this is the reason that roughly of 155 00:08:25,840 --> 00:08:28,960 Speaker 1: adult humans will experience back pain in their lives. I 156 00:08:28,960 --> 00:08:31,760 Speaker 1: would say one of the biggest anatomical drawbacks is that 157 00:08:31,800 --> 00:08:34,400 Speaker 1: we can make finger guns at each other. I mean 158 00:08:34,440 --> 00:08:38,360 Speaker 1: that that is a true blow to the species you mean, 159 00:08:38,400 --> 00:08:41,240 Speaker 1: I mean the beneficial kind where like kids playing cowboys 160 00:08:41,240 --> 00:08:43,960 Speaker 1: and Indians or whatever on the playground, know the like 161 00:08:44,040 --> 00:08:48,640 Speaker 1: the like catch you later, bro Okay. So also it 162 00:08:48,679 --> 00:08:51,559 Speaker 1: also affected the way that we give birth and uh 163 00:08:51,600 --> 00:08:53,160 Speaker 1: and this is a I have to say, this is 164 00:08:53,160 --> 00:08:56,000 Speaker 1: a topic that we could easily have devoted an entire episode. 165 00:08:56,200 --> 00:09:00,720 Speaker 1: There's a lot of scholarship and debate on exactly how 166 00:09:00,760 --> 00:09:07,440 Speaker 1: the modern human birthing scenario pans out towards prehistoric examples, 167 00:09:07,480 --> 00:09:10,640 Speaker 1: but the move towards the bipedal form changed our skeletons. 168 00:09:10,679 --> 00:09:13,880 Speaker 1: This affected the pelvis. Most primates have a pretty straight 169 00:09:13,960 --> 00:09:17,640 Speaker 1: birth canal, but hominans soon boasted a narrow, distorted, kind 170 00:09:17,640 --> 00:09:20,760 Speaker 1: of fun house tube of a birth canal. The offspring 171 00:09:20,760 --> 00:09:22,800 Speaker 1: had to twist and turn in order to pass through. 172 00:09:23,200 --> 00:09:26,400 Speaker 1: This is true of our our ancestors. But our bodies 173 00:09:26,440 --> 00:09:29,760 Speaker 1: continued to evolve. We became taller, we grew larger brains. 174 00:09:29,880 --> 00:09:32,760 Speaker 1: That means meant bigger brained babies having to make it 175 00:09:32,840 --> 00:09:37,720 Speaker 1: through that twisting tunnel. Everything became tighter. Child birth became 176 00:09:37,760 --> 00:09:41,520 Speaker 1: a potentially more dangerous affair, because it also means giving 177 00:09:41,559 --> 00:09:44,120 Speaker 1: birth to a child an earlier stage of its development 178 00:09:44,120 --> 00:09:46,760 Speaker 1: in order to actually break it free from the confines 179 00:09:47,080 --> 00:09:50,520 Speaker 1: of our bipedally twisted bodies. Now, again, there's a lot 180 00:09:50,520 --> 00:09:52,680 Speaker 1: more to this. Scientists have gone back and forth on 181 00:09:52,720 --> 00:09:57,679 Speaker 1: the so called obstetric dilemma, but bipedal evolution certainly changed things. 182 00:09:58,320 --> 00:09:59,840 Speaker 1: All right, I think we should take a quick break. 183 00:10:00,000 --> 00:10:03,120 Speaker 1: We will be right back to discuss why bipedalism evolved 184 00:10:03,120 --> 00:10:08,959 Speaker 1: in humans. Thank alright, we're back. So this is a 185 00:10:09,000 --> 00:10:11,040 Speaker 1: big question because certainly we can point to all of 186 00:10:11,080 --> 00:10:14,240 Speaker 1: these like the pros and all the cons, but like, 187 00:10:14,280 --> 00:10:17,439 Speaker 1: what is the driving force right right now? What caused 188 00:10:17,640 --> 00:10:22,559 Speaker 1: our our ancient hominin ancestors to go on two legs? Primarily, 189 00:10:22,679 --> 00:10:25,240 Speaker 1: why did our ancestors become bipetle And this is an 190 00:10:25,240 --> 00:10:29,440 Speaker 1: ongoing debate. We know at some point we transitioned from 191 00:10:29,480 --> 00:10:32,680 Speaker 1: mostly four footed gate to a mostly two footed gate, 192 00:10:32,720 --> 00:10:34,920 Speaker 1: but why did it happen and what type of pressure 193 00:10:35,000 --> 00:10:38,760 Speaker 1: selected for this? So, first of all, when answering questions 194 00:10:38,800 --> 00:10:41,080 Speaker 1: like this, it's often hard to be certain, right, you know, 195 00:10:41,120 --> 00:10:44,800 Speaker 1: we only have the evidence we can find. Fossil evidence helps, 196 00:10:44,840 --> 00:10:47,880 Speaker 1: but it's hard to like run new experiments to test this. 197 00:10:48,000 --> 00:10:50,120 Speaker 1: We you know, we only have the fossil finds we 198 00:10:50,200 --> 00:10:53,240 Speaker 1: have and can only draw the conclusions we can draw 199 00:10:53,280 --> 00:10:56,320 Speaker 1: from them. And there have been all kinds of answers 200 00:10:56,320 --> 00:10:59,800 Speaker 1: over the years. So for a long time, consensus seem 201 00:10:59,840 --> 00:11:03,800 Speaker 1: to be that bipedalism was an adaptation to a change 202 00:11:03,840 --> 00:11:08,160 Speaker 1: in our primary habitat, as our ancestors moved down out 203 00:11:08,160 --> 00:11:12,199 Speaker 1: of the trees into a flat grassland, perhaps driven by 204 00:11:12,360 --> 00:11:16,320 Speaker 1: changing climate, like changing climate killed off forests and left 205 00:11:16,400 --> 00:11:19,199 Speaker 1: these you know, savannahs with tall grasses in their place, 206 00:11:20,200 --> 00:11:22,839 Speaker 1: or these creatures just moved down into the savannahs to 207 00:11:22,880 --> 00:11:26,160 Speaker 1: follow food sources or something. In this case, uh, these 208 00:11:26,160 --> 00:11:30,400 Speaker 1: hominins needed to stand up to see over the tall grass. 209 00:11:30,440 --> 00:11:33,560 Speaker 1: And this explanation is not still favored. This has fallen 210 00:11:33,600 --> 00:11:36,520 Speaker 1: out of favor among experts, and one reason is that 211 00:11:36,880 --> 00:11:41,079 Speaker 1: climate history analysis and physical fossil evidence indicate that we 212 00:11:41,080 --> 00:11:44,360 Speaker 1: were becoming bipedal at the same time that we were 213 00:11:44,400 --> 00:11:48,160 Speaker 1: still adapted to climbing and living in trees. And I 214 00:11:48,160 --> 00:11:50,439 Speaker 1: think there are multiple lines of evidence supporting this. It 215 00:11:50,720 --> 00:11:54,560 Speaker 1: appears that at some point our ancestors were both like 216 00:11:54,800 --> 00:11:58,200 Speaker 1: living in forests and climbing trees, but also having skeletons. 217 00:11:58,320 --> 00:12:02,920 Speaker 1: That's supported bipedal walking gate. Also, it's worth pointing out 218 00:12:03,000 --> 00:12:07,000 Speaker 1: that plenty of other animals that occupy areas with tall 219 00:12:07,040 --> 00:12:11,319 Speaker 1: grasses tall grasslands do just find staying on all fours right. 220 00:12:11,679 --> 00:12:13,920 Speaker 1: They don't need to stand up to see over the 221 00:12:13,960 --> 00:12:18,000 Speaker 1: grass in order to survive. Like grassland baboons today are 222 00:12:18,000 --> 00:12:20,920 Speaker 1: still quadrupedal. So that used to be what people thought, 223 00:12:21,000 --> 00:12:25,079 Speaker 1: but that is not no longer the main hypothesis. So 224 00:12:25,320 --> 00:12:28,160 Speaker 1: another theory that is popular with the public but not 225 00:12:28,320 --> 00:12:32,480 Speaker 1: with scientists in the relevant fields is the much much 226 00:12:32,520 --> 00:12:35,640 Speaker 1: beloved aquatic ape theory. Oh yes, we talked about this 227 00:12:35,800 --> 00:12:39,520 Speaker 1: um last year. Yeah, and our Aquatic Humanoids episode. We 228 00:12:39,600 --> 00:12:42,360 Speaker 1: concluded that there's not really any good evidence for this. 229 00:12:42,480 --> 00:12:46,520 Speaker 1: There's no direct fossil evidence for whatsoever. And the indirect 230 00:12:46,600 --> 00:12:49,440 Speaker 1: reasoning that causes people to think that there's evidence for 231 00:12:49,480 --> 00:12:52,559 Speaker 1: this is, uh, it's just not very good. But we 232 00:12:52,600 --> 00:12:54,679 Speaker 1: should mention it because this is bound to come up 233 00:12:54,679 --> 00:12:58,280 Speaker 1: whenever people address bipedality in its origins. I think it's 234 00:12:58,320 --> 00:13:01,160 Speaker 1: just because it's fun to imagine, maybe, and because it's 235 00:13:01,200 --> 00:13:04,960 Speaker 1: unconventional that makes it more interesting to people. Basically, it 236 00:13:05,040 --> 00:13:09,320 Speaker 1: says that the explanation for the main phenotypic variations between 237 00:13:09,440 --> 00:13:12,320 Speaker 1: us and our closest ape relatives is that our direct 238 00:13:12,360 --> 00:13:17,120 Speaker 1: ancestors briefly evolved to become water dwelling primates so sort 239 00:13:17,160 --> 00:13:21,320 Speaker 1: of like fishmen and uh, and then moved back to 240 00:13:21,440 --> 00:13:25,200 Speaker 1: dry land after that. And under this theory, bipedality evolves 241 00:13:25,320 --> 00:13:28,320 Speaker 1: because we need to keep our heads above water when 242 00:13:28,360 --> 00:13:32,000 Speaker 1: we're waiting around in search of shellfish for food. All Right, 243 00:13:32,280 --> 00:13:33,960 Speaker 1: it would be kind of like the idea that that 244 00:13:34,040 --> 00:13:36,640 Speaker 1: we became bipedal because we didn't want to get our 245 00:13:36,679 --> 00:13:41,680 Speaker 1: t shirts wet, you know, I mean, it's it's not 246 00:13:41,800 --> 00:13:44,760 Speaker 1: that bad, but yeah. So this was first proposed by 247 00:13:44,800 --> 00:13:48,040 Speaker 1: Alistair Hardy, and it was mainly developed by somebody named 248 00:13:48,040 --> 00:13:52,320 Speaker 1: Elaine Morgan. And in short, Morgan says, look, we're the 249 00:13:52,360 --> 00:13:55,760 Speaker 1: only mammal that consistently walks on two legs, but some 250 00:13:55,880 --> 00:13:58,920 Speaker 1: four legged animals can occasionally stand up on two legs 251 00:13:59,280 --> 00:14:02,679 Speaker 1: and wind. Do our closest stape relatives walk on two legs? Well? 252 00:14:02,720 --> 00:14:05,720 Speaker 1: She claims there's only one circumstance when they always walk 253 00:14:05,800 --> 00:14:08,080 Speaker 1: on two legs, and that's when they're waiting in water. 254 00:14:08,679 --> 00:14:12,400 Speaker 1: I see some pretty clear evidence running counter to this assertion, 255 00:14:12,760 --> 00:14:17,200 Speaker 1: just in publicly available video like primates. You look this up. 256 00:14:17,240 --> 00:14:20,280 Speaker 1: Primates sometimes stand up on two legs for all kinds 257 00:14:20,320 --> 00:14:23,480 Speaker 1: of reasons while carrying objects and moving around with them 258 00:14:23,680 --> 00:14:28,120 Speaker 1: during dominance displays to reach something like they don't. And 259 00:14:28,200 --> 00:14:30,800 Speaker 1: they also, on top of that, don't always stand up 260 00:14:30,840 --> 00:14:33,680 Speaker 1: when waiting in water. I found video of guerrillas waiting 261 00:14:33,680 --> 00:14:36,560 Speaker 1: around in water, and they tend to stay on all fours. 262 00:14:36,600 --> 00:14:39,320 Speaker 1: So if the classic explanation about seeing over the grass 263 00:14:39,400 --> 00:14:41,760 Speaker 1: is probably wrong and we don't put any stock in 264 00:14:41,800 --> 00:14:45,680 Speaker 1: the aquatic ape, what is the real explanation? Of course, 265 00:14:45,720 --> 00:14:47,040 Speaker 1: we still don't know, but there are a lot of 266 00:14:47,080 --> 00:14:51,200 Speaker 1: competing theories. Maybe there was a selection pressure on having 267 00:14:51,360 --> 00:14:55,080 Speaker 1: free hands, so maybe some of our ancestors began carrying 268 00:14:55,240 --> 00:14:59,840 Speaker 1: or throwing things, and for some reason this got started, 269 00:15:00,000 --> 00:15:03,119 Speaker 1: and then there was a great survival or reproduction advantage 270 00:15:03,160 --> 00:15:05,760 Speaker 1: for the ones that did this more and more of 271 00:15:05,800 --> 00:15:08,000 Speaker 1: the time. So being able this comes back to the 272 00:15:08,000 --> 00:15:10,120 Speaker 1: examples of being able to carry ones young, being able 273 00:15:10,160 --> 00:15:12,240 Speaker 1: to carry food that you've gathered, or being able to 274 00:15:12,280 --> 00:15:14,680 Speaker 1: carry a tool or a weapon, say a nice you 275 00:15:14,720 --> 00:15:18,200 Speaker 1: know jaw bone for smacking the other epe creatures around. Well, 276 00:15:18,360 --> 00:15:21,760 Speaker 1: I mean a big one I've seen suggested actually is throwing, 277 00:15:22,360 --> 00:15:26,800 Speaker 1: Like if if we evolved somehow a throwing hunting strategy 278 00:15:26,800 --> 00:15:29,800 Speaker 1: where you would throw objects, that this could have spurred 279 00:15:30,080 --> 00:15:33,640 Speaker 1: bipedality or some bridge to it. Another thing I was 280 00:15:33,680 --> 00:15:36,560 Speaker 1: reading about in a BBC article is that recent research 281 00:15:36,600 --> 00:15:41,560 Speaker 1: has suggested that perhaps partial bipedality helped these hominins adapt 282 00:15:41,600 --> 00:15:46,720 Speaker 1: to rocky, uneven terrain in geologically active areas. Essentially that 283 00:15:46,760 --> 00:15:50,200 Speaker 1: our ancestors were not only tree climbers, but rock climbers, 284 00:15:50,560 --> 00:15:52,920 Speaker 1: and this encouraged them to take on some traits that 285 00:15:53,000 --> 00:15:57,800 Speaker 1: bridge the gap to bipedalism. Another is, I guess sort 286 00:15:57,840 --> 00:16:01,240 Speaker 1: of the least the least interesting is an idea but 287 00:16:01,360 --> 00:16:03,400 Speaker 1: has seems to have a lot going for it, And 288 00:16:03,440 --> 00:16:06,800 Speaker 1: it's simply that a certain kind of bipedalism in tree 289 00:16:06,880 --> 00:16:11,400 Speaker 1: dwelling life became useful, as it is in many orangutans today. 290 00:16:11,440 --> 00:16:14,320 Speaker 1: Like you can look at orangutans living in the trees 291 00:16:15,120 --> 00:16:17,640 Speaker 1: that walk around on two feet, like they'll reach up 292 00:16:17,680 --> 00:16:20,680 Speaker 1: and grab branches with their arms over their heads while 293 00:16:20,720 --> 00:16:23,280 Speaker 1: walking around on other branches with two feet, it's just 294 00:16:23,320 --> 00:16:26,000 Speaker 1: a great way to anchor yourself between a lower and 295 00:16:26,280 --> 00:16:29,120 Speaker 1: upper branch. So there are a lot of competing theories. 296 00:16:29,200 --> 00:16:30,880 Speaker 1: I mean, I know there are other ones we didn't 297 00:16:30,920 --> 00:16:33,600 Speaker 1: even cover here, but this is this is an unsolved question. 298 00:16:33,640 --> 00:16:36,520 Speaker 1: We still don't know the answer now anyway to shake it. 299 00:16:36,840 --> 00:16:41,480 Speaker 1: We were not the first bipeds, not even close. I 300 00:16:41,480 --> 00:16:44,280 Speaker 1: already mentioned the t rex, you know that, that famous 301 00:16:44,320 --> 00:16:48,600 Speaker 1: the famous Cretaceous period, the carnivore Cretaceous spirit, of course, 302 00:16:48,640 --> 00:16:51,440 Speaker 1: banned hundred forty five million years ago to sixty six 303 00:16:51,440 --> 00:16:54,520 Speaker 1: million years ago. And this again, it's just an animal 304 00:16:54,560 --> 00:16:58,000 Speaker 1: that could scarcely be more of a biped you know, 305 00:16:58,160 --> 00:17:01,400 Speaker 1: those tiny little arms. And of course he or she 306 00:17:01,560 --> 00:17:04,040 Speaker 1: is just one of the many therapods that roamed the 307 00:17:04,040 --> 00:17:07,359 Speaker 1: prehistoric Earth, and in many cases not not not just 308 00:17:07,960 --> 00:17:11,880 Speaker 1: roamed it, but ran after their prey, running a key 309 00:17:11,920 --> 00:17:16,960 Speaker 1: advantage of their bipedal morphology. But even they, it seems 310 00:17:17,000 --> 00:17:19,919 Speaker 1: we're not the first. Um there's a two hundred and 311 00:17:20,040 --> 00:17:23,320 Speaker 1: ninety million year old fossil of a species that is 312 00:17:23,400 --> 00:17:28,480 Speaker 1: dubbed ood Obama's Kersaurus. This is a creature that was 313 00:17:28,800 --> 00:17:32,440 Speaker 1: very lizard like it seems, and it's a probable appearance, 314 00:17:32,760 --> 00:17:36,560 Speaker 1: had short fore limbs, relatively long tail and high and 315 00:17:36,880 --> 00:17:39,800 Speaker 1: also relatively long hind limbs. So these are kind of 316 00:17:39,800 --> 00:17:43,160 Speaker 1: the hallmarks of of a bipedal creature. But the other 317 00:17:43,200 --> 00:17:44,879 Speaker 1: curious thing about it is that it seems to have 318 00:17:44,920 --> 00:17:47,440 Speaker 1: been a herbivore rather than a meat eat or like 319 00:17:47,640 --> 00:17:51,840 Speaker 1: the theropods. Therefore it probably palin. I just think it 320 00:17:51,880 --> 00:17:56,520 Speaker 1: probably depended on bipedal running to flee from quadrupedal danger. 321 00:17:57,359 --> 00:18:01,920 Speaker 1: And on the subject of dinosaurs and quadrupedal and bipedal arrangement, 322 00:18:02,200 --> 00:18:06,000 Speaker 1: I found a two thousand five article in Astrobiology magazine 323 00:18:06,560 --> 00:18:10,919 Speaker 1: that brings up a species that is dubbed Masso spondulous. 324 00:18:11,240 --> 00:18:15,119 Speaker 1: And this is a pro sorrow pod now Sara pods 325 00:18:15,160 --> 00:18:19,040 Speaker 1: as everyone remember that. You know, they're the giant Diplodocus 326 00:18:19,520 --> 00:18:24,280 Speaker 1: Brachiosaurus style kind of creatures, you know, big, enormous quadrupeds. 327 00:18:24,280 --> 00:18:30,640 Speaker 1: It just enormous, just ponderous creatures. The pro sauropods, unlike 328 00:18:30,760 --> 00:18:34,600 Speaker 1: their descendants, they could rise up on their hind legs 329 00:18:34,680 --> 00:18:38,040 Speaker 1: and go after food bi petally. So back in two 330 00:18:38,080 --> 00:18:43,080 Speaker 1: thousand five, University of Toronto at Mississaugua thiss ut M 331 00:18:43,160 --> 00:18:46,719 Speaker 1: biology professor Robert Rice. He looked at an embryo of 332 00:18:46,760 --> 00:18:50,920 Speaker 1: one of these massospondulous creatures and he found the thing 333 00:18:51,040 --> 00:18:53,200 Speaker 1: was that it looked like a four legged saara pod. 334 00:18:53,800 --> 00:18:57,480 Speaker 1: So he hypothesized that it would have grown into a 335 00:18:57,560 --> 00:19:01,159 Speaker 1: full bipedal form as it matured. Uh this is what 336 00:19:01,200 --> 00:19:05,480 Speaker 1: he told Astro Astrobiology magazine quote. Because the embryo of 337 00:19:05,560 --> 00:19:09,719 Speaker 1: massospondos looks like a tiny saua pod with massive limbs 338 00:19:09,720 --> 00:19:12,520 Speaker 1: in a quadrupedal gait. We proposed in our paper that 339 00:19:12,560 --> 00:19:17,560 Speaker 1: the sauropods gate probably evolved through a phenomenon called ptomorphosis, 340 00:19:18,040 --> 00:19:21,560 Speaker 1: the retention of embryonic and juvenile features in the adult. 341 00:19:22,520 --> 00:19:25,000 Speaker 1: So this is interesting cause we're talking about a creature 342 00:19:25,080 --> 00:19:30,760 Speaker 1: that potentially adapted bipedal, the bipedal gate, but then left 343 00:19:30,800 --> 00:19:35,199 Speaker 1: it behind. Uh paedomor morphosis. By the way, it's it's 344 00:19:35,240 --> 00:19:38,479 Speaker 1: something we see today in various amphibian speeches species. But 345 00:19:38,560 --> 00:19:41,560 Speaker 1: for for these saua pods and for the true sauropods, 346 00:19:41,600 --> 00:19:44,480 Speaker 1: it would mean that they were essentially man babies of 347 00:19:44,520 --> 00:19:47,440 Speaker 1: the prehistoric world, like they simply no longer had to 348 00:19:47,480 --> 00:19:50,639 Speaker 1: grow up like they were the biggest forest eating dumpsters 349 00:19:50,680 --> 00:19:53,840 Speaker 1: on the planet, and therefore they really didn't have to 350 00:19:53,960 --> 00:19:57,560 Speaker 1: augment their more or less larval form anymore. You know, 351 00:19:57,680 --> 00:20:02,240 Speaker 1: I have often wondered something when looking at bipedal therapod 352 00:20:02,320 --> 00:20:06,200 Speaker 1: dinosaurs like the t rex. Just look at that powerful 353 00:20:06,280 --> 00:20:10,040 Speaker 1: lower body and then the tiny little baby arms out front. 354 00:20:10,840 --> 00:20:14,359 Speaker 1: If this dinosaur fell down or even just you know, 355 00:20:14,400 --> 00:20:16,320 Speaker 1: went to have a little lie down in the meadow, 356 00:20:16,880 --> 00:20:19,840 Speaker 1: how did it get back up. I'm not saying it 357 00:20:19,880 --> 00:20:23,760 Speaker 1: would be impossible, it just seems very awkward. Of course, 358 00:20:23,800 --> 00:20:25,960 Speaker 1: we're by peedle and we can get up from the ground, 359 00:20:25,960 --> 00:20:28,679 Speaker 1: but we have long arms and strong upper bodies to 360 00:20:28,720 --> 00:20:31,840 Speaker 1: help us. Try lying down on the ground and then 361 00:20:31,920 --> 00:20:34,600 Speaker 1: getting up without using your arms at all. You can 362 00:20:34,680 --> 00:20:37,240 Speaker 1: probably do it, but it's not so easy, is it? 363 00:20:37,960 --> 00:20:40,640 Speaker 1: And the t rex probably has an even lower relative 364 00:20:40,640 --> 00:20:43,960 Speaker 1: center of mass than you. So what's going on? Like, 365 00:20:44,480 --> 00:20:46,280 Speaker 1: was it this much of a struggle for the t 366 00:20:46,440 --> 00:20:48,800 Speaker 1: rex every time it had to get up from the ground. 367 00:20:49,040 --> 00:20:51,920 Speaker 1: That's a great question. Well, I've been wondering this for 368 00:20:51,960 --> 00:20:54,600 Speaker 1: a while. I finally looked it up. There's actually a 369 00:20:54,640 --> 00:20:57,720 Speaker 1: really good explainer on this in Scientific American provided by 370 00:20:57,760 --> 00:21:01,719 Speaker 1: the paleontologist Gregory M. Ericson of Florida State University. And 371 00:21:01,760 --> 00:21:04,000 Speaker 1: so here's what Erickson says. First of all, there has 372 00:21:04,320 --> 00:21:07,879 Speaker 1: long been a dispute over exactly what the t rex 373 00:21:07,960 --> 00:21:11,399 Speaker 1: is tiny four limbs were four uh maybe you know. 374 00:21:11,480 --> 00:21:13,880 Speaker 1: One idea says, maybe they're just a vestigial, meaning they're 375 00:21:13,880 --> 00:21:16,159 Speaker 1: actually not good for much of anything at all, and 376 00:21:16,200 --> 00:21:19,399 Speaker 1: they only existed in diminished form because the rex hadn't 377 00:21:19,440 --> 00:21:23,320 Speaker 1: fully lost them yet. And then the next idea says, well, 378 00:21:23,359 --> 00:21:27,679 Speaker 1: maybe they're grasping arms used in copulation. And then the 379 00:21:27,720 --> 00:21:30,119 Speaker 1: next idea says, maybe there's some sort of meat hook 380 00:21:30,320 --> 00:21:33,399 Speaker 1: for feeding chunks of flesh into the mouth. Though this 381 00:21:33,480 --> 00:21:36,080 Speaker 1: hypothesis was beaten down when it became clear that the 382 00:21:36,200 --> 00:21:38,800 Speaker 1: arms of a t rex could not reach its mouth. Yeah, 383 00:21:39,080 --> 00:21:40,640 Speaker 1: this is one of those things that when we went 384 00:21:40,640 --> 00:21:44,120 Speaker 1: to the museum in Chicago, the Field Museum, that became obvious. 385 00:21:44,359 --> 00:21:46,520 Speaker 1: You can when you go up to the arm, Uh, 386 00:21:46,960 --> 00:21:50,200 Speaker 1: the fossil bones of the t rex's arm, they are 387 00:21:50,200 --> 00:21:53,119 Speaker 1: the size of my arm. But the t rex is 388 00:21:53,160 --> 00:21:55,840 Speaker 1: the size of like a two story house. And uh, 389 00:21:56,760 --> 00:22:01,440 Speaker 1: clearly this is a shrunken limb exactly. But another hypothesis 390 00:22:01,960 --> 00:22:06,360 Speaker 1: is that the baby arms were useful exactly for helping 391 00:22:06,400 --> 00:22:08,400 Speaker 1: the t rex get back up when it was lying 392 00:22:08,440 --> 00:22:10,840 Speaker 1: on the ground. So in the year nine seventy, the 393 00:22:10,880 --> 00:22:15,400 Speaker 1: British paleontologist Barney Newman speculated that maybe the arms could 394 00:22:15,400 --> 00:22:17,240 Speaker 1: help the t rex do a do a thing kind 395 00:22:17,240 --> 00:22:19,160 Speaker 1: of like a push up. It would be a push 396 00:22:19,240 --> 00:22:21,800 Speaker 1: up motion where the where it would help the rex 397 00:22:21,880 --> 00:22:25,240 Speaker 1: keep from sliding forward along the ground as it tried 398 00:22:25,280 --> 00:22:28,760 Speaker 1: to raise its body to a standing position. Just imagine 399 00:22:28,760 --> 00:22:31,560 Speaker 1: trying to rise without anything to brace you, like lie 400 00:22:31,560 --> 00:22:34,720 Speaker 1: flat on your stomach and then try to push yourself 401 00:22:34,800 --> 00:22:38,240 Speaker 1: up to standing using your legs alone. You might be 402 00:22:38,280 --> 00:22:40,320 Speaker 1: able to do it, but it's not easy. It's a 403 00:22:40,320 --> 00:22:42,280 Speaker 1: lot easier if you can use your arms right, and 404 00:22:42,280 --> 00:22:44,480 Speaker 1: it requires a fair amount of sort of coiling and 405 00:22:44,480 --> 00:22:47,320 Speaker 1: slithering around for for most people, I think, And it's 406 00:22:47,359 --> 00:22:49,320 Speaker 1: it's easier to imagine that kind of movement in our 407 00:22:49,359 --> 00:22:53,240 Speaker 1: bodies as opposed to the t rex. Yes, so Ericson says, 408 00:22:53,359 --> 00:22:55,560 Speaker 1: you know, now we know more about the biomechanics of 409 00:22:55,600 --> 00:22:57,639 Speaker 1: the t rex than we did back when these ideas 410 00:22:57,640 --> 00:23:00,919 Speaker 1: were hypothesized. So of course, and I'm one. As we mentioned, 411 00:23:00,920 --> 00:23:03,000 Speaker 1: the arms can't reach them out the mouth, so the 412 00:23:03,040 --> 00:23:06,240 Speaker 1: meat hook theory that's dead. One thing we have learned 413 00:23:06,320 --> 00:23:10,000 Speaker 1: is that t rex arms were often broken during life, 414 00:23:10,160 --> 00:23:13,119 Speaker 1: as opposed to in an injury that immediately caused death. 415 00:23:13,720 --> 00:23:16,040 Speaker 1: And this tells us some interesting things. First of all, 416 00:23:16,040 --> 00:23:18,560 Speaker 1: it tells us that the arms were probably kind of 417 00:23:18,600 --> 00:23:21,879 Speaker 1: bad at whatever the rexes were using them for. And 418 00:23:22,000 --> 00:23:26,040 Speaker 1: number two, they were not absolutely necessary for survival. The 419 00:23:26,080 --> 00:23:29,359 Speaker 1: fact that we could have like examples of them having 420 00:23:29,600 --> 00:23:33,200 Speaker 1: healed or not immediately killed the rex means that the 421 00:23:33,280 --> 00:23:35,960 Speaker 1: rex could break an arm and survive for at least 422 00:23:35,960 --> 00:23:38,879 Speaker 1: a month afterward. If an animal in the wild breaks 423 00:23:38,880 --> 00:23:41,800 Speaker 1: a survival essential limb, that I mean that animal is 424 00:23:41,800 --> 00:23:44,840 Speaker 1: generally pretty much done for, right, like a cheetah breaking 425 00:23:44,840 --> 00:23:47,800 Speaker 1: a leg, etcetera. It's it's, it's done. And this suggests 426 00:23:47,800 --> 00:23:51,560 Speaker 1: four limbs that were not survival essential. Also, though the 427 00:23:51,640 --> 00:23:54,159 Speaker 1: rex arms would have been strong by our standards, like 428 00:23:54,200 --> 00:23:57,199 Speaker 1: he says they could probably curl four hundred pounds, they 429 00:23:57,200 --> 00:24:00,040 Speaker 1: would not have had strong enough bone structure in the 430 00:24:00,080 --> 00:24:03,840 Speaker 1: wrists to lift what he calls large mechanical loads, and 431 00:24:03,880 --> 00:24:06,760 Speaker 1: that would include the rex's own body. So this means 432 00:24:06,840 --> 00:24:10,679 Speaker 1: Newman's push up hypothesis is probably wrong, right, that the 433 00:24:10,760 --> 00:24:12,400 Speaker 1: t rex did a push up in order to get 434 00:24:12,440 --> 00:24:14,920 Speaker 1: up from the ground. So how did they get up 435 00:24:14,960 --> 00:24:17,879 Speaker 1: once they were lying down? Well Ericson suggests looking to 436 00:24:18,000 --> 00:24:20,760 Speaker 1: birds who get up without the aid of four limbs, 437 00:24:20,800 --> 00:24:23,200 Speaker 1: and apparently what they do is they simply tuck their 438 00:24:23,280 --> 00:24:26,800 Speaker 1: legs directly underneath their center of gravity and then push 439 00:24:26,880 --> 00:24:30,200 Speaker 1: straight up. Actually, probably sort of the exact same thing 440 00:24:30,240 --> 00:24:31,919 Speaker 1: you would do if you tried to stand up from 441 00:24:31,960 --> 00:24:35,119 Speaker 1: the ground without using your arms. You try to gather 442 00:24:35,280 --> 00:24:39,080 Speaker 1: your legs under you and then push up right. Yeah, exactly. 443 00:24:39,359 --> 00:24:42,480 Speaker 1: But also therapod dinosaurs with tiny arms like the t 444 00:24:42,640 --> 00:24:45,320 Speaker 1: rex would have had the aid of their tails to 445 00:24:45,440 --> 00:24:48,919 Speaker 1: help gain additional leverage or bracing against the ground. So 446 00:24:49,000 --> 00:24:51,359 Speaker 1: the way I'm imagining this I could be wrong, but 447 00:24:51,520 --> 00:24:54,439 Speaker 1: it's the same way you would brace your hands against 448 00:24:54,480 --> 00:24:57,480 Speaker 1: the ground in front of you while extending your legs 449 00:24:57,520 --> 00:25:00,760 Speaker 1: to stand up. Imagine a t rex may being able 450 00:25:00,800 --> 00:25:04,320 Speaker 1: to brace its tail against the ground behind it while 451 00:25:04,359 --> 00:25:07,320 Speaker 1: pushing up with its legs, a sort of backwards standing. 452 00:25:08,240 --> 00:25:10,120 Speaker 1: You know, all of this, I think it goes It's 453 00:25:10,119 --> 00:25:12,720 Speaker 1: just another reminder that the t Rex one of the 454 00:25:12,760 --> 00:25:16,680 Speaker 1: most famous dinosaurs, if not the most famous dinosaur, that 455 00:25:16,800 --> 00:25:19,960 Speaker 1: was the specimen out there, and also one that we 456 00:25:19,960 --> 00:25:22,480 Speaker 1: we know a fair amount about there in a number 457 00:25:22,600 --> 00:25:25,600 Speaker 1: of the fossils that have been found, and yet there 458 00:25:25,640 --> 00:25:27,879 Speaker 1: are there's there's so much that we do not know 459 00:25:27,960 --> 00:25:30,439 Speaker 1: about the t Rex. There are things about it that 460 00:25:30,520 --> 00:25:32,560 Speaker 1: we will we will never know unless we get that 461 00:25:33,080 --> 00:25:36,000 Speaker 1: time machine to go back and start hunting them, or 462 00:25:36,000 --> 00:25:38,399 Speaker 1: if we somehow bring them back to life with a 463 00:25:38,520 --> 00:25:41,399 Speaker 1: Jurassic Park scenario. I propose a pre emptive ban on 464 00:25:41,480 --> 00:25:44,480 Speaker 1: dinosaur hunting before we have any time machines. We've got 465 00:25:44,480 --> 00:25:46,880 Speaker 1: to get the regulations in place. That's right, We've got 466 00:25:46,880 --> 00:25:49,560 Speaker 1: to think ahead of our technology. Alright. Well, on that note, 467 00:25:49,600 --> 00:25:51,240 Speaker 1: we're going to take a quick break and we'll be 468 00:25:51,359 --> 00:25:56,399 Speaker 1: right back. Thank alright, we're back, alright. So one of 469 00:25:56,440 --> 00:25:58,960 Speaker 1: the big questions I had to in all of this is, alright, 470 00:25:59,000 --> 00:26:03,120 Speaker 1: we we've looked at bipeds in prehistoric times, look at 471 00:26:03,160 --> 00:26:06,560 Speaker 1: the bipedal world around us, uh that the humans have built. 472 00:26:07,160 --> 00:26:09,080 Speaker 1: We're always trying to figure out what's going on or 473 00:26:09,119 --> 00:26:11,400 Speaker 1: what could be going on in other worlds, What other 474 00:26:11,480 --> 00:26:16,200 Speaker 1: kinds of life have evolved, are evolving, or will evolve 475 00:26:16,240 --> 00:26:19,880 Speaker 1: in the future. So, assuming the entire universe isn't dead 476 00:26:20,520 --> 00:26:24,400 Speaker 1: other than us, which you know, might be right. So, um, 477 00:26:24,680 --> 00:26:28,320 Speaker 1: what's the deal? Would we find legged creatures on other worlds? 478 00:26:28,440 --> 00:26:32,320 Speaker 1: And if we did, would we find bipedal creatures? We 479 00:26:32,359 --> 00:26:37,400 Speaker 1: can certainly imagine extraterrestrial life that doesn't depend on legged locomotion, 480 00:26:37,720 --> 00:26:42,159 Speaker 1: but intelligent life, life capable of achieving technology along the 481 00:26:42,200 --> 00:26:44,840 Speaker 1: same lines as the human model. You know, we've we've 482 00:26:44,880 --> 00:26:46,600 Speaker 1: got into this a bit in the past, discussing the 483 00:26:46,600 --> 00:26:49,680 Speaker 1: notion of say a hypothetical aquatic species and what sort 484 00:26:49,680 --> 00:26:53,000 Speaker 1: of technology they might be able to develop. Uh. As 485 00:26:53,040 --> 00:26:57,080 Speaker 1: technico technology entails the mina manipulation of matter, one would 486 00:26:57,080 --> 00:27:01,679 Speaker 1: need some sort of limbs of manipulation. Now, terrestrial nature 487 00:27:01,760 --> 00:27:05,639 Speaker 1: provides us with other forms of manipulation beyond UH. You know, 488 00:27:05,680 --> 00:27:07,639 Speaker 1: our hands, in our arms, they are the arms and 489 00:27:07,640 --> 00:27:12,080 Speaker 1: tentacles of cephalopods. Uh, one could maybe turned to pseudopods 490 00:27:12,119 --> 00:27:14,719 Speaker 1: and UH and other organisms so they're not used for 491 00:27:14,720 --> 00:27:17,000 Speaker 1: tool use. But if we're just imagining some sort of 492 00:27:17,000 --> 00:27:20,960 Speaker 1: an organism manipulating things, I think pseudopods are on the table. 493 00:27:21,440 --> 00:27:24,920 Speaker 1: I just had a crazy idea, what about a magnetic organism, 494 00:27:24,960 --> 00:27:27,760 Speaker 1: like it's got like a skin surface that can manipulate 495 00:27:27,840 --> 00:27:32,199 Speaker 1: things by changing magnetic attraction or yeah, or it's picked up. 496 00:27:32,200 --> 00:27:34,680 Speaker 1: I mean there are animals in the natural world that 497 00:27:34,920 --> 00:27:38,240 Speaker 1: utilize magnetism to a certain extent, right, so maybe there's 498 00:27:38,240 --> 00:27:40,720 Speaker 1: something there. Um. But when we try and think of 499 00:27:40,720 --> 00:27:45,120 Speaker 1: tool users that engage in tool use, uh without engaging 500 00:27:45,119 --> 00:27:48,400 Speaker 1: in pipedal movement, well, you know, a few varieties of 501 00:27:48,400 --> 00:27:51,440 Speaker 1: of octopus come to mind. Uh. We can think of dolphins, 502 00:27:52,119 --> 00:27:54,000 Speaker 1: and we of course do see a lot of bipedole 503 00:27:54,160 --> 00:27:57,560 Speaker 1: use in apes and birds. But then we have these 504 00:27:57,600 --> 00:28:00,760 Speaker 1: animals that engage in tool use via the mouthparts or 505 00:28:00,760 --> 00:28:03,679 Speaker 1: in the case of elephants, with their trunks. You know 506 00:28:03,760 --> 00:28:06,880 Speaker 1: Ian M. Banks, the sci Fia writer, he actually explored 507 00:28:06,920 --> 00:28:11,000 Speaker 1: this idea, uh in his excellent novel Surface Detail. There 508 00:28:11,000 --> 00:28:15,120 Speaker 1: are these creatures called the the pav Pavoolians, and they 509 00:28:15,119 --> 00:28:18,240 Speaker 1: are they're like an elephant like quadrupedal species, but they 510 00:28:18,240 --> 00:28:21,800 Speaker 1: have a pair of trunks that they use for tool use. 511 00:28:21,840 --> 00:28:26,320 Speaker 1: In computer interface in the front, now, I was looking 512 00:28:26,359 --> 00:28:29,000 Speaker 1: around for for any writings on this subject, and I 513 00:28:29,080 --> 00:28:33,439 Speaker 1: ran across UH this paper Some engineering considerations on the 514 00:28:33,480 --> 00:28:38,040 Speaker 1: controversial issue of humanoids by Gean Carlo Guinta from the 515 00:28:38,040 --> 00:28:41,720 Speaker 1: Department of Mechanics and UH. This is UH from the 516 00:28:41,800 --> 00:28:46,160 Speaker 1: Polytechnico Deterreno and this was collected in Cellular Origin, Life 517 00:28:46,160 --> 00:28:52,240 Speaker 1: and Extreme Habitats and Astrobiology and UH. Guinta actually lays 518 00:28:52,240 --> 00:28:56,400 Speaker 1: out much of what I said concerning UH possible mobility methods, 519 00:28:56,760 --> 00:29:00,360 Speaker 1: UH and more in a very succinct way. He writes, quote, 520 00:29:00,360 --> 00:29:03,440 Speaker 1: mobility of a living being is strictly linked with how 521 00:29:03,480 --> 00:29:06,920 Speaker 1: it gets its food and energy. Autotrophic beings may not 522 00:29:07,160 --> 00:29:12,320 Speaker 1: need any sort of mobility, while heterotrophic ones and particularly predators, 523 00:29:12,840 --> 00:29:16,680 Speaker 1: usually need to move to obtain food. Large animals either 524 00:29:16,720 --> 00:29:19,440 Speaker 1: are supported on a solid surface, float in a fluid 525 00:29:19,520 --> 00:29:24,600 Speaker 1: under the effect of hydrostatic forces, or fly using aerodynamic forces. 526 00:29:25,080 --> 00:29:28,760 Speaker 1: Very small beings may use other supporting mechanisms like surface tension, 527 00:29:29,040 --> 00:29:32,720 Speaker 1: molecular interactions, etcetera. Since it is likely that an intelligent 528 00:29:32,800 --> 00:29:36,640 Speaker 1: being has a minimum size larger than allowing to to 529 00:29:36,720 --> 00:29:39,720 Speaker 1: use these mechanisms, they will not be considered. Other solutions 530 00:29:39,720 --> 00:29:43,360 Speaker 1: like magnetic levitation or jets are conceivable, but are quite 531 00:29:43,440 --> 00:29:46,960 Speaker 1: hypothetical and will not be considered and uh. He goes 532 00:29:47,000 --> 00:29:49,960 Speaker 1: on to point out that most animals on solid surface 533 00:29:50,160 --> 00:29:52,760 Speaker 1: surfaces do have legs, and the evolution on our planet 534 00:29:52,760 --> 00:29:55,240 Speaker 1: at least is characterized by a gradual reduction in the 535 00:29:55,320 --> 00:30:00,000 Speaker 1: number of legs. He continues quote in general, the large 536 00:30:00,200 --> 00:30:02,440 Speaker 1: is the animal and the lower is the gravity of 537 00:30:02,440 --> 00:30:05,600 Speaker 1: the planet. The easier it is to remain an equilibrium 538 00:30:05,680 --> 00:30:08,360 Speaker 1: on a small number of legs, in the sense that 539 00:30:08,440 --> 00:30:11,320 Speaker 1: the response of the nervous system to avoid falling down 540 00:30:11,400 --> 00:30:14,720 Speaker 1: maybe less quick. From this point of view, low gravity, 541 00:30:15,080 --> 00:30:18,920 Speaker 1: uh simplifies all operations related to motion. They go on 542 00:30:18,960 --> 00:30:21,080 Speaker 1: to point out that the speed is important, that speed 543 00:30:21,080 --> 00:30:23,480 Speaker 1: of course, is important for survival and uh and it's 544 00:30:23,520 --> 00:30:26,800 Speaker 1: an important factor in natural selection. And we can see 545 00:30:26,840 --> 00:30:31,200 Speaker 1: this reflected in our dinosaur examples, right, are prehistoric creature examples, 546 00:30:31,240 --> 00:30:34,160 Speaker 1: because something like the t rex is running quickly to 547 00:30:34,240 --> 00:30:37,960 Speaker 1: catch prey, as are its theropod um um uh kin. 548 00:30:38,440 --> 00:30:41,680 Speaker 1: And then that earlier example, the kind of weird lizard 549 00:30:41,720 --> 00:30:45,320 Speaker 1: herbivore that would have conceivably been running to escape from predator. 550 00:30:45,360 --> 00:30:48,480 Speaker 1: It seems another example where so much in evolution ends 551 00:30:48,560 --> 00:30:51,200 Speaker 1: up having to do with speed. Like you know, when 552 00:30:51,240 --> 00:30:54,720 Speaker 1: we talked about what called the ideas behind what caused 553 00:30:54,720 --> 00:30:57,800 Speaker 1: the Cambrian explosion, you know, this is another big open 554 00:30:57,920 --> 00:31:01,320 Speaker 1: question in UH, in paleon oology and in the history 555 00:31:01,320 --> 00:31:04,880 Speaker 1: of biology and evolution UH. And one of the ideas 556 00:31:04,920 --> 00:31:10,520 Speaker 1: there is that maybe suddenly the introduction of predation into 557 00:31:10,520 --> 00:31:15,120 Speaker 1: the food chain drove an explosion in body plan adaptation 558 00:31:15,160 --> 00:31:18,760 Speaker 1: because suddenly things needed to protect themselves and move quickly 559 00:31:18,880 --> 00:31:22,000 Speaker 1: in order to survive or in order to well sylvia, 560 00:31:22,040 --> 00:31:26,240 Speaker 1: in order to survive, to catch or evade predation. Indeed, 561 00:31:26,520 --> 00:31:28,800 Speaker 1: so again to continues and says that all of this 562 00:31:29,320 --> 00:31:32,960 Speaker 1: UH means there will be quote a strong incentive to 563 00:31:33,040 --> 00:31:37,400 Speaker 1: shift from walking a sequel of static equilibrium positions to running, 564 00:31:37,480 --> 00:31:40,760 Speaker 1: which includes positions in which static equilibrium is not guaranteed. 565 00:31:41,320 --> 00:31:45,000 Speaker 1: Large animals, possibly with a smaller number of legs may 566 00:31:45,000 --> 00:31:47,800 Speaker 1: have been an advantage, and bipeds are a very good 567 00:31:47,800 --> 00:31:52,520 Speaker 1: configuration for beings having an adequate controlled system. This is interesting. 568 00:31:52,520 --> 00:31:54,920 Speaker 1: So he's pointing out how one of the features of 569 00:31:55,040 --> 00:31:58,040 Speaker 1: running is that that, like you, you can be off 570 00:31:58,120 --> 00:32:00,520 Speaker 1: balance while you're running, because it's the same way like 571 00:32:00,520 --> 00:32:03,560 Speaker 1: a bicycle works. You know, a bicycle works because you're 572 00:32:03,560 --> 00:32:06,120 Speaker 1: by maintaining speed, you could do this thing that you 573 00:32:06,120 --> 00:32:08,760 Speaker 1: couldn't stay balanced to the lower speed. Yeah. And if 574 00:32:08,760 --> 00:32:12,480 Speaker 1: you're the t rex, ideally that that that herbivore is 575 00:32:12,480 --> 00:32:14,959 Speaker 1: going to break your fall and you're gonna do it 576 00:32:15,120 --> 00:32:20,080 Speaker 1: with mouth wide open. Right. So they also touch on 577 00:32:20,080 --> 00:32:22,920 Speaker 1: the fact that that tool use and manipulation amounts to 578 00:32:22,960 --> 00:32:26,280 Speaker 1: a shortcut and evolution uh quote objects that increase the 579 00:32:26,280 --> 00:32:31,000 Speaker 1: potentialities of its body working like prostheses. Uh Why why 580 00:32:31,120 --> 00:32:33,440 Speaker 1: slowly augment your body over the course of you know, 581 00:32:33,560 --> 00:32:35,840 Speaker 1: long stretches of time when you can do something like 582 00:32:35,880 --> 00:32:38,840 Speaker 1: this within a lifetime be a tool use. So they 583 00:32:38,840 --> 00:32:41,760 Speaker 1: conclude that such an alien, if if we're trying to 584 00:32:41,960 --> 00:32:44,760 Speaker 1: imagine an alien emerging in another world, that it would 585 00:32:44,760 --> 00:32:48,280 Speaker 1: need to have some sort of of locomotion and some 586 00:32:48,320 --> 00:32:52,880 Speaker 1: sort of manipulation organs quote the ladder being best derived 587 00:32:53,000 --> 00:32:57,000 Speaker 1: from locomotion organs like legs, the humanoid layout with two 588 00:32:57,080 --> 00:33:01,120 Speaker 1: arms and two legs seems to be optimal. This is 589 00:33:01,160 --> 00:33:05,400 Speaker 1: an interesting point. Yeah, I would I would have maybe said, okay, uh, 590 00:33:05,440 --> 00:33:08,760 Speaker 1: who knows how many legs an alien we encounter might have, 591 00:33:08,880 --> 00:33:12,160 Speaker 1: but if it's moving around on the land, I think 592 00:33:12,360 --> 00:33:14,480 Speaker 1: this is some pretty solid reasoning. There tends to be 593 00:33:14,560 --> 00:33:17,920 Speaker 1: evolution toward fewer numbers of legs over time for to 594 00:33:18,000 --> 00:33:22,600 Speaker 1: increase speed, and that this can free up other limbs 595 00:33:22,600 --> 00:33:25,440 Speaker 1: for tool use, which seems to be an important part 596 00:33:25,640 --> 00:33:29,160 Speaker 1: of tool using intelligence. Like you, you wouldn't need tool 597 00:33:29,240 --> 00:33:33,640 Speaker 1: using intelligence if you didn't have hands to use tools with, right, Yeah, 598 00:33:33,760 --> 00:33:36,440 Speaker 1: it's it's it's an interesting paper. I'm sure there's some 599 00:33:36,560 --> 00:33:41,360 Speaker 1: there's some astrobiologists and biologists that might evolutionary biologist that 600 00:33:41,400 --> 00:33:44,200 Speaker 1: may take issue with this, but but I think I 601 00:33:44,200 --> 00:33:47,920 Speaker 1: think the author makes an interesting argument here. And it 602 00:33:48,000 --> 00:33:50,920 Speaker 1: also as much as I love multi legged aliens in 603 00:33:50,960 --> 00:33:53,760 Speaker 1: my sci fi, it also gives me a little support 604 00:33:53,840 --> 00:33:58,960 Speaker 1: for visions of bipedal aliens being the dominant UH form 605 00:33:59,080 --> 00:34:02,120 Speaker 1: in so many different science fiction visions. Now, this also 606 00:34:02,200 --> 00:34:06,360 Speaker 1: makes me question what unexamined assumptions are we bringing on 607 00:34:06,440 --> 00:34:09,560 Speaker 1: void that could be clouding our vision Right here, we're 608 00:34:10,000 --> 00:34:13,399 Speaker 1: we're thinking, Okay, I'm just trying to universalize about like 609 00:34:13,480 --> 00:34:17,400 Speaker 1: the physics of planets and the principles of evolution and 610 00:34:17,480 --> 00:34:21,399 Speaker 1: not be you know, Earth chauvinist. But but I bet 611 00:34:21,440 --> 00:34:24,560 Speaker 1: there are ways that that we're somehow being Earth chauvinists 612 00:34:24,560 --> 00:34:28,160 Speaker 1: that we're not noticing. Yeah, and I we haven't even 613 00:34:28,200 --> 00:34:30,799 Speaker 1: talked about tales. I can easily imagine some sort of 614 00:34:30,920 --> 00:34:34,400 Speaker 1: an alien creature with a prehensile tail um or you know, 615 00:34:34,480 --> 00:34:37,520 Speaker 1: some other prehensile uh that if they're an animate that 616 00:34:37,560 --> 00:34:40,279 Speaker 1: they're able to use for tool use and manipulation. Well, 617 00:34:40,320 --> 00:34:41,920 Speaker 1: to bring it back to the t rex is, I 618 00:34:41,960 --> 00:34:43,759 Speaker 1: think we did mention this, but despite the fact that 619 00:34:43,840 --> 00:34:47,080 Speaker 1: we don't have tales, tales often form an extremely important 620 00:34:47,120 --> 00:34:50,680 Speaker 1: part of bipedal locomotion. The tails are there to counter 621 00:34:50,800 --> 00:34:52,960 Speaker 1: as a counterweight for the front of the body. If 622 00:34:53,000 --> 00:34:55,120 Speaker 1: you've only got two legs and you're like a t rex, 623 00:34:55,160 --> 00:34:57,520 Speaker 1: you're leading forward. You know, you saw these old pictures 624 00:34:57,520 --> 00:34:59,759 Speaker 1: where people used to illustrate t rex is with their 625 00:34:59,760 --> 00:35:02,279 Speaker 1: tail is dragging on the ground. That doesn't make any 626 00:35:02,280 --> 00:35:04,400 Speaker 1: sense that they of course had to have their tails 627 00:35:04,480 --> 00:35:06,400 Speaker 1: up in the air as a counterweight to the body 628 00:35:06,440 --> 00:35:10,040 Speaker 1: so they could move. Yeah. I am also reminded of kangaroos, 629 00:35:10,080 --> 00:35:15,040 Speaker 1: who have you know, engage in bipedal gates and their 630 00:35:15,080 --> 00:35:18,160 Speaker 1: tails is often utilized as a is a third limb. 631 00:35:19,120 --> 00:35:20,879 Speaker 1: So yeah, there's a whole bunch that we could do there. 632 00:35:20,880 --> 00:35:24,160 Speaker 1: I also have to say there's a whole episode we 633 00:35:24,320 --> 00:35:28,320 Speaker 1: should probably record on just bipedal robots and the attempt 634 00:35:28,400 --> 00:35:31,600 Speaker 1: to create functional bipedal robots, and perhaps getting into the 635 00:35:31,640 --> 00:35:34,160 Speaker 1: idea of why we want to do it as well, 636 00:35:34,360 --> 00:35:36,440 Speaker 1: because they've got to be like us, gotta be like us. 637 00:35:36,560 --> 00:35:40,239 Speaker 1: We got to create a mechanical man. So we'll will 638 00:35:40,480 --> 00:35:43,279 Speaker 1: inevitably come back to that topic in a future episode, 639 00:35:43,320 --> 00:35:47,080 Speaker 1: but for now, there you have it. Bipedalism something we do, 640 00:35:47,360 --> 00:35:50,200 Speaker 1: something other organisms do, something organisms have been doing on 641 00:35:50,200 --> 00:35:53,719 Speaker 1: this planet for a very long time, and conceivably there 642 00:35:53,760 --> 00:35:56,600 Speaker 1: could be other bipeds out there in the universe doing 643 00:35:56,640 --> 00:35:59,120 Speaker 1: their thing as well. Now, if you want to check 644 00:35:59,120 --> 00:36:01,120 Speaker 1: out more episodes of Have to Blow Your Mind, head 645 00:36:01,120 --> 00:36:02,839 Speaker 1: on over to stuff to Blow your Mind dot com. 646 00:36:02,880 --> 00:36:05,480 Speaker 1: That's where we'll find all the podcast episodes, links out 647 00:36:05,480 --> 00:36:09,120 Speaker 1: to our social media accounts. A store tab for our 648 00:36:09,200 --> 00:36:11,680 Speaker 1: t public story. You can find all sorts of cool designs, 649 00:36:11,840 --> 00:36:14,840 Speaker 1: including the new uh squirrel shirt that we have. This 650 00:36:15,000 --> 00:36:17,439 Speaker 1: is the squirrels are not what they've seen because they're 651 00:36:17,480 --> 00:36:19,880 Speaker 1: not if you remember our squirrel episode, get that on 652 00:36:19,960 --> 00:36:21,560 Speaker 1: a shirt or a sticker. It's a great way to 653 00:36:21,600 --> 00:36:23,239 Speaker 1: support the show. And if you want to support the 654 00:36:23,239 --> 00:36:25,360 Speaker 1: show in a way it doesn't cost you a dime. 655 00:36:25,719 --> 00:36:27,840 Speaker 1: Just simply rate and review us wherever you have the 656 00:36:27,880 --> 00:36:30,040 Speaker 1: power to do so, and don't forget about Invention. The 657 00:36:30,080 --> 00:36:33,440 Speaker 1: Invention Podcast, the new show that Joe and I have 658 00:36:33,440 --> 00:36:36,520 Speaker 1: have put out coming out every Monday about human techno 659 00:36:36,640 --> 00:36:39,640 Speaker 1: history and the power of invention. Big thanks as always 660 00:36:39,640 --> 00:36:43,240 Speaker 1: to our excellent audio producers Alex Williams and try Harrison. 661 00:36:43,600 --> 00:36:45,080 Speaker 1: If you would like to get in touch with us 662 00:36:45,160 --> 00:36:47,560 Speaker 1: directly to let us know feedback on this episode or 663 00:36:47,600 --> 00:36:50,040 Speaker 1: any other, to suggest a topic for the future, or 664 00:36:50,080 --> 00:36:52,319 Speaker 1: just to say hi, you can always email us at 665 00:36:52,440 --> 00:37:04,680 Speaker 1: blow the Mind at how stuff works dot com for 666 00:37:04,800 --> 00:37:07,120 Speaker 1: more on this and thousands of other topics. Does it 667 00:37:07,200 --> 00:37:20,000 Speaker 1: how stuff works dot com? I think the differ