1 00:00:03,040 --> 00:00:05,360 Speaker 1: Welcome to Stuff to Blow Your Mind production of My 2 00:00:05,480 --> 00:00:14,920 Speaker 1: Heart Radio. Hey you welcome to Stuff to Blow your Mind. 3 00:00:15,080 --> 00:00:18,239 Speaker 1: My name is Robert Lamb and I'm Joe McCormick. And 4 00:00:18,640 --> 00:00:21,200 Speaker 1: for the next few episodes we're going to be doing 5 00:00:21,320 --> 00:00:25,520 Speaker 1: a series on a symmetry. And to introduce this series, 6 00:00:25,600 --> 00:00:28,400 Speaker 1: I wanted to talk a little bit about a favorite 7 00:00:28,440 --> 00:00:31,639 Speaker 1: animal of ours, the nar wall. Yes, the what is it, 8 00:00:31,680 --> 00:00:34,800 Speaker 1: the corpse whale um of of the ocean, the unicorn 9 00:00:34,840 --> 00:00:37,800 Speaker 1: of the sea. Right, yeah, so corpse whale. That's literally 10 00:00:37,800 --> 00:00:41,360 Speaker 1: what its name means, whale of course wall, but nar 11 00:00:42,479 --> 00:00:45,080 Speaker 1: meaning corpse. So yeah, it's like a dead body whale, 12 00:00:45,440 --> 00:00:48,040 Speaker 1: having to do with its gray and modeled appearance as 13 00:00:48,080 --> 00:00:50,520 Speaker 1: it sort of floats around near the top of the water. 14 00:00:50,800 --> 00:00:53,360 Speaker 1: But the more famous feature of this whale, apart from 15 00:00:53,400 --> 00:00:57,560 Speaker 1: looking like a corpse, is its horn or tusk or 16 00:00:58,080 --> 00:01:00,760 Speaker 1: we can dispute what's the best word to use for 17 00:01:00,840 --> 00:01:02,840 Speaker 1: it here, but yeah, as you say, it is the 18 00:01:02,920 --> 00:01:05,959 Speaker 1: unicorn of the polar seas. So the nor wall is 19 00:01:06,000 --> 00:01:10,120 Speaker 1: a medium sized Arctic marine mammal in the suborder of 20 00:01:10,280 --> 00:01:14,959 Speaker 1: toothed whales or Odonto ceti. And it is immediately recognizable 21 00:01:15,000 --> 00:01:18,560 Speaker 1: because most males of the nar walls, and occasionally some 22 00:01:18,600 --> 00:01:23,000 Speaker 1: females as well, possess a giant spike or tusk growing 23 00:01:23,200 --> 00:01:26,920 Speaker 1: straight out of their faces. And this tusk can grow 24 00:01:26,959 --> 00:01:30,640 Speaker 1: absurdly long, up to about three meters or ten feet, 25 00:01:31,319 --> 00:01:35,880 Speaker 1: and the orientation of this tusk looks very unusual compared 26 00:01:35,880 --> 00:01:38,080 Speaker 1: to most other mammals. So you think about other mammals 27 00:01:38,080 --> 00:01:41,000 Speaker 1: with horns or tusks. Uh, you might think about bo 28 00:01:41,120 --> 00:01:43,440 Speaker 1: vines in which the horns rise up off the top 29 00:01:43,480 --> 00:01:46,240 Speaker 1: of the head, or you might think about the rhinoceros 30 00:01:46,240 --> 00:01:48,400 Speaker 1: where it points up from the end of the snouts 31 00:01:48,680 --> 00:01:51,480 Speaker 1: kind of you know, up from the ground. Or you 32 00:01:51,520 --> 00:01:54,320 Speaker 1: might think about the tusks of a bore an elephant 33 00:01:54,400 --> 00:01:56,360 Speaker 1: kind of coming out of the mouth at an angle. 34 00:01:57,000 --> 00:02:00,160 Speaker 1: But but no, in the In the narwhall, you have 35 00:02:00,400 --> 00:02:03,200 Speaker 1: a whales body, which again is a sort of modeled 36 00:02:03,240 --> 00:02:06,000 Speaker 1: gray tube that can grow about four to five meters 37 00:02:06,160 --> 00:02:10,639 Speaker 1: long in adulthood, and then the tusk just juts straight 38 00:02:10,680 --> 00:02:13,560 Speaker 1: out of the face, adding another three ms or so 39 00:02:13,800 --> 00:02:16,079 Speaker 1: or up to another three ms or so in length. 40 00:02:16,520 --> 00:02:19,240 Speaker 1: So when the tusk is present, the animal is sort 41 00:02:19,280 --> 00:02:22,359 Speaker 1: of shaped like a dart. Or like a spear. Now, 42 00:02:22,400 --> 00:02:24,200 Speaker 1: when we've talked about in Our Walls before, I think, 43 00:02:24,280 --> 00:02:27,800 Speaker 1: especially in our episodes on the unicorn legend, uh, we 44 00:02:27,800 --> 00:02:32,240 Speaker 1: we talked a lot about the theories behind the origin 45 00:02:32,320 --> 00:02:34,880 Speaker 1: and the purpose of the tusk. We're not going to 46 00:02:34,919 --> 00:02:38,200 Speaker 1: completely rehash that discussion here, though, I did want to 47 00:02:38,240 --> 00:02:42,079 Speaker 1: note a development which was in a more recent paper 48 00:02:42,120 --> 00:02:45,080 Speaker 1: I came across addressing the biological function of the tusk. 49 00:02:45,200 --> 00:02:48,720 Speaker 1: So a long running question for marine biologists who study 50 00:02:48,760 --> 00:02:52,400 Speaker 1: the nar wall is why this giant tusk it's it 51 00:02:52,560 --> 00:02:55,519 Speaker 1: looks very unwieldy. What is it for? What is the 52 00:02:55,560 --> 00:02:59,720 Speaker 1: evolutionary justification? And this can be difficult to study because 53 00:02:59,840 --> 00:03:03,160 Speaker 1: it is not a trivial task to go out and 54 00:03:03,200 --> 00:03:06,000 Speaker 1: just observed in our walls. In the wild, not only 55 00:03:06,040 --> 00:03:09,720 Speaker 1: do they live underwater, but they live under the Arctic ice. 56 00:03:10,040 --> 00:03:12,760 Speaker 1: So they remain veiled in a great deal of mystery. 57 00:03:13,160 --> 00:03:16,000 Speaker 1: But we're not without some clues. And I guess the 58 00:03:16,040 --> 00:03:19,120 Speaker 1: place to start is that the tusk looks so threatening 59 00:03:19,160 --> 00:03:22,240 Speaker 1: to the naive human brain that we immediately want to 60 00:03:22,240 --> 00:03:24,079 Speaker 1: say it is a weapon, right, you know, it is 61 00:03:24,120 --> 00:03:26,720 Speaker 1: a spear, It is a dark that That's what I 62 00:03:26,800 --> 00:03:29,920 Speaker 1: without even thinking about it compared the animal too, right, right, 63 00:03:30,000 --> 00:03:32,520 Speaker 1: you think of it being some sort of a javelin 64 00:03:32,639 --> 00:03:36,120 Speaker 1: or spear um harpoon on the front of this, uh, 65 00:03:36,200 --> 00:03:39,040 Speaker 1: this whale that it's using to to skewer things, or 66 00:03:39,080 --> 00:03:42,680 Speaker 1: that it's using this to sort of fence with other whales. Yeah, 67 00:03:42,680 --> 00:03:44,840 Speaker 1: so you think it must be for you know, stabbing 68 00:03:44,880 --> 00:03:48,360 Speaker 1: sharks or skewering fish prey or something. Though it's funny 69 00:03:48,400 --> 00:03:51,160 Speaker 1: that people think, oh, yeah, it's for for skewering fish 70 00:03:51,200 --> 00:03:53,840 Speaker 1: that they're going to eat. But if that were true, 71 00:03:54,040 --> 00:03:56,040 Speaker 1: wouldn't that be a little awkward? Like how would it 72 00:03:56,080 --> 00:03:59,680 Speaker 1: get the fish to its mouth after that? Like you 73 00:03:59,680 --> 00:04:03,760 Speaker 1: would normally you don't need a stab and then eat. 74 00:04:03,880 --> 00:04:06,000 Speaker 1: If you're a whale, you just eat, You just bite 75 00:04:06,000 --> 00:04:09,240 Speaker 1: and then swallow. Anyway, there have been some accounts of 76 00:04:09,240 --> 00:04:12,440 Speaker 1: what appeared to be various offensive uses of the tusk, 77 00:04:13,080 --> 00:04:16,320 Speaker 1: but these might be coincidental or secondary behaviors. And then 78 00:04:16,320 --> 00:04:20,440 Speaker 1: there are all other odd proposals, including things like stabbing 79 00:04:20,480 --> 00:04:23,960 Speaker 1: through surface ice to create holes for breathing. Of course, 80 00:04:24,000 --> 00:04:26,839 Speaker 1: remember the nar walls and air breathing mammal, but the 81 00:04:26,880 --> 00:04:29,760 Speaker 1: fact that the tusk is hollow and filled with sensitive 82 00:04:29,800 --> 00:04:33,480 Speaker 1: nerve endings, has led some researchers to believe it is 83 00:04:33,520 --> 00:04:36,520 Speaker 1: a sensory organ and there there is some evidence that 84 00:04:36,600 --> 00:04:39,039 Speaker 1: it can be used for gathering and even potentially for 85 00:04:39,240 --> 00:04:45,000 Speaker 1: sharing information about the characteristics of seawater, maybe things like temperature, salinity, 86 00:04:45,040 --> 00:04:48,960 Speaker 1: and so forth. However, one of the most important clues 87 00:04:49,000 --> 00:04:52,719 Speaker 1: about the primary evolutionary justification of the tusk is the 88 00:04:52,760 --> 00:04:56,960 Speaker 1: fact of sexual dimorphism. So the tusks are almost always 89 00:04:57,160 --> 00:05:00,760 Speaker 1: found in males, and one obvious conclud lusion from this 90 00:05:00,880 --> 00:05:05,039 Speaker 1: is that the tusk can't be necessary for survival, or 91 00:05:05,080 --> 00:05:07,240 Speaker 1: else females would have them as well. Right, so it 92 00:05:07,279 --> 00:05:12,680 Speaker 1: can't provide a major individual survival advantage, or else you'd 93 00:05:12,680 --> 00:05:15,320 Speaker 1: expect all individuals to have them, or we would at 94 00:05:15,360 --> 00:05:18,680 Speaker 1: least observe, uh, you know, the the whales that have 95 00:05:18,800 --> 00:05:21,960 Speaker 1: them out competing the other one the ones that don't 96 00:05:21,960 --> 00:05:24,760 Speaker 1: have them in survival, which is not the case. So 97 00:05:24,880 --> 00:05:27,159 Speaker 1: one of the leading theories then is that it's a 98 00:05:27,240 --> 00:05:31,000 Speaker 1: sexually selected trade. It's a body feature without a major 99 00:05:31,200 --> 00:05:35,120 Speaker 1: role in survival, which grows very prominent in males because 100 00:05:35,240 --> 00:05:39,520 Speaker 1: it increases reproductive success, maybe by being more appealing to 101 00:05:39,600 --> 00:05:42,720 Speaker 1: female in our walls, or maybe by causing rival males 102 00:05:42,760 --> 00:05:45,560 Speaker 1: to stay away and so forth and anyway. As so, 103 00:05:45,720 --> 00:05:48,800 Speaker 1: the recent paper I found was one by Graham at 104 00:05:48,800 --> 00:05:52,080 Speaker 1: All published in Biology Letters called the longer the Better 105 00:05:52,240 --> 00:05:57,640 Speaker 1: evidence that narwhal tusks are sexually selected. This was from 106 00:05:57,680 --> 00:06:00,479 Speaker 1: and of course this paper acknowledges that it's really difficult 107 00:06:00,520 --> 00:06:02,520 Speaker 1: to study nar walls in the wild to figure out 108 00:06:02,560 --> 00:06:05,520 Speaker 1: what the tusk is for, so instead it asks if 109 00:06:05,560 --> 00:06:09,560 Speaker 1: we can infer anything about tusk function from examining the 110 00:06:09,640 --> 00:06:13,400 Speaker 1: natural variation in narwhal tusk measurements that have been taken 111 00:06:13,440 --> 00:06:16,080 Speaker 1: over the course of the last thirty five years. And 112 00:06:16,160 --> 00:06:21,000 Speaker 1: so their sample comprised two D forty five individual adult males, 113 00:06:21,040 --> 00:06:23,760 Speaker 1: and based on these measurements, the authors conclude that the 114 00:06:23,800 --> 00:06:28,080 Speaker 1: evidence does suggest the primary driver of tusk evolution is 115 00:06:28,120 --> 00:06:32,440 Speaker 1: sexual selection. Quote. By combining our results on tusk scaling 116 00:06:32,839 --> 00:06:36,000 Speaker 1: with known material properties of the tusk, we suggest that 117 00:06:36,000 --> 00:06:38,960 Speaker 1: the narwhal tusk is a sexually selected signal that is 118 00:06:39,040 --> 00:06:43,559 Speaker 1: used during male male contests. So how would you conclude this? Well, 119 00:06:44,080 --> 00:06:48,680 Speaker 1: the tusk demonstrates a growth pattern known as hyper alimentary, 120 00:06:48,760 --> 00:06:52,080 Speaker 1: which means a body feature that grows faster than the 121 00:06:52,080 --> 00:06:56,560 Speaker 1: body as a whole. So, for example, most body features 122 00:06:56,640 --> 00:07:01,040 Speaker 1: are roughly alometric. They're linearly allometrics. They grow in size 123 00:07:01,120 --> 00:07:03,880 Speaker 1: proportional to the rest of the body. If your body 124 00:07:03,960 --> 00:07:07,800 Speaker 1: is bigger overall, you probably also have longer shin bones 125 00:07:07,880 --> 00:07:11,760 Speaker 1: and larger hands and so forth. Some features might be 126 00:07:11,960 --> 00:07:16,760 Speaker 1: hypo allometric or you know, sublimetric, they grow less than 127 00:07:16,800 --> 00:07:21,120 Speaker 1: the body as a whole. But narwhal tusks are hyper alometric. 128 00:07:21,240 --> 00:07:25,480 Speaker 1: In the largest individuals, the tusks grow longer than simple 129 00:07:25,560 --> 00:07:28,760 Speaker 1: linear scaling would predict. So they're not just big in 130 00:07:28,840 --> 00:07:31,800 Speaker 1: proportion to the rest of the body, they're way bigger 131 00:07:31,800 --> 00:07:36,560 Speaker 1: than that. There they just they get ridiculously huge. And 132 00:07:36,640 --> 00:07:39,920 Speaker 1: so this is not proof, but it is characteristic of 133 00:07:40,000 --> 00:07:43,240 Speaker 1: traits that are sexually selected. And the authors write in 134 00:07:43,240 --> 00:07:47,480 Speaker 1: their conclusion quote, sexually selected signals used in mail mail 135 00:07:47,560 --> 00:07:51,800 Speaker 1: competition are more likely to exhibit hyper elimetry when compared 136 00:07:51,840 --> 00:07:56,080 Speaker 1: to other sexually selected traits. Because the information being signaled 137 00:07:56,160 --> 00:08:00,000 Speaker 1: is simple, I am bigger than you. To convey this message, 138 00:08:00,040 --> 00:08:03,280 Speaker 1: males exaggerate the size of their signals, which facilitate the 139 00:08:03,320 --> 00:08:08,520 Speaker 1: detection of size discrepancies. Between individuals, reducing the likelihood of 140 00:08:08,600 --> 00:08:12,960 Speaker 1: engaging in potentially dangerous fights, and they note that this 141 00:08:13,040 --> 00:08:16,720 Speaker 1: could explain the so called tusking behavior that's been observed, 142 00:08:17,080 --> 00:08:20,800 Speaker 1: where male narwhales sometimes appear to be crossing tusks are 143 00:08:20,800 --> 00:08:25,160 Speaker 1: almost like dueling with their tusks um, which could actually 144 00:08:25,160 --> 00:08:27,880 Speaker 1: be not a form of fighting, but a way for 145 00:08:28,000 --> 00:08:31,160 Speaker 1: the animals to compare the size of their tusks in 146 00:08:31,280 --> 00:08:35,680 Speaker 1: order to avoid a fight. So, in an interesting twist, 147 00:08:35,760 --> 00:08:38,520 Speaker 1: it could be the case that our naive intuition that 148 00:08:38,600 --> 00:08:42,520 Speaker 1: this tusk is a weapon is true in a sense, 149 00:08:42,679 --> 00:08:47,839 Speaker 1: but it's a weapon designed specifically to look scary because 150 00:08:48,000 --> 00:08:52,319 Speaker 1: it will discourage actual fighting between males and sexual competition 151 00:08:52,559 --> 00:08:55,800 Speaker 1: most of the time. So it's you know, two rival 152 00:08:55,840 --> 00:08:58,840 Speaker 1: males are are competing for a chance to mate, and 153 00:08:58,920 --> 00:09:01,080 Speaker 1: one of them goes, wow, that that other one's tusk 154 00:09:01,200 --> 00:09:04,199 Speaker 1: is absurdly long. No need to fight this out, my mistakes, 155 00:09:04,240 --> 00:09:07,320 Speaker 1: see you later. Now. They say that the existing evidence 156 00:09:07,320 --> 00:09:10,079 Speaker 1: sort of points us in this direction, but it's not conclusive. 157 00:09:10,120 --> 00:09:13,480 Speaker 1: Their alternate explanations. Maybe the large tusk plays a role 158 00:09:13,520 --> 00:09:18,080 Speaker 1: in mate choice itself. Maybe females prefer males with larger tusks, 159 00:09:19,520 --> 00:09:21,760 Speaker 1: but they're in general, there's still just a lot we 160 00:09:21,760 --> 00:09:23,800 Speaker 1: don't know about these animals, so so the book is 161 00:09:23,840 --> 00:09:27,760 Speaker 1: not completely closed on this question. And it's also possible 162 00:09:27,840 --> 00:09:31,040 Speaker 1: that the tusk has multiple secondary functions, for example, as 163 00:09:31,040 --> 00:09:33,920 Speaker 1: a sensory organ like we talked about earlier. Though again, 164 00:09:33,960 --> 00:09:36,840 Speaker 1: as I mentioned earlier, that those secondary functions can't be 165 00:09:36,960 --> 00:09:40,640 Speaker 1: all that crucial for survival or we would see that, 166 00:09:40,840 --> 00:09:42,360 Speaker 1: you know, we would see that playing out in nar 167 00:09:42,400 --> 00:09:44,840 Speaker 1: whale populations, the ones with the tusks would be more 168 00:09:44,880 --> 00:09:48,160 Speaker 1: likely to survive, and that's not what we find now. 169 00:09:48,200 --> 00:09:50,679 Speaker 1: To bring it back to the reason I wanted to 170 00:09:50,720 --> 00:09:54,560 Speaker 1: talk about narwhals in today's episode, you may remember one 171 00:09:54,640 --> 00:09:58,080 Speaker 1: strange fact about the narwhal's tusk from our previous episodes 172 00:09:58,120 --> 00:10:01,440 Speaker 1: where these animals came up, and it's that the normals 173 00:10:01,520 --> 00:10:05,920 Speaker 1: tusk is not an external caratinous horn like that of 174 00:10:05,960 --> 00:10:11,120 Speaker 1: the rhinoceros. Instead, it is a tooth. And I don't 175 00:10:11,160 --> 00:10:13,520 Speaker 1: just mean it is made out of the same stuff 176 00:10:13,559 --> 00:10:16,560 Speaker 1: as a tooth. It is literally a tooth. It is 177 00:10:16,600 --> 00:10:20,360 Speaker 1: a tooth from the upper jaw that has been repurposed 178 00:10:20,360 --> 00:10:24,400 Speaker 1: by evolution to grow into a tusk. By changing the 179 00:10:24,480 --> 00:10:28,960 Speaker 1: orientation of growth so that it grows straight out forward forward, 180 00:10:29,000 --> 00:10:32,400 Speaker 1: out of the jaw and then erupts from the flesh 181 00:10:32,520 --> 00:10:35,640 Speaker 1: of the face. It literally grows through the flesh of 182 00:10:35,640 --> 00:10:39,120 Speaker 1: the upper lip and then continues growing rapidly, and as 183 00:10:39,160 --> 00:10:43,640 Speaker 1: we've seen, even hyper elemetrically. But here's what I've been 184 00:10:43,679 --> 00:10:46,360 Speaker 1: getting hung up on. The nor Wals tusk is not 185 00:10:46,440 --> 00:10:50,040 Speaker 1: only a tooth. In almost all cases, it is the 186 00:10:50,360 --> 00:10:56,520 Speaker 1: left canine, the left maxillary canine tooth having erupted from 187 00:10:56,600 --> 00:10:59,240 Speaker 1: the upper lip. And this is this is certainly something 188 00:10:59,280 --> 00:11:01,400 Speaker 1: when you learn for the first time it does it 189 00:11:01,440 --> 00:11:03,680 Speaker 1: does feel a little bit wrong. I mean, a number 190 00:11:03,720 --> 00:11:06,559 Speaker 1: of these these factoids about the norwell perhaps feel a 191 00:11:06,600 --> 00:11:09,439 Speaker 1: little wrong, you know, because ultimately it's just a far 192 00:11:09,559 --> 00:11:13,840 Speaker 1: weirder and perhaps sillier animal than than most of us assumed. 193 00:11:14,080 --> 00:11:17,600 Speaker 1: It is not silly, is deadly serious, but it does 194 00:11:17,720 --> 00:11:20,400 Speaker 1: have one tooth just poking out of its lip for 195 00:11:20,640 --> 00:11:23,080 Speaker 1: I don't know, ten feet. But you're not allowed to laugh, 196 00:11:23,559 --> 00:11:27,360 Speaker 1: um so, But yeah, anyway, So, to quote from a 197 00:11:27,400 --> 00:11:33,000 Speaker 1: paper from in the Anatomical Record by Nuilla at all quote, 198 00:11:33,120 --> 00:11:37,360 Speaker 1: males usually exhibit an erupted tusk on the left side 199 00:11:37,920 --> 00:11:41,360 Speaker 1: and an unerupted embedded tusk on the right. So it's 200 00:11:41,360 --> 00:11:43,880 Speaker 1: got two of these teeth. It's got, you know, that's symmetrical. 201 00:11:43,920 --> 00:11:48,079 Speaker 1: There's one on each side, except usually one just kind 202 00:11:48,080 --> 00:11:49,959 Speaker 1: of grows a little bit and then stays inside the 203 00:11:50,040 --> 00:11:52,520 Speaker 1: upper jaw and doesn't do anything, while the other one 204 00:11:53,120 --> 00:11:56,240 Speaker 1: breaks through the skin and grows up to ten feet long. 205 00:11:56,679 --> 00:12:00,520 Speaker 1: So that's what you usually see. But then the quote continues, 206 00:12:00,559 --> 00:12:05,000 Speaker 1: whereas females usually have two embedded tusks, neither erupting. Other 207 00:12:05,120 --> 00:12:09,520 Speaker 1: less common expressions of narwhal dentition include males with two tusks, 208 00:12:09,559 --> 00:12:12,880 Speaker 1: males with two embedded tusks so neither one comes out, 209 00:12:13,320 --> 00:12:17,520 Speaker 1: females with one erupted and one embedded tusk, and females 210 00:12:17,559 --> 00:12:20,520 Speaker 1: with two erupted tusks. And I checked. I think there's 211 00:12:20,559 --> 00:12:23,680 Speaker 1: only been one documented case of the ladder of the 212 00:12:23,760 --> 00:12:27,200 Speaker 1: females with two tusks coming out. But the authors of 213 00:12:27,200 --> 00:12:30,360 Speaker 1: this paper do extensive analysis to confirm that these are 214 00:12:30,400 --> 00:12:33,600 Speaker 1: not horns, they are teeth, and they figure out exactly 215 00:12:33,640 --> 00:12:36,280 Speaker 1: what teeth they are. They are the upper canines, and 216 00:12:36,600 --> 00:12:41,240 Speaker 1: in almost all cases, the left upper canine. Now I 217 00:12:41,280 --> 00:12:42,920 Speaker 1: don't know if I'm alone in this, but I am 218 00:12:43,080 --> 00:12:45,400 Speaker 1: just as struck by the fact that the tusk is 219 00:12:45,400 --> 00:12:48,960 Speaker 1: actually the left canine as I am about the fact 220 00:12:49,000 --> 00:12:52,320 Speaker 1: that it's a tooth to begin with. Why the left canine, 221 00:12:53,200 --> 00:12:57,200 Speaker 1: As the paper mentions, narwhal's occasionally have two erupted tusks, 222 00:12:57,280 --> 00:12:59,840 Speaker 1: two tusks of about the same length coming out to 223 00:13:00,000 --> 00:13:02,839 Speaker 1: other It's rare, but you find some like that, And 224 00:13:02,960 --> 00:13:05,920 Speaker 1: if you see pictures of the narwhals with two tusks, 225 00:13:06,440 --> 00:13:09,760 Speaker 1: they look much more appropriate to the preferences of nature. 226 00:13:09,840 --> 00:13:12,000 Speaker 1: You can look up images of this online. In fact, 227 00:13:12,040 --> 00:13:15,480 Speaker 1: even though they're much more rare in the wild. Uh. 228 00:13:15,520 --> 00:13:18,600 Speaker 1: A lot of the images of narwhal skulls have two tusks. 229 00:13:18,640 --> 00:13:22,000 Speaker 1: I guess because the rare ones get photographed more often. Well, 230 00:13:22,040 --> 00:13:24,400 Speaker 1: I mean, I guess. On one hand, the left handed 231 00:13:24,440 --> 00:13:27,800 Speaker 1: side is the sinister side the sinstral side. So if 232 00:13:28,000 --> 00:13:31,000 Speaker 1: you're going to have a crazy, super long tooth emerged 233 00:13:31,000 --> 00:13:34,839 Speaker 1: from your face and maybe the sinister side makes sense, well, 234 00:13:34,880 --> 00:13:38,319 Speaker 1: that's just your twisted mind working. It's it's fancy. I mean, no, 235 00:13:38,840 --> 00:13:42,800 Speaker 1: come on, like the two tusks, they look more like 236 00:13:42,880 --> 00:13:46,040 Speaker 1: something that you would just buy intuition expect to find 237 00:13:46,080 --> 00:13:49,080 Speaker 1: in the ocean, much more so than the common one 238 00:13:49,160 --> 00:13:51,360 Speaker 1: tusk skull, which when I see it, I mean, it 239 00:13:51,520 --> 00:13:56,760 Speaker 1: is beautiful, but it also it looks unbalanced and wrong. Though. 240 00:13:56,760 --> 00:13:59,080 Speaker 1: I will say that the two tusks or wall, if 241 00:13:59,080 --> 00:14:03,280 Speaker 1: you look up images of specimens of this creature like 242 00:14:03,360 --> 00:14:06,720 Speaker 1: this one is perplexing as well because it kind of 243 00:14:06,760 --> 00:14:11,960 Speaker 1: it doesn't form um. They're not perfectly parallel to each other. 244 00:14:12,200 --> 00:14:15,640 Speaker 1: It creates kind of a V shape that is a 245 00:14:15,640 --> 00:14:19,760 Speaker 1: little confusing and certainly makes you lean more into possibilities. Yeah, 246 00:14:19,760 --> 00:14:23,640 Speaker 1: that this is not about stabbing or using these uh 247 00:14:23,640 --> 00:14:27,200 Speaker 1: these tusks for some sort of a a physical practical use, 248 00:14:27,280 --> 00:14:30,880 Speaker 1: but something else like that they look more like communications 249 00:14:30,960 --> 00:14:33,200 Speaker 1: array when you see two of them as opposed to 250 00:14:33,200 --> 00:14:35,880 Speaker 1: just one. Well, yeah, I think having two of them 251 00:14:35,960 --> 00:14:40,000 Speaker 1: even further highlights that these are obviously not practically useful 252 00:14:40,120 --> 00:14:42,960 Speaker 1: for something like like catching prey or eating you know, 253 00:14:43,040 --> 00:14:44,800 Speaker 1: you just you look at that and it's like, how 254 00:14:44,840 --> 00:14:47,320 Speaker 1: how's that going to work? And it's obviously they're not 255 00:14:47,480 --> 00:14:50,240 Speaker 1: using it for that, at least not most of the time. 256 00:14:50,720 --> 00:14:53,040 Speaker 1: I know. There are these little anecdotes of somebody saying 257 00:14:53,040 --> 00:14:54,920 Speaker 1: that you know, they saw a nar wall like tap 258 00:14:54,920 --> 00:14:57,280 Speaker 1: a fish with a tusk or something, so maybe, but 259 00:14:57,840 --> 00:15:00,000 Speaker 1: that that clearly does not appear to be a prime 260 00:15:00,080 --> 00:15:02,680 Speaker 1: very use of them. But I wanted to come back 261 00:15:02,720 --> 00:15:06,560 Speaker 1: to the idea that it looks it looks wrong at 262 00:15:06,600 --> 00:15:08,440 Speaker 1: least even though of course you know this is what 263 00:15:08,560 --> 00:15:12,320 Speaker 1: evolution selected. It is, uh, it is right for something, 264 00:15:12,600 --> 00:15:16,120 Speaker 1: it has a use, but it looks wrong to our brains, 265 00:15:16,240 --> 00:15:18,880 Speaker 1: and so it causes you to ask the question, well, 266 00:15:18,920 --> 00:15:21,920 Speaker 1: first of all, why is it that evolution drove the 267 00:15:22,000 --> 00:15:25,480 Speaker 1: narwhall to be unbalanced in this way? And and second, 268 00:15:25,640 --> 00:15:29,280 Speaker 1: why is it that my intuition tells me incorrectly that 269 00:15:29,360 --> 00:15:32,440 Speaker 1: a long, single tusk should not emerge from the socket 270 00:15:32,520 --> 00:15:36,800 Speaker 1: of the left maxillary canine, like if an animal has 271 00:15:36,880 --> 00:15:38,920 Speaker 1: one tusk, it should come out of a hole right 272 00:15:38,960 --> 00:15:41,240 Speaker 1: in the middle. And so this is going to be 273 00:15:41,280 --> 00:15:43,280 Speaker 1: the beginning of a series of episodes. We're gonna do 274 00:15:43,320 --> 00:15:45,960 Speaker 1: at least two maybe more. What we'll see, uh, but 275 00:15:46,080 --> 00:15:49,200 Speaker 1: there will be on a symmetry in the animal world 276 00:15:49,280 --> 00:15:53,320 Speaker 1: when an animal's left and right do not match. So 277 00:15:53,360 --> 00:15:56,600 Speaker 1: in future episodes we will we will explore some theoretical 278 00:15:56,720 --> 00:16:02,000 Speaker 1: questions about about embryonic developed meant and how animal asymmetry 279 00:16:02,120 --> 00:16:06,320 Speaker 1: comes about. Uh, probably look at some crabs and other crustaceans. 280 00:16:06,320 --> 00:16:08,560 Speaker 1: But today I think we're gonna we're gonna look especially 281 00:16:08,600 --> 00:16:11,840 Speaker 1: at like whales and uh and other swimming creatures of 282 00:16:11,840 --> 00:16:15,600 Speaker 1: the sea, UH, and just generally highlights some interesting examples 283 00:16:15,640 --> 00:16:24,520 Speaker 1: of asymmetry in the natural world. Now, I think it's 284 00:16:24,560 --> 00:16:27,480 Speaker 1: important to acknowledge at the beginning that the kind of 285 00:16:27,920 --> 00:16:31,680 Speaker 1: symmetry or asymmetry we're talking about, the kind of symmetry 286 00:16:31,840 --> 00:16:35,920 Speaker 1: we expect to see in animals is only one specific 287 00:16:36,040 --> 00:16:40,520 Speaker 1: type of symmetry, called bilateral symmetry, and not all animals 288 00:16:40,520 --> 00:16:44,800 Speaker 1: actually possess it, even in an approximate sense. So bilateral 289 00:16:44,840 --> 00:16:48,160 Speaker 1: symmetry is actually a fairly restricted type of symmetry. There 290 00:16:48,160 --> 00:16:51,200 Speaker 1: are three dimensions of space, and if you plot a 291 00:16:51,280 --> 00:16:53,960 Speaker 1: human body on those three dimensions, you'll notice we are 292 00:16:54,000 --> 00:16:58,600 Speaker 1: actually only symmetrical along one of those three axes. So 293 00:16:58,720 --> 00:17:01,720 Speaker 1: on height, our head in our feet, of course, are 294 00:17:01,760 --> 00:17:05,720 Speaker 1: not mirror images of each other. On depth, we're also 295 00:17:05,800 --> 00:17:08,800 Speaker 1: not symmetrical. Our backs do not mirror our fronts. We 296 00:17:08,840 --> 00:17:12,240 Speaker 1: don't have faces or butts on both sides. It's only 297 00:17:12,280 --> 00:17:16,399 Speaker 1: across our width that you find approximate symmetry our left side. 298 00:17:16,520 --> 00:17:20,959 Speaker 1: Roughly mirrors are right side. And in three dimensional space, 299 00:17:21,119 --> 00:17:25,280 Speaker 1: the most perfectly symmetrical form is actually a sphere, since 300 00:17:25,320 --> 00:17:28,480 Speaker 1: if you divide a sphere in half along any plane 301 00:17:28,480 --> 00:17:32,920 Speaker 1: you want, no matter it's orientation, the two sides will match. Uh. 302 00:17:32,960 --> 00:17:35,320 Speaker 1: And I hesitate because I'm about to make a generalization 303 00:17:35,359 --> 00:17:38,160 Speaker 1: about geometry. I'm always afraid I'm gonna say something wrong there. 304 00:17:38,160 --> 00:17:40,040 Speaker 1: But I tried to look this up and confirm it. 305 00:17:40,560 --> 00:17:44,440 Speaker 1: I believe this is unique to the sphere, that all 306 00:17:44,440 --> 00:17:48,760 Speaker 1: other three D shapes can be bisected in ways where 307 00:17:48,880 --> 00:17:52,160 Speaker 1: the two halves may have equal volume but will not 308 00:17:52,280 --> 00:17:54,840 Speaker 1: match an outline. But if you cut a sphere in half, 309 00:17:55,160 --> 00:17:59,000 Speaker 1: it's always two perfect hemispheres, no matter what direction you 310 00:17:59,040 --> 00:18:02,000 Speaker 1: cut from. And this actually connects to a passage in 311 00:18:02,000 --> 00:18:05,760 Speaker 1: a book I came across by the mathematician Herman Vile 312 00:18:06,320 --> 00:18:09,960 Speaker 1: called Symmetry from Princeton University Press in nineteen fifty two, 313 00:18:10,480 --> 00:18:15,399 Speaker 1: and Vile is writing about about the history of association 314 00:18:15,560 --> 00:18:21,359 Speaker 1: between symmetry in the geometric sense and the concept of beauty. Uh. 315 00:18:21,480 --> 00:18:25,560 Speaker 1: You know, moral virtue, and perfection, and he writes quote 316 00:18:25,600 --> 00:18:29,600 Speaker 1: because of their complete rotational symmetry, the circle in the 317 00:18:29,600 --> 00:18:32,600 Speaker 1: plane and the sphere in space were considered by the 318 00:18:32,640 --> 00:18:38,680 Speaker 1: Pythagoreans the most perfect geometric figures, and Aristotle ascribed spherical 319 00:18:38,760 --> 00:18:43,200 Speaker 1: shape to the celestial bodies because any other would detract 320 00:18:43,400 --> 00:18:47,679 Speaker 1: from their heavenly perfection. Now it's interesting, knowing what we 321 00:18:47,720 --> 00:18:50,520 Speaker 1: know now about the cause of spherical objects in space, 322 00:18:51,000 --> 00:18:53,640 Speaker 1: namely gravity, right that as as the mass of an 323 00:18:53,640 --> 00:18:58,119 Speaker 1: object increases, it tends to become more and more perfectly spherical, 324 00:18:58,520 --> 00:19:00,920 Speaker 1: with the I guess the end point of that being 325 00:19:00,960 --> 00:19:04,280 Speaker 1: that a black hole theoretically is pretty much perfectly spherical, 326 00:19:04,600 --> 00:19:07,960 Speaker 1: whereas smaller objects in space, because gravity is not as 327 00:19:07,960 --> 00:19:11,080 Speaker 1: strong a force on the on the smoothing of their 328 00:19:11,080 --> 00:19:13,639 Speaker 1: outer edges, they can have more irregular shapes. This is 329 00:19:13,640 --> 00:19:17,520 Speaker 1: why you get irregular potato shaped comets and asteroids. But 330 00:19:17,680 --> 00:19:19,680 Speaker 1: you know, you start getting up into planet size and 331 00:19:20,000 --> 00:19:23,399 Speaker 1: you move closer and closer to spherical perfection. But anyway, 332 00:19:23,480 --> 00:19:26,560 Speaker 1: Vile goes on to quote a poet named Anna Wickham, 333 00:19:26,600 --> 00:19:30,000 Speaker 1: which was actually the pseudonym of a modernist poet named 334 00:19:30,119 --> 00:19:35,000 Speaker 1: Edith Alice Mary Harper uh in connecting the idea of 335 00:19:35,240 --> 00:19:40,720 Speaker 1: symmetry to God or the divine being, so Wickham rights quote, God, 336 00:19:40,880 --> 00:19:43,840 Speaker 1: thou great symmetry, who put a biting lust in me? 337 00:19:44,000 --> 00:19:47,399 Speaker 1: From whence my sorrow spring for all my frittered days 338 00:19:47,480 --> 00:19:50,640 Speaker 1: that I have spent in shapeless ways, Give me one 339 00:19:50,720 --> 00:19:54,840 Speaker 1: perfect thing, and then vile rights. Symmetry, as wide or 340 00:19:54,880 --> 00:19:57,760 Speaker 1: as narrow as you may define its meaning, is one 341 00:19:57,800 --> 00:20:00,399 Speaker 1: idea by which man, through the ages has tried to 342 00:20:00,480 --> 00:20:06,200 Speaker 1: comprehend and create order. Beauty and perfection. And equating symmetry 343 00:20:06,240 --> 00:20:09,600 Speaker 1: with beauty, goodness and perfection and even divinity can be 344 00:20:09,680 --> 00:20:13,480 Speaker 1: found all throughout literature. I think of Blake's The Tiger. 345 00:20:13,560 --> 00:20:17,320 Speaker 1: You know what immortal hander eye could frame thy fearful symmetry. 346 00:20:17,480 --> 00:20:19,400 Speaker 1: I guess it makes you want to say symmetry there, 347 00:20:20,119 --> 00:20:23,480 Speaker 1: But this clearly is has not just a geometric meaning, 348 00:20:23,520 --> 00:20:25,639 Speaker 1: where you will the two halves of the tiger do 349 00:20:25,840 --> 00:20:28,280 Speaker 1: match one another roughly because it is an animal with 350 00:20:28,320 --> 00:20:32,119 Speaker 1: bilateral symmetry, but that it means something more than that. 351 00:20:32,240 --> 00:20:36,879 Speaker 1: Symmetry here is in some sense synonymous with greatness or divinity. Yeah, 352 00:20:36,960 --> 00:20:39,600 Speaker 1: it's so that the tiger is is a perfect organism 353 00:20:39,680 --> 00:20:43,720 Speaker 1: and Blake's I here, um yeah, And you know, I 354 00:20:43,760 --> 00:20:48,040 Speaker 1: can be said about our obsession with with symmetry to 355 00:20:48,200 --> 00:20:51,199 Speaker 1: the point where it's like a flawed obsession with it. 356 00:20:51,359 --> 00:20:54,880 Speaker 1: Like we think that we want, say, perfectly symmetrical faces, 357 00:20:55,359 --> 00:20:59,000 Speaker 1: when most faces are certainly not a symmetrical And if 358 00:20:59,040 --> 00:21:02,359 Speaker 1: you take even famous and you know, often held up 359 00:21:02,400 --> 00:21:05,920 Speaker 1: his beautiful faces and you do the trick of creating 360 00:21:05,920 --> 00:21:08,439 Speaker 1: a symmetrical symmetrical face out of it, it's going to 361 00:21:08,480 --> 00:21:10,920 Speaker 1: look wrong to your eyes. It may it may look 362 00:21:11,000 --> 00:21:13,800 Speaker 1: very well look unnatural. Well. The the whole quest for 363 00:21:13,880 --> 00:21:18,000 Speaker 1: symmetry in in aesthetic beauty um is one of those 364 00:21:18,040 --> 00:21:21,720 Speaker 1: where it's like there's almost a kind of inverse uncanny valley. 365 00:21:21,760 --> 00:21:25,000 Speaker 1: It seems like people's natural preferences or something that tends 366 00:21:25,200 --> 00:21:28,400 Speaker 1: very close to symmetry. But then if you get right 367 00:21:28,480 --> 00:21:30,760 Speaker 1: up to it and go to actual symmetry, it's like, 368 00:21:30,760 --> 00:21:33,520 Speaker 1: oh no, no, no, that that looks all wrong. So 369 00:21:33,560 --> 00:21:35,480 Speaker 1: you want to be like right in the zone where 370 00:21:35,480 --> 00:21:40,240 Speaker 1: you're approaching symmetry, but not there. Yeah, though there, Certainly 371 00:21:40,240 --> 00:21:42,280 Speaker 1: when you get into design it gets it gets weird 372 00:21:42,320 --> 00:21:47,720 Speaker 1: because take airplanes, for example, airplanes tend to look best 373 00:21:47,760 --> 00:21:51,000 Speaker 1: to our I when they are perfectly symmetrical, and then 374 00:21:51,119 --> 00:21:53,320 Speaker 1: there are various reasons for that. And if you see 375 00:21:53,840 --> 00:21:56,800 Speaker 1: an asymmetrical airplane, and there there have been certainly done 376 00:21:56,840 --> 00:22:02,600 Speaker 1: some some very asymmetrical looking airplane designs uh uh here 377 00:22:02,600 --> 00:22:05,920 Speaker 1: and there throughout aviation history, they do look incredibly wrong 378 00:22:05,960 --> 00:22:09,439 Speaker 1: to the eye. Um, and that shouldn't fly. Yeah, Like 379 00:22:09,480 --> 00:22:11,720 Speaker 1: how how how is that a good idea? But I 380 00:22:11,720 --> 00:22:15,720 Speaker 1: mean it can work, it's just you you generally don't 381 00:22:15,760 --> 00:22:18,240 Speaker 1: see it. Well, there's a different logic at work here. 382 00:22:18,280 --> 00:22:21,200 Speaker 1: But that just sort of reminds me, incidentally of how 383 00:22:21,240 --> 00:22:23,560 Speaker 1: I'm always surprised at the idea that a plane can 384 00:22:23,600 --> 00:22:25,960 Speaker 1: continue to fly with one engine, you know, as like 385 00:22:26,040 --> 00:22:28,600 Speaker 1: two jet engines, Like one engine fails, but it can 386 00:22:28,680 --> 00:22:31,000 Speaker 1: keep flying with the other one, which makes that that 387 00:22:31,040 --> 00:22:33,240 Speaker 1: doesn't seem right. It seems like, well, if only one 388 00:22:33,320 --> 00:22:35,320 Speaker 1: engine is going, then shouldn't it just sort of like 389 00:22:35,400 --> 00:22:38,320 Speaker 1: spin out of control? But no, I mean, as long 390 00:22:38,359 --> 00:22:42,120 Speaker 1: as it's generating forward thrust, it can keep going usually Yeah. 391 00:22:42,880 --> 00:22:45,679 Speaker 1: But anyway, so there's always a strong argument, you know, 392 00:22:45,720 --> 00:22:49,399 Speaker 1: that much of what we find beautiful and good is 393 00:22:49,680 --> 00:22:53,320 Speaker 1: biologically contingent, that it has at least in part to 394 00:22:53,440 --> 00:22:55,760 Speaker 1: do with the kind of animals we are and how 395 00:22:55,800 --> 00:22:58,600 Speaker 1: we relate to our environment. And of course we are 396 00:22:58,680 --> 00:23:01,520 Speaker 1: part of that clade of animal all is known as biolateria. 397 00:23:01,760 --> 00:23:07,719 Speaker 1: These these are the animals featuring bilateral symmetry during embryonic development. Now, 398 00:23:07,720 --> 00:23:10,240 Speaker 1: of course this is always approximate, right, because while you're 399 00:23:10,320 --> 00:23:12,879 Speaker 1: left and you're right in one sense do match. There 400 00:23:12,880 --> 00:23:14,960 Speaker 1: are mirror images of each other, as you were just 401 00:23:15,000 --> 00:23:18,359 Speaker 1: talking about, they're not perfect mirror images of each other, 402 00:23:18,400 --> 00:23:21,880 Speaker 1: and especially on the inside, because we have say, asymmetric 403 00:23:21,960 --> 00:23:24,679 Speaker 1: distribution of our internal organs, like the hearts more to 404 00:23:24,720 --> 00:23:27,000 Speaker 1: one side, the livers more to the other, and so forth. 405 00:23:27,040 --> 00:23:31,280 Speaker 1: But for it, for approximate terms, at least externally are 406 00:23:31,400 --> 00:23:33,920 Speaker 1: left in our right sides match. But not all animals 407 00:23:33,920 --> 00:23:38,040 Speaker 1: exhibit bilateral symmetry. Some have radial symmetry, meaning they grow 408 00:23:38,080 --> 00:23:41,800 Speaker 1: in like repeated structures in a more spiral pattern. And 409 00:23:41,840 --> 00:23:44,720 Speaker 1: there are some like sponges for example, those are animals, 410 00:23:44,720 --> 00:23:47,600 Speaker 1: but they have no symmetry at all. But most animals, 411 00:23:47,600 --> 00:23:51,600 Speaker 1: like humans, are bilaterally symmetrical. As as our bodies grow 412 00:23:51,680 --> 00:23:56,600 Speaker 1: during embryonic development, they grow into basically mirrored halves on 413 00:23:56,640 --> 00:23:59,399 Speaker 1: the left and right. But as we've already seen with 414 00:23:59,400 --> 00:24:03,600 Speaker 1: the narwhale, some animals with bodies that mostly adhere to 415 00:24:03,760 --> 00:24:10,240 Speaker 1: bilateral symmetry present with isolated but radical deviations, such as 416 00:24:10,359 --> 00:24:14,439 Speaker 1: the nar walls left maxillary canine turning into a tusk 417 00:24:14,560 --> 00:24:17,840 Speaker 1: almost as long as the animal itself. And this is 418 00:24:17,920 --> 00:24:21,879 Speaker 1: not even the only example of fascinating a symmetry in 419 00:24:21,920 --> 00:24:25,440 Speaker 1: the bodies of whales. Yeah, yeah, I want to get 420 00:24:25,480 --> 00:24:28,320 Speaker 1: into something that we may have touched on this a 421 00:24:28,359 --> 00:24:31,879 Speaker 1: little bit in the past, But despite the number of 422 00:24:31,880 --> 00:24:34,560 Speaker 1: times the whales come up, I don't think we've really 423 00:24:34,960 --> 00:24:37,600 Speaker 1: gotten into everything here. And it concerns the nature of 424 00:24:37,640 --> 00:24:42,800 Speaker 1: the blowhole of of whales. Um Again, it just drives 425 00:24:42,800 --> 00:24:47,719 Speaker 1: home just how mysterious and weird whales really are. Um 426 00:24:47,760 --> 00:24:50,200 Speaker 1: So I want to start sort of back up before 427 00:24:50,200 --> 00:24:53,480 Speaker 1: we get to where we're going with this discussion of blowholes, 428 00:24:53,480 --> 00:24:55,840 Speaker 1: and start with the baileeen whale. You know, these are 429 00:24:55,880 --> 00:25:00,560 Speaker 1: filter feeders, which, as Ryan Tucker Jones points out in 430 00:25:00,600 --> 00:25:04,400 Speaker 1: red Leviathan uh the book about Soviet whaling, and interviewed 431 00:25:04,520 --> 00:25:08,800 Speaker 1: uh Ryan last week on the show. It's really fun episode. 432 00:25:08,800 --> 00:25:10,560 Speaker 1: If anyone wants to go back and listen to that. 433 00:25:10,880 --> 00:25:15,600 Speaker 1: But there's he touches on just sort of how intertwined 434 00:25:15,760 --> 00:25:19,359 Speaker 1: folk tale and legend and mythology is with our understanding 435 00:25:19,480 --> 00:25:22,640 Speaker 1: of whales and misunderstanding of whales. I want to read 436 00:25:22,640 --> 00:25:26,680 Speaker 1: this one passage quote. Ancient Greeks knew far less about 437 00:25:26,680 --> 00:25:30,359 Speaker 1: whales than did the whaling Scandinavians. And as these word 438 00:25:30,400 --> 00:25:34,520 Speaker 1: origins suggests, whales remain mysterious for Russians. For one thing, 439 00:25:34,600 --> 00:25:38,560 Speaker 1: baleen whales methods of feeding perplexed them. Lacking teeth, the 440 00:25:38,640 --> 00:25:41,560 Speaker 1: giants seemed to have no way of capturing prey. One 441 00:25:41,600 --> 00:25:45,399 Speaker 1: tenth century Russian poem wondered whether wales quote the mother 442 00:25:45,760 --> 00:25:50,400 Speaker 1: of all fish unquote fed themselves on quote heavenly fragrances. 443 00:25:51,080 --> 00:25:55,360 Speaker 1: Direct experience was not necessarily more helpful. A medieval Western 444 00:25:55,359 --> 00:25:58,280 Speaker 1: whaler who cut into a stranded whale stomach and found 445 00:25:58,280 --> 00:26:01,600 Speaker 1: a gray mass of food included that it had fed 446 00:26:01,720 --> 00:26:09,920 Speaker 1: on quote internal fog. That's great. So yes, whales are mysterious, 447 00:26:10,200 --> 00:26:12,360 Speaker 1: and yeah, you can you can imagine if you really 448 00:26:12,359 --> 00:26:14,440 Speaker 1: didn't know what was going on with the baleen whale, 449 00:26:14,800 --> 00:26:18,399 Speaker 1: you might have trouble figuring out what's going on with 450 00:26:18,560 --> 00:26:22,679 Speaker 1: their with with their mouths. What do they truly feed on? What? 451 00:26:22,680 --> 00:26:24,840 Speaker 1: What is there enough of on the ocean for them 452 00:26:24,840 --> 00:26:28,960 Speaker 1: to consume if they're not eating our ships and so forth. 453 00:26:29,800 --> 00:26:32,080 Speaker 1: So anyway, if you look at a baleen whale and 454 00:26:32,640 --> 00:26:35,840 Speaker 1: you look away from its mouth, you'll notice, yes, it 455 00:26:35,920 --> 00:26:39,720 Speaker 1: has it has the blowholes. The blowhole falls well in 456 00:26:40,080 --> 00:26:43,480 Speaker 1: line with bilateral anatomy. There are two of them, in 457 00:26:43,560 --> 00:26:46,400 Speaker 1: kind of a V shape. And uh, and guess what 458 00:26:46,480 --> 00:26:49,000 Speaker 1: if you weren't aware of this, here's your your fun Uh. 459 00:26:49,359 --> 00:26:55,040 Speaker 1: Initial fact, they are repositioned nostrils. Imagining the evolutionary journey 460 00:26:55,240 --> 00:26:58,879 Speaker 1: of those nose holes. Yes, because that's it is a journey, 461 00:26:58,920 --> 00:27:01,800 Speaker 1: the nose holes traveling from the front of the snout 462 00:27:02,320 --> 00:27:03,919 Speaker 1: all the way to the top of the head. I mean, 463 00:27:04,000 --> 00:27:06,040 Speaker 1: we can imagine it. It's hard to imagine with our 464 00:27:06,080 --> 00:27:08,760 Speaker 1: own face, but imagine it with a much bigger and 465 00:27:08,920 --> 00:27:13,800 Speaker 1: more prolonged heading. So, as Raston and Roth point out 466 00:27:13,840 --> 00:27:17,399 Speaker 1: in a paper published in the Journal of Anatomy, uh, 467 00:27:17,440 --> 00:27:22,679 Speaker 1: the nasal passage in in these whales has rotated dorsally 468 00:27:22,840 --> 00:27:27,320 Speaker 1: over the course of evolution and early in development cessation 469 00:27:27,440 --> 00:27:31,800 Speaker 1: embryos have head morphologies that resemble other mammals, so you 470 00:27:31,800 --> 00:27:36,360 Speaker 1: can actually look up embryo images and observe the nasal 471 00:27:36,560 --> 00:27:40,119 Speaker 1: openings shift from the tip of the snout to the 472 00:27:40,160 --> 00:27:43,040 Speaker 1: back of the head. If you want to see some 473 00:27:43,040 --> 00:27:46,800 Speaker 1: some some easily accessed examples of this panda's thumb. A 474 00:27:46,880 --> 00:27:49,840 Speaker 1: science blog has some great images of this in their 475 00:27:49,880 --> 00:27:53,600 Speaker 1: post whale evolution The Blowhole, and I included these for 476 00:27:53,640 --> 00:27:56,520 Speaker 1: you to look at here, Joe Um. If you if 477 00:27:56,520 --> 00:27:58,679 Speaker 1: you look up this blog post, you'll see a trio 478 00:27:58,720 --> 00:28:01,720 Speaker 1: of images with the embryo and there's a little white 479 00:28:01,800 --> 00:28:05,760 Speaker 1: ero pointing out where the nostrils are and then where 480 00:28:05,800 --> 00:28:08,640 Speaker 1: they travel to. It's just as you say, yeah, so 481 00:28:09,040 --> 00:28:11,760 Speaker 1: earlier in development there there towards the front like they 482 00:28:11,800 --> 00:28:13,720 Speaker 1: would be on the snout, and more like they would 483 00:28:13,720 --> 00:28:18,040 Speaker 1: have been on the whales, on the whales land walking ancestors. 484 00:28:18,040 --> 00:28:20,560 Speaker 1: But yeah, then as development moves on, they move up 485 00:28:20,640 --> 00:28:23,240 Speaker 1: the head up to where I don't know, I don't 486 00:28:23,240 --> 00:28:24,800 Speaker 1: know if this is the right terminology, but you might 487 00:28:24,800 --> 00:28:28,879 Speaker 1: call like the forehead and then further and further. Yeah. Yeah, 488 00:28:29,000 --> 00:28:33,840 Speaker 1: now it's it's obviously natural selection went this way. Um 489 00:28:33,960 --> 00:28:37,159 Speaker 1: and it's easy to just sort of assume, okay, natural 490 00:28:37,600 --> 00:28:40,640 Speaker 1: um evolution and natural selection and knows what it's doing. 491 00:28:41,160 --> 00:28:42,960 Speaker 1: Who are we to question it? So it's easy to 492 00:28:43,000 --> 00:28:45,000 Speaker 1: sort of overlook the basic question and all of this, 493 00:28:45,440 --> 00:28:48,880 Speaker 1: why why does the nostril why did the nose open on? 494 00:28:49,080 --> 00:28:52,000 Speaker 1: The nasal openings on these creatures wander over the course 495 00:28:52,000 --> 00:28:54,920 Speaker 1: of their evolutionary development until they're on the top of 496 00:28:54,960 --> 00:28:58,600 Speaker 1: the head. The basic answer is that while these creatures, yes, 497 00:28:58,640 --> 00:29:01,880 Speaker 1: technically could still ether through their nostrils when they were 498 00:29:01,880 --> 00:29:04,200 Speaker 1: positioned at the end of their snouts, they would have 499 00:29:04,240 --> 00:29:06,880 Speaker 1: to lift their snouts out of the water to do so, 500 00:29:07,560 --> 00:29:10,600 Speaker 1: and that requires more energy. If it's if you have 501 00:29:10,680 --> 00:29:13,840 Speaker 1: the nose and the nasal openings positioned higher up on 502 00:29:13,880 --> 00:29:17,160 Speaker 1: the snout, well, that's less lift required to do so, 503 00:29:17,320 --> 00:29:20,400 Speaker 1: less energy, And so this is why we have that 504 00:29:20,520 --> 00:29:24,600 Speaker 1: gradual movement of the nasal openings. And we have fossil 505 00:29:24,720 --> 00:29:27,200 Speaker 1: evidence to back this up, and there are examples of 506 00:29:27,240 --> 00:29:30,320 Speaker 1: this in that panda's thumb post as well. We for instance, 507 00:29:30,360 --> 00:29:34,040 Speaker 1: we have fossil evidence of of Rhodo satus. This is 508 00:29:34,080 --> 00:29:38,800 Speaker 1: a whale from roughly forty six million years ago, and 509 00:29:38,880 --> 00:29:43,640 Speaker 1: this one offers a midpoint where we see the nasal opening, 510 00:29:43,880 --> 00:29:45,560 Speaker 1: not at the end of the snout like we see 511 00:29:45,600 --> 00:29:50,280 Speaker 1: in uh in really ancient UH whale ancestors, and also 512 00:29:50,360 --> 00:29:51,680 Speaker 1: not at the top of the head like we see 513 00:29:51,680 --> 00:29:55,280 Speaker 1: with modern whales, but that midpoint in between. No, I'm 514 00:29:55,320 --> 00:29:58,800 Speaker 1: not speaking from an expert perspective here, but it seems 515 00:29:59,600 --> 00:30:03,520 Speaker 1: very sgnificant that the that the blowhole eventually moves back 516 00:30:03,560 --> 00:30:06,320 Speaker 1: to above where the eyes are right because you can 517 00:30:06,360 --> 00:30:10,280 Speaker 1: imagine if a whale has to lift its eyes above 518 00:30:10,440 --> 00:30:13,120 Speaker 1: the surface of the water every time it wants to breathe, 519 00:30:13,240 --> 00:30:15,520 Speaker 1: or at least to point its eyes up away from 520 00:30:15,520 --> 00:30:19,719 Speaker 1: where it's scanning. That's really it's not just taking energy. 521 00:30:19,760 --> 00:30:23,160 Speaker 1: I mean, of course, the energetic investment is significant. Imagine 522 00:30:23,160 --> 00:30:25,520 Speaker 1: if you had to like lift your head up every 523 00:30:25,520 --> 00:30:27,640 Speaker 1: time you wanted to breathe, that would that would get 524 00:30:27,640 --> 00:30:30,480 Speaker 1: tiring after a while. But also if you basically like 525 00:30:30,520 --> 00:30:32,880 Speaker 1: couldn't see what was going on around you every time 526 00:30:32,920 --> 00:30:34,920 Speaker 1: you had to take a breath, because you know, you 527 00:30:34,960 --> 00:30:37,280 Speaker 1: need if you're living under the water, you want to 528 00:30:37,360 --> 00:30:39,960 Speaker 1: keep your eyes fixed below the water, that's where the 529 00:30:40,000 --> 00:30:42,240 Speaker 1: relevant stuff is going on. If you have to lift 530 00:30:42,280 --> 00:30:45,120 Speaker 1: your eyes above the surface of the water. Uh you 531 00:30:45,160 --> 00:30:48,440 Speaker 1: are you are losing sight of your surroundings exactly. Yeah, 532 00:30:48,840 --> 00:30:52,120 Speaker 1: this is the world that the whale has adapted to 533 00:30:52,640 --> 00:30:56,440 Speaker 1: the marine environment, and so over time it just gets 534 00:30:56,480 --> 00:30:59,080 Speaker 1: to the point where as little of the animal as 535 00:30:59,120 --> 00:31:06,320 Speaker 1: possible has to breach the surface of the water. Thank 536 00:31:08,240 --> 00:31:12,560 Speaker 1: So that's basically the symmetrical whale blow hole. But here's 537 00:31:12,600 --> 00:31:13,960 Speaker 1: the here's where it gets fun. This is where it 538 00:31:13,960 --> 00:31:18,360 Speaker 1: gets asymmetrical because not all whales have two blow holes. 539 00:31:19,000 --> 00:31:22,880 Speaker 1: Not all have those two nasal openings repurpose nasal openings 540 00:31:22,920 --> 00:31:25,840 Speaker 1: on the top of their head. Toothed whales like the 541 00:31:25,840 --> 00:31:31,240 Speaker 1: sperm whale, have just one. In fact, on the sperm whale, 542 00:31:31,560 --> 00:31:35,000 Speaker 1: this single blowhole is at an angle on the left 543 00:31:35,000 --> 00:31:37,200 Speaker 1: side of the head, and this causes it to blow 544 00:31:37,640 --> 00:31:41,480 Speaker 1: forward and slightly to the left. So this can actually 545 00:31:41,520 --> 00:31:45,600 Speaker 1: make sperm whale spouts harder to spot for humans, but 546 00:31:45,720 --> 00:31:49,040 Speaker 1: also makes them easier to identify if you do spot them, 547 00:31:49,080 --> 00:31:53,360 Speaker 1: because it's not just blasting straight up again, it's blasting 548 00:31:53,680 --> 00:31:56,600 Speaker 1: forward and slightly to the left. But this, oh, this 549 00:31:56,680 --> 00:31:58,920 Speaker 1: is this is putting me back in our wall tusk territory. 550 00:31:59,000 --> 00:32:02,959 Speaker 1: So it has one nostril. So this is not just 551 00:32:03,040 --> 00:32:06,360 Speaker 1: the nostrils have moved back along the center line of 552 00:32:06,400 --> 00:32:10,440 Speaker 1: the skull of cross evolutionary time. The nostrils have actually 553 00:32:10,520 --> 00:32:14,120 Speaker 1: split and one of them has moved back here and 554 00:32:14,160 --> 00:32:17,760 Speaker 1: the other one, I don't know what it's doing something else, Yeah, 555 00:32:17,840 --> 00:32:21,480 Speaker 1: the other one. The crazy thing is essentially the one 556 00:32:21,520 --> 00:32:23,960 Speaker 1: is still open and active. The other one has sealed 557 00:32:24,000 --> 00:32:26,560 Speaker 1: over the other. So the other nasal passage is there. 558 00:32:26,960 --> 00:32:30,360 Speaker 1: It just does not connect to the surface anymore. Uh. 559 00:32:30,480 --> 00:32:33,440 Speaker 1: That doesn't mean it's not doing anything. It has another purpose. 560 00:32:34,280 --> 00:32:37,840 Speaker 1: So instead of connecting to the exterior of the animal, 561 00:32:38,160 --> 00:32:42,000 Speaker 1: this other nasal passage supplies air to the phonic lips. 562 00:32:42,440 --> 00:32:45,520 Speaker 1: The phonic lips produce clicks that travel the length of 563 00:32:45,560 --> 00:32:49,800 Speaker 1: the nose and through the spermssete oregon of the head 564 00:32:50,320 --> 00:32:52,560 Speaker 1: UH to aid in echolocation, or at least this is 565 00:32:52,560 --> 00:32:55,400 Speaker 1: the most well accepted theory of what's going on here 566 00:32:55,480 --> 00:32:58,959 Speaker 1: with the structure of the sperm whale's head. So echolocation 567 00:32:59,600 --> 00:33:02,520 Speaker 1: is using sound waves in order to be able to 568 00:33:02,800 --> 00:33:06,480 Speaker 1: UH image underwater to see where things are not with vision, 569 00:33:06,840 --> 00:33:09,600 Speaker 1: but by producing clicks that like hit things in the 570 00:33:09,600 --> 00:33:13,000 Speaker 1: water and then come back to the sensory organs on 571 00:33:13,040 --> 00:33:16,520 Speaker 1: the whale so they can navigate their environment. And as specifically, 572 00:33:16,560 --> 00:33:19,560 Speaker 1: I think nowhere prey is in the dark waters. Yeah, 573 00:33:19,640 --> 00:33:22,320 Speaker 1: so if you dive in down to eat yourself some 574 00:33:22,320 --> 00:33:25,640 Speaker 1: some squids, some giant squid maybe, uh, this is what 575 00:33:25,720 --> 00:33:29,280 Speaker 1: you would you would use. Now. The evolutionary divergence likely 576 00:33:29,320 --> 00:33:31,920 Speaker 1: occurred during the oligo scene. This would have been thirty 577 00:33:31,920 --> 00:33:34,920 Speaker 1: three to twenty three million years ago, as toothed whales 578 00:33:34,960 --> 00:33:39,640 Speaker 1: diverged from the ancestors of filter feeding whales, and this 579 00:33:39,680 --> 00:33:44,280 Speaker 1: would totally make sense of predatory Toothed whales develop asymmetry 580 00:33:44,360 --> 00:33:48,280 Speaker 1: related to their ability to echo locate because they need 581 00:33:48,320 --> 00:33:51,600 Speaker 1: to use echolocation to hunt. Filter feeding whales do not 582 00:33:51,760 --> 00:33:54,720 Speaker 1: have the same hunting needs, so their skulls remain balanced 583 00:33:54,760 --> 00:33:58,240 Speaker 1: on the left and right. Um and uh rob I 584 00:33:58,320 --> 00:34:00,360 Speaker 1: I thought this was a really interesting end and so 585 00:34:00,400 --> 00:34:02,400 Speaker 1: I was looking at to support this. I found a 586 00:34:03,080 --> 00:34:06,320 Speaker 1: paper on the cranial asymmetry of whales and this was 587 00:34:06,440 --> 00:34:10,719 Speaker 1: by Ellen J. Coombs at all published in BMC Biology 588 00:34:10,760 --> 00:34:16,799 Speaker 1: in and for this paper, making use of museum collections, 589 00:34:16,840 --> 00:34:20,920 Speaker 1: the researchers compared whale skulls across time, reaching back to 590 00:34:21,400 --> 00:34:25,200 Speaker 1: whale ancestors that lived fifty million years ago, and the 591 00:34:25,239 --> 00:34:29,000 Speaker 1: author's write quote early ancestors of living whales had little 592 00:34:29,080 --> 00:34:32,840 Speaker 1: cranial asymmetry and likely we're not able to echo locate 593 00:34:33,200 --> 00:34:37,320 Speaker 1: our cho seats display high levels of asymmetry in the rostrum, 594 00:34:37,360 --> 00:34:40,840 Speaker 1: potentially related to directional hearing, which is lost in early 595 00:34:40,920 --> 00:34:44,240 Speaker 1: neo seats. The tax on, including the most recent common 596 00:34:44,280 --> 00:34:50,440 Speaker 1: ancestor of living cetaceans naso facial asymmetry. So again, asymmetrical 597 00:34:51,440 --> 00:34:55,080 Speaker 1: placement of the nostrils in the face becomes a significant 598 00:34:55,160 --> 00:34:58,440 Speaker 1: feature of odonto cetti or toothed whales in the early 599 00:34:58,520 --> 00:35:01,760 Speaker 1: oligo scene, just like you said, um reaching its highest 600 00:35:01,840 --> 00:35:06,400 Speaker 1: levels in extant taxa. Separate evolutionary regimes are reconstructed for 601 00:35:06,440 --> 00:35:11,800 Speaker 1: odonta seats living in acoustically complex environments, suggesting that these 602 00:35:11,880 --> 00:35:16,360 Speaker 1: niches impose strong selective pressure on echolocation ability and thus 603 00:35:16,600 --> 00:35:23,440 Speaker 1: increased cranial asymmetry. So, to summarize the skulls of toothed whales, specifically, 604 00:35:23,480 --> 00:35:28,080 Speaker 1: the toothed ones just keep getting weirder and more asymmetrical 605 00:35:28,320 --> 00:35:32,360 Speaker 1: over evolutionary time. Uh So, as the millions of years 606 00:35:32,400 --> 00:35:35,839 Speaker 1: march on, the heads are getting less and less symmetrical, 607 00:35:36,360 --> 00:35:40,160 Speaker 1: and this is especially true apparently in places where echolocation 608 00:35:40,280 --> 00:35:44,279 Speaker 1: is more difficult due to environmental conditions. And what could 609 00:35:44,280 --> 00:35:47,400 Speaker 1: be an example of this, Well, I was looking in 610 00:35:47,440 --> 00:35:49,960 Speaker 1: the paper and this could be a coincidence, but they 611 00:35:50,000 --> 00:35:54,960 Speaker 1: note that the nar wall has an unusually asymmetrical skull 612 00:35:55,120 --> 00:35:58,200 Speaker 1: apart from the tusk that juts out on one side. 613 00:35:58,840 --> 00:36:00,680 Speaker 1: So to read a quote from this paper with a 614 00:36:00,760 --> 00:36:04,239 Speaker 1: bit of paraphrasing, uh, and remember the genus of the 615 00:36:04,320 --> 00:36:10,120 Speaker 1: narwhall is Monodon one tooth, meaning Monodon monodon remains the 616 00:36:10,120 --> 00:36:14,279 Speaker 1: most asymmetric skull in the sample, even when the rostrum 617 00:36:14,320 --> 00:36:18,200 Speaker 1: is removed, which rules out the possibility that an asymmetric 618 00:36:18,320 --> 00:36:22,040 Speaker 1: tusk and residual teeth may be skewing the overall result. 619 00:36:22,800 --> 00:36:27,440 Speaker 1: Their unique sound repertoire narrow band structured in BS is 620 00:36:27,480 --> 00:36:32,080 Speaker 1: ideal for projecting and receiving signals in icy shallow waters 621 00:36:32,360 --> 00:36:35,520 Speaker 1: where the animals can detect targets in high levels of 622 00:36:35,600 --> 00:36:40,319 Speaker 1: ambient noise and back scatter. So that's interesting. This could 623 00:36:40,320 --> 00:36:42,720 Speaker 1: be a total coincidence. I would not want to suggest 624 00:36:42,760 --> 00:36:46,359 Speaker 1: a causal connection, but I don't know. It's stuck out 625 00:36:46,400 --> 00:36:51,520 Speaker 1: to me that nar walls have both strongly asymmetrical skulls, 626 00:36:51,560 --> 00:36:56,680 Speaker 1: probably to aid in echolocation in a difficult environment, and 627 00:36:56,880 --> 00:37:02,480 Speaker 1: also extreme asymmetrical teeth, producing these tusks, probably as a 628 00:37:02,520 --> 00:37:06,200 Speaker 1: sexually selected trade. Yeah. I mean again, it just goes 629 00:37:06,640 --> 00:37:09,640 Speaker 1: to show you just how weird whales are. Like, they're 630 00:37:09,680 --> 00:37:13,919 Speaker 1: just so delightfully strange. Um and and again it's easy 631 00:37:13,960 --> 00:37:15,800 Speaker 1: to it's easy to take it for granted if you don't, 632 00:37:16,520 --> 00:37:19,080 Speaker 1: you don't lean in closely enough, you know. But as 633 00:37:19,080 --> 00:37:21,960 Speaker 1: wonderful as as whale bodies are, they are not the 634 00:37:22,000 --> 00:37:27,240 Speaker 1: only creatures in the sea with striking and fascinating imbalances 635 00:37:27,320 --> 00:37:30,600 Speaker 1: between their left and right sides. Yeah, they're There are 636 00:37:30,600 --> 00:37:33,880 Speaker 1: a number of fascinating examples we could turn to, and 637 00:37:33,880 --> 00:37:35,120 Speaker 1: I don't know, we may we may come back to 638 00:37:35,160 --> 00:37:38,720 Speaker 1: some more in future episodes. But one that really caught 639 00:37:38,760 --> 00:37:44,480 Speaker 1: my attention is histeo tooth, the cock eyed squid. So 640 00:37:44,600 --> 00:37:49,520 Speaker 1: this is another example of essentially divided attention and divided 641 00:37:49,600 --> 00:37:55,799 Speaker 1: bodies in the deep ocean. Uh So, histeotoothis resides and 642 00:37:56,080 --> 00:37:59,680 Speaker 1: the mesopelagic zone or the twilight zone of the ocean. 643 00:38:00,320 --> 00:38:02,480 Speaker 1: And you can certainly think of this as a realm 644 00:38:02,719 --> 00:38:09,160 Speaker 1: situated between different kingdoms of illumination because above the zone 645 00:38:09,719 --> 00:38:12,719 Speaker 1: above the creatures of this realm, well, there there's the 646 00:38:12,880 --> 00:38:17,240 Speaker 1: that there's the distant kingdom of light. Okay. Uh, there's 647 00:38:17,239 --> 00:38:20,680 Speaker 1: a dim illumination coming down from the sun from the 648 00:38:21,400 --> 00:38:25,040 Speaker 1: more sunlit portions of the ocean, and so silhouettes can 649 00:38:25,080 --> 00:38:29,200 Speaker 1: be viewed of creatures above you against that that faint 650 00:38:29,280 --> 00:38:33,239 Speaker 1: light below you. Well, there's the great darkness of the 651 00:38:33,400 --> 00:38:36,719 Speaker 1: of the depths. But in that great dark darkness you'll 652 00:38:36,800 --> 00:38:39,680 Speaker 1: glimpse or if you're a squid to mule, glimpse uh, 653 00:38:39,719 --> 00:38:44,239 Speaker 1: sparkles and pulsations of bioluminescence here and there. Uh. And 654 00:38:44,520 --> 00:38:48,120 Speaker 1: of course both of these sightings are important because they 655 00:38:48,160 --> 00:38:50,960 Speaker 1: both have to do with organisms that may be a 656 00:38:51,000 --> 00:38:54,200 Speaker 1: threat that maybe food, et cetera. Oh, well, this is 657 00:38:54,239 --> 00:38:57,080 Speaker 1: so interesting because we know of lots of examples on 658 00:38:57,120 --> 00:38:59,800 Speaker 1: the surface world, say like lots of herbivores on the 659 00:39:00,120 --> 00:39:02,160 Speaker 1: this world that have one eye on each side of 660 00:39:02,200 --> 00:39:04,719 Speaker 1: their head to try to provide a sort of you know, 661 00:39:04,760 --> 00:39:07,279 Speaker 1: as wide field of you as possible, so you can 662 00:39:07,280 --> 00:39:10,799 Speaker 1: see things approaching you. But this is a scenario where 663 00:39:10,880 --> 00:39:13,560 Speaker 1: you might have a head structured like that, but you 664 00:39:13,600 --> 00:39:18,000 Speaker 1: have totally different seeing needs on either side exactly. And 665 00:39:18,040 --> 00:39:20,560 Speaker 1: so that's that's what we see with his teo toothis 666 00:39:20,719 --> 00:39:24,600 Speaker 1: as as described by Thomas, Robinson and Johnson in their 667 00:39:25,480 --> 00:39:28,920 Speaker 1: paper in the Philosophical Transactions of the Royal Society B 668 00:39:29,560 --> 00:39:33,120 Speaker 1: it is a creature with quote two eyes for two purposes. 669 00:39:33,640 --> 00:39:37,360 Speaker 1: So the squids two eyes here are dimorphic in size, 670 00:39:37,360 --> 00:39:41,759 Speaker 1: shape and sometimes lens pigmentation. I included an image for 671 00:39:41,800 --> 00:39:44,920 Speaker 1: you to look at here, Joe, and you can folks listening, 672 00:39:45,480 --> 00:39:48,200 Speaker 1: and you can look up images this as well. Um, 673 00:39:48,360 --> 00:39:50,160 Speaker 1: not all images of the squid are going to really 674 00:39:50,200 --> 00:39:52,839 Speaker 1: capture this, but you'll find some that do. And it's 675 00:39:52,960 --> 00:39:56,200 Speaker 1: it's very weird when you can see both eyes at 676 00:39:56,239 --> 00:39:59,200 Speaker 1: once because one, uh, the image I was looking at. 677 00:39:59,440 --> 00:40:02,600 Speaker 1: One eye is this great, big, kind of swollen looking 678 00:40:02,680 --> 00:40:05,520 Speaker 1: eye that has kind of a yellowish or greenish tint 679 00:40:05,560 --> 00:40:08,480 Speaker 1: to it. Um it may appear to be glowing the 680 00:40:08,520 --> 00:40:11,000 Speaker 1: way that the light is catching it, and the other 681 00:40:11,080 --> 00:40:16,080 Speaker 1: eye appears a smaller, flatter um. You know, almost looks 682 00:40:16,120 --> 00:40:18,200 Speaker 1: like if you didn't know what you're looking at, you 683 00:40:18,280 --> 00:40:20,720 Speaker 1: might think, oh, this poor squid, one of its eyes 684 00:40:20,800 --> 00:40:23,879 Speaker 1: is inflamed and swollen, or one of its eyes has 685 00:40:23,920 --> 00:40:27,640 Speaker 1: been severely wounded and doesn't look like it's it's operating anymore. 686 00:40:27,680 --> 00:40:31,440 Speaker 1: But no, both eyes are operating. They're just pointed in 687 00:40:31,520 --> 00:40:35,880 Speaker 1: different directions, and they have evolved to see differently depending 688 00:40:35,960 --> 00:40:40,280 Speaker 1: on uh the environments that they're gazing into. It's beautiful, 689 00:40:40,400 --> 00:40:45,080 Speaker 1: one looks like a setting gangrenous sun, and the other 690 00:40:45,239 --> 00:40:48,640 Speaker 1: looks like a blueberry that's a little bit rotten. Right, 691 00:40:49,680 --> 00:40:52,280 Speaker 1: So it's thought that the larger of the two eyes 692 00:40:52,680 --> 00:40:56,760 Speaker 1: is honed to spot objects silhouetted against that dim light above, 693 00:40:57,320 --> 00:41:00,880 Speaker 1: while the smaller eye specializes in spot the sources of 694 00:41:00,920 --> 00:41:05,160 Speaker 1: bioluminescence in the darkness below, and the squid will actually 695 00:41:05,200 --> 00:41:08,560 Speaker 1: position itself in a tail up position in order to 696 00:41:08,680 --> 00:41:13,640 Speaker 1: maximize the split vision. Furthermore, the authors share that that 697 00:41:13,680 --> 00:41:16,360 Speaker 1: the there that we do seem to have yellow pigments 698 00:41:16,440 --> 00:41:19,799 Speaker 1: in the larger eye that may serve to break the 699 00:41:19,960 --> 00:41:25,160 Speaker 1: counter illumination camouflage of their prey above. Counter illumination is 700 00:41:25,200 --> 00:41:29,880 Speaker 1: an active camouflage method by by which lights are produced 701 00:41:29,880 --> 00:41:32,640 Speaker 1: on the body to match background lights. So this would 702 00:41:32,680 --> 00:41:34,560 Speaker 1: be used by a creature to blend in with the 703 00:41:34,680 --> 00:41:38,879 Speaker 1: light above it, so the creatures below them don't so 704 00:41:38,960 --> 00:41:43,160 Speaker 1: cleanly make out their dark bodies against the dim lights above. Oh, 705 00:41:43,200 --> 00:41:46,239 Speaker 1: that's a good survival strategy. Yeah, you have lights on 706 00:41:46,280 --> 00:41:49,719 Speaker 1: your underside to mimic the sunlight. Yeah. And so that 707 00:41:49,800 --> 00:41:52,640 Speaker 1: the yellow pigments in this larger eye apparently helps to 708 00:41:52,680 --> 00:41:56,040 Speaker 1: sort of break through some of that. So the theory 709 00:41:56,120 --> 00:42:00,239 Speaker 1: is that we see dimorphic specializations in each eye as 710 00:42:00,239 --> 00:42:05,120 Speaker 1: an adaptation to the split visual world. And this actually 711 00:42:05,120 --> 00:42:09,560 Speaker 1: reminded me of of a bit from a Doctor Seuss book. 712 00:42:09,680 --> 00:42:12,279 Speaker 1: I had trouble in getting to Solo Salu, where you 713 00:42:12,320 --> 00:42:14,560 Speaker 1: have this character who's dealing with a bunch of threats 714 00:42:14,880 --> 00:42:17,359 Speaker 1: and it goes So I said to myself, now, I'll 715 00:42:17,400 --> 00:42:19,640 Speaker 1: just have to start to be twice as careful and 716 00:42:19,680 --> 00:42:22,440 Speaker 1: be twice as smart. I'll watch out for trouble in 717 00:42:22,520 --> 00:42:26,040 Speaker 1: front and back sections by aiming my eyeballs in different directions. 718 00:42:26,440 --> 00:42:28,440 Speaker 1: And you have this character that's kind of like a 719 00:42:28,440 --> 00:42:31,400 Speaker 1: little bear creature in his eyes are gazing off in 720 00:42:31,440 --> 00:42:34,239 Speaker 1: different directions. But essentially like that's that's kind of what 721 00:42:34,440 --> 00:42:36,520 Speaker 1: is going on with the with the cock eyed squid here. 722 00:42:36,760 --> 00:42:39,720 Speaker 1: That's great. It is, so I was trying to imagine 723 00:42:39,760 --> 00:42:43,640 Speaker 1: what scenario could give rise to something like this on 724 00:42:43,719 --> 00:42:46,640 Speaker 1: a on a land dwelling herbivore. You know, so you 725 00:42:46,680 --> 00:42:49,359 Speaker 1: have like a bo vine that's grazing what it needs 726 00:42:49,400 --> 00:42:52,080 Speaker 1: have totally different types of eyes or vision on one 727 00:42:52,120 --> 00:42:53,960 Speaker 1: side of the head. And I imagine what about some 728 00:42:54,040 --> 00:42:57,160 Speaker 1: kind of bovine that lives on a tidally locked world, 729 00:42:57,239 --> 00:43:00,560 Speaker 1: and it it lives at the terminator line. So it's 730 00:43:00,640 --> 00:43:03,759 Speaker 1: I one eye needs to be like shielded because it's 731 00:43:03,760 --> 00:43:06,279 Speaker 1: always facing towards the hot side of the planet, and 732 00:43:06,280 --> 00:43:08,440 Speaker 1: the other eye needs to be very sensitive because it's 733 00:43:08,480 --> 00:43:11,520 Speaker 1: always facing towards the dark side. I don't know, Oh 734 00:43:11,560 --> 00:43:13,839 Speaker 1: that's interesting. Uh yeah, I mean I guess that would 735 00:43:13,880 --> 00:43:16,319 Speaker 1: be the region that you a life form might be 736 00:43:16,480 --> 00:43:20,279 Speaker 1: likely to to live in because you would have less 737 00:43:20,280 --> 00:43:23,879 Speaker 1: of an extreme of heat or cold. But of course 738 00:43:23,880 --> 00:43:27,080 Speaker 1: it would also be a like a chaotic region as well. 739 00:43:27,160 --> 00:43:30,600 Speaker 1: You would have probably have a lot of climactic weather 740 00:43:30,800 --> 00:43:33,359 Speaker 1: going on there. It's highly locked planet. It's probably not 741 00:43:33,400 --> 00:43:36,480 Speaker 1: great for goats. But I was just trying to imagine, 742 00:43:36,760 --> 00:43:39,200 Speaker 1: you know, that that's conceivably that's the kind of environment 743 00:43:39,239 --> 00:43:42,799 Speaker 1: that might require some sort of drastic change in the 744 00:43:42,840 --> 00:43:46,840 Speaker 1: positioning of the eyes and the specialization of the eyes. Um, 745 00:43:46,880 --> 00:43:48,960 Speaker 1: I mean it I feel like we I mean, we're 746 00:43:48,960 --> 00:43:53,120 Speaker 1: so hardwired for our surface world environment. It is difficult 747 00:43:53,480 --> 00:43:55,520 Speaker 1: for us. It's it's a little challenging to put ourselves 748 00:43:55,520 --> 00:43:59,040 Speaker 1: in the mindset and ultimately the the ocular world of 749 00:43:59,080 --> 00:44:02,000 Speaker 1: something like a goat or something like a you know, 750 00:44:02,040 --> 00:44:06,000 Speaker 1: a purely predatory cat or something much less, to put 751 00:44:06,000 --> 00:44:09,080 Speaker 1: ourselves in the mind said, in the ocular world of 752 00:44:09,160 --> 00:44:11,840 Speaker 1: the squid or or you know, to get into the 753 00:44:11,880 --> 00:44:15,200 Speaker 1: sense worlds of whales and so forth. It's, uh, you know, 754 00:44:15,280 --> 00:44:19,160 Speaker 1: it's it's it's a different environment altogether. And these environments, 755 00:44:19,160 --> 00:44:22,640 Speaker 1: as we see from these examples, we've looked like they 756 00:44:22,680 --> 00:44:25,160 Speaker 1: almost literally can pull us in in half. You know, 757 00:44:25,239 --> 00:44:28,600 Speaker 1: they can they can change it. They can break whatever 758 00:44:29,120 --> 00:44:33,600 Speaker 1: uh seeming symmetry was there in the body originally as 759 00:44:33,640 --> 00:44:37,240 Speaker 1: it adapts, as it evolves to fit this environment over time. 760 00:44:38,440 --> 00:44:40,640 Speaker 1: This raises a question that comes to my mind actually 761 00:44:40,719 --> 00:44:43,239 Speaker 1: quite often, uh, when you think about, like if there 762 00:44:43,239 --> 00:44:48,000 Speaker 1: were other clades of animals that that became very intelligent 763 00:44:48,160 --> 00:44:51,680 Speaker 1: and had something like art what would what would they 764 00:44:51,680 --> 00:44:54,359 Speaker 1: find beautiful and how would it be different from what 765 00:44:54,400 --> 00:44:59,600 Speaker 1: we find beautiful based on on our brains and our biology. Yeah, 766 00:44:59,640 --> 00:45:02,040 Speaker 1: but I maybe we're gonna have to call the first 767 00:45:02,080 --> 00:45:05,359 Speaker 1: episode there. We will certainly be back with with more 768 00:45:05,400 --> 00:45:08,640 Speaker 1: marvels of asymmetry, and in subsequent episodes we're gonna talk 769 00:45:08,680 --> 00:45:12,120 Speaker 1: about uh, crabs and crustaceans, and I think we'll talk 770 00:45:12,160 --> 00:45:15,160 Speaker 1: about snakes some probably come back to some fish and 771 00:45:15,520 --> 00:45:21,200 Speaker 1: maybe some larger developmental theoretical concerns about where asymmetry comes from. 772 00:45:21,200 --> 00:45:25,480 Speaker 1: In in the Kingdoms of Life. That's right. Uh. In 773 00:45:25,520 --> 00:45:27,640 Speaker 1: the meantime, you can check out other episodes of Stuff 774 00:45:27,680 --> 00:45:29,120 Speaker 1: to Blow Your Mind and the Stuff to Blow Your 775 00:45:29,120 --> 00:45:31,879 Speaker 1: Mind podcast feed, which you can find wherever you get 776 00:45:31,920 --> 00:45:36,400 Speaker 1: your podcast. Tuesdays and Thursdays are our core episodes. Uh. 777 00:45:36,480 --> 00:45:39,800 Speaker 1: We have a short form artifact or monster fact on Wednesday, 778 00:45:39,880 --> 00:45:42,680 Speaker 1: Little listener mail on Monday, and and then on Friday 779 00:45:42,760 --> 00:45:44,600 Speaker 1: we do Weird How Cinema. That's our time to set 780 00:45:44,600 --> 00:45:48,279 Speaker 1: aside most serious concerns and just talk about a strange film. 781 00:45:48,440 --> 00:45:51,359 Speaker 1: Huge thanks as always to our excellent audio producer Seth 782 00:45:51,440 --> 00:45:53,839 Speaker 1: Nicholas Johnson. If you would like to get in touch 783 00:45:53,880 --> 00:45:56,160 Speaker 1: with us with feedback on this episode or any other, 784 00:45:56,239 --> 00:45:58,279 Speaker 1: to suggest a topic for the future, or just to 785 00:45:58,320 --> 00:46:00,920 Speaker 1: say hello, you can email us at contact. That's Stuff 786 00:46:00,960 --> 00:46:10,600 Speaker 1: to Blow Your Mind dot com. Stuff to Blow Your 787 00:46:10,600 --> 00:46:13,520 Speaker 1: Mind is production of I Heart Radio. For more podcasts 788 00:46:13,560 --> 00:46:15,640 Speaker 1: for my heart Radio, visit the i heart Radio app, 789 00:46:15,800 --> 00:46:27,319 Speaker 1: Apple Podcasts, or wherever you're listening to your favorite shows.