WEBVTT - From the Vault: The Glorious Hermit Crab, Part 3 0:00:06.480 --> 0:00:09.479 Hello, and welcome to Stuff to Blow Your Mind. I 0:00:09.520 --> 0:00:13.039 am Joe McCormick. Normally on Tuesdays we would have a 0:00:13.119 --> 0:00:15.480 new core episode of the show for you, but our 0:00:15.520 --> 0:00:17.680 team has some stuff going on early this week, so 0:00:17.760 --> 0:00:21.400 today we are bringing you an episode from the vault. 0:00:21.760 --> 0:00:24.599 This is part three of our series on the Hermit 0:00:24.680 --> 0:00:28.600 Crab and it originally aired on January eleventh, twenty twenty four. 0:00:29.360 --> 0:00:31.520 After today's vault, we're going to be back with all 0:00:31.560 --> 0:00:34.479 new stuff for you the rest of this week. So 0:00:34.720 --> 0:00:38.879 I guess that's everything. Let us seize the empty shell. 0:00:41.159 --> 0:00:44.159 Welcome to Stuff to Blow Your Mind, the production of iHeartRadio. 0:00:51.240 --> 0:00:52.880 Hey, welcome to Stuff to Blow Your Mind. 0:00:53.000 --> 0:00:56.000 My name is Robert Lamb and I am Joe McCormick, 0:00:56.040 --> 0:00:59.080 and we are back with part three in our series 0:00:59.160 --> 0:01:02.560 on Hermit Crabs. Now, if you haven't heard the first 0:01:02.600 --> 0:01:04.240 couple of parts of the series, you might want to 0:01:04.240 --> 0:01:07.480 go back and listen to those first, but also if 0:01:07.560 --> 0:01:09.360 you just want to start here, that's fine. I don't 0:01:09.360 --> 0:01:11.440 know if there's any particular order you need to do 0:01:11.520 --> 0:01:15.440 these in. In the previous two episodes, we talked about 0:01:15.920 --> 0:01:20.760 Rob's recent in person observation of terrestrial Caribbean hermit crabs 0:01:20.800 --> 0:01:24.360 in the wild, which sounds fascinating watching them scuttle about 0:01:24.400 --> 0:01:27.679 and do their business. We talked about the way hermit 0:01:27.720 --> 0:01:31.080 crabs fit into the crustacean family tree, how they differ 0:01:31.160 --> 0:01:35.399 from so called true crabs or the brachyura, how they 0:01:35.400 --> 0:01:39.640 evolved to depend on exogynous mobile shelter in the form 0:01:39.680 --> 0:01:43.559 of things like gastropod shells. We talked about how hermit 0:01:43.600 --> 0:01:47.319 crabs forage and compete for shells within a kind of economy, 0:01:47.760 --> 0:01:52.080 and how this leads to an interesting phenomenon called vacancy chains, 0:01:52.160 --> 0:01:57.120 with parallels in the markets for some certain human resources, 0:01:57.160 --> 0:02:00.920 such as housing and certain kinds of jobs. We discussed 0:02:00.920 --> 0:02:05.400 some surprising evolutionary relationships, such as the widely supported idea 0:02:05.520 --> 0:02:10.040 that free living king crabs, yes, even the kind you eat, 0:02:10.520 --> 0:02:15.080 probably evolved from a hermit crab ancestor so the lineage. 0:02:15.280 --> 0:02:18.600 If this hypothesis is right, the lineage evolved once from 0:02:18.800 --> 0:02:22.280 free living crabs to the hermit crab form, where it 0:02:22.360 --> 0:02:26.959 developed a soft wormy abdomen and evolved to depend entirely 0:02:27.000 --> 0:02:30.600 on these externally sourced shells, and then some branches of 0:02:30.600 --> 0:02:34.960 that family evolved once again to abandon the external shells 0:02:35.120 --> 0:02:38.640 and become fully hardened all over, become these free living 0:02:38.919 --> 0:02:43.639 crab like organisms. Again, king crabs are also anomura. They're 0:02:43.680 --> 0:02:47.399 also not so called true crabs. And also we discussed 0:02:47.440 --> 0:02:51.680 some fascinating alternatives to the common relationship between hermit crabs 0:02:51.720 --> 0:02:56.120 and snail shells. The majority of crabs do hermit crabs 0:02:56.160 --> 0:02:59.960 do prefer to live within the shells of gastropods, snails, welks, periwinkles, 0:03:00.040 --> 0:03:02.600 those kind of things. But there are also hermits that 0:03:02.680 --> 0:03:06.880 take up residents within living sea anemones or solitary corals, 0:03:07.280 --> 0:03:10.079 and so we talked about the reasons those relationships could 0:03:10.120 --> 0:03:11.440 be mutually beneficial. 0:03:11.639 --> 0:03:14.519 That's right, And as we discussed too, I mean, there's 0:03:14.520 --> 0:03:17.520 still so much research going on concerning hermit crabs and 0:03:17.680 --> 0:03:21.480 the discovery of new particularly aquatic hermit crab species, and 0:03:21.639 --> 0:03:25.160 just fully understanding terrestrial hermit crabs as well. So you know, 0:03:25.160 --> 0:03:26.840 we're gonna we're not going to be able to touch 0:03:26.880 --> 0:03:29.520 on everything in this trilogy, but we are going to 0:03:29.520 --> 0:03:32.720 finish the trilogy here. We're going to finish our story 0:03:32.960 --> 0:03:35.800 of hermit crabs, and we're going to get into a 0:03:35.840 --> 0:03:38.760 few remaining and perhaps surprising areas of discussion. 0:03:39.120 --> 0:03:41.640 So the first thing I wanted to talk about today 0:03:42.520 --> 0:03:46.080 was that I was quite interested to find some meditations 0:03:46.080 --> 0:03:49.840 on hermit crabs in the writings of the late Stephen J. Gould, 0:03:50.040 --> 0:03:55.640 the American paleontologist and popular science communicator. So, first of all, 0:03:55.800 --> 0:03:58.240 I did find that Gould wrote a good bit on 0:03:58.520 --> 0:04:01.240 the hermits to King's hypod thesis that we talked about 0:04:01.280 --> 0:04:05.200 in the previous episode, where king crabs are thought to 0:04:05.280 --> 0:04:08.040 have probably evolved from hermit crab ancestors. 0:04:08.920 --> 0:04:11.120 Did he have a particular take or was he just 0:04:11.400 --> 0:04:15.960 generally reporting on the back and forth among evolutionary scientists. 0:04:16.400 --> 0:04:18.640 Well, I saw that he wrote on this subject. I 0:04:18.640 --> 0:04:20.919 did not read everything he did right on this subject, 0:04:20.920 --> 0:04:22.560 so I don't know where he landed in the end. 0:04:23.400 --> 0:04:25.320 I'm just going to assume he probably landed where everyone 0:04:25.320 --> 0:04:27.640 else seems to be in the land, and that is well, 0:04:27.800 --> 0:04:32.520 most people agree that this hypothesis has probably corrected. It 0:04:32.560 --> 0:04:34.400 seems to be the scientific consensus. 0:04:34.680 --> 0:04:38.440 That seems likely to me. But beyond that, I found 0:04:38.520 --> 0:04:42.400 a really interesting anecdote about hermit crabs in an essay 0:04:42.640 --> 0:04:47.599 called Nature's Odd couples from Gould's nineteen eighty collection The 0:04:47.680 --> 0:04:52.520 Panda's Thumb. This essay was great because the core observations 0:04:52.520 --> 0:04:55.200 from Gould are fascinating, but it also sent me off 0:04:55.200 --> 0:04:58.680 on a pretty good tangent that I hope you'll enjoy 0:04:58.720 --> 0:05:04.440 about snail's what look like bloody teeth. So Gould opens 0:05:04.560 --> 0:05:08.080 this essay with a quote. He opens by talking about 0:05:08.160 --> 0:05:12.760 a quote from Alexander Pope's poem An Essay on Man 0:05:12.920 --> 0:05:17.559 and a rhyming couplet. It goes like this, from nature's chain, 0:05:17.720 --> 0:05:21.760 whatever link you strike tenth or ten thousandth breaks the 0:05:21.880 --> 0:05:24.960 chain alike, And he kind of starts by appreciating some 0:05:25.000 --> 0:05:27.840 ways in which this quote is both is and is 0:05:27.920 --> 0:05:31.760 not true. So in the sense in which the spirit 0:05:31.800 --> 0:05:35.760 of the quote is true, organisms throughout an ecosystem are 0:05:35.920 --> 0:05:41.360 all connected by various types of relationships. There are energy relationships, 0:05:41.400 --> 0:05:45.320 you know, some organisms eat one another or affect how 0:05:45.400 --> 0:05:49.760 one another can acquire energy. There are information relationships. Sometimes 0:05:49.880 --> 0:05:53.640 organisms learn about something from another one and so forth, 0:05:53.960 --> 0:05:57.520 and these relationships can be both direct and indirect, So 0:05:57.720 --> 0:06:00.320 things that happen to one organism can ripple through the 0:06:00.320 --> 0:06:04.680 whole ecosystem. In surprising ways. On the other hand, it's 0:06:04.760 --> 0:06:08.320 obviously not the case that the chain of nature to 0:06:08.400 --> 0:06:12.719 use Pope's image here, is completely destroyed anytime one link 0:06:12.839 --> 0:06:17.799 is broken Gould rights quote. Ecosystems are not so precariously 0:06:17.839 --> 0:06:21.960 balanced that the extirpation of one species must act like 0:06:22.520 --> 0:06:27.200 the first domino in that colorful metaphor of the Cold War. Indeed, 0:06:27.360 --> 0:06:30.559 it could not be, for extinction is the common fate 0:06:30.760 --> 0:06:34.960 of all species, and they cannot all take their ecosystems 0:06:34.960 --> 0:06:38.280 with them. Species often have as much dependence on each 0:06:38.279 --> 0:06:42.400 other as longfellows ships that pass in the night. And 0:06:42.440 --> 0:06:44.279 to add to this, I would just say it's a 0:06:44.360 --> 0:06:47.080 very safe estimate that more than ninety nine percent of 0:06:47.120 --> 0:06:51.679 species that have ever existed are already extinct. The American 0:06:51.720 --> 0:06:54.320 Museum of Natural History uses the estimate that it's more 0:06:54.360 --> 0:06:57.159 than ninety nine point nine percent of all species that 0:06:57.200 --> 0:07:00.440 ever existed. So obviously it's just not the case that 0:07:00.920 --> 0:07:04.359 a single link is broken and the entire chain is 0:07:04.520 --> 0:07:09.080 necessarily shattered, or life couldn't exist today. Ecosystems in many 0:07:09.160 --> 0:07:13.160 cases survive and adapt that they have to change. They 0:07:13.200 --> 0:07:16.440 adapt to changes in their makeup, but to come back 0:07:16.480 --> 0:07:19.960 On the other hand, it's absolutely true that the extinction 0:07:20.080 --> 0:07:24.320 of one organism in an ecosystem can be absolutely devastating, 0:07:24.440 --> 0:07:27.640 and it can lead to secondary extinctions. And from a 0:07:27.760 --> 0:07:31.720 human perspective, a major danger here is the lack of 0:07:31.760 --> 0:07:35.600 predictability in these kinds of relationships, Like sometimes we can 0:07:35.680 --> 0:07:39.560 predict what these relationships and domino effects would be, but 0:07:39.640 --> 0:07:43.600 sometimes we can't. We don't always know what would happen 0:07:43.720 --> 0:07:46.840 to a whole environment and ecosystem when one species is 0:07:46.880 --> 0:07:47.880 taken out of the equation. 0:07:48.600 --> 0:07:50.880 That's right, and we've talked about that before in terms 0:07:50.920 --> 0:07:53.840 of situations where there is very much an organism we 0:07:53.880 --> 0:07:58.520 would like to remove from the ecosystem or from parts 0:07:58.560 --> 0:08:02.560 of the ecosystem, such as say mosquito or some other paths, 0:08:02.560 --> 0:08:07.880 something that is interfering with human aims and industries. But 0:08:08.040 --> 0:08:11.040 the question always remains, like, well, what else is that 0:08:11.360 --> 0:08:14.520 organism doing, What eats it, what is kept in check 0:08:14.600 --> 0:08:16.560 by it, and so forth, And so there are all 0:08:16.560 --> 0:08:19.240 these spiraling concerns, and you know, it's kind of like that. 0:08:20.040 --> 0:08:22.200 It reminds me of that old thing I think from 0:08:22.240 --> 0:08:24.560 some movie or another about how if you're going to 0:08:25.040 --> 0:08:27.840 rob a bank or something you know. They're like so 0:08:27.920 --> 0:08:29.600 many ways you can mess up, and if you can 0:08:29.640 --> 0:08:31.200 think of like three of them, you're a genius. It 0:08:31.560 --> 0:08:36.000 seems like a similar situation anytime humans want to mess 0:08:36.080 --> 0:08:39.960 with the ecosystem with the introduction or removal of certain species. 0:08:40.240 --> 0:08:42.480 They are the things that you know can occur or 0:08:42.760 --> 0:08:45.240 likely will occur if you change it. But then there 0:08:45.240 --> 0:08:48.600 are all these additional ripple effects that you cannot necessarily predict. 0:08:49.040 --> 0:08:51.600 Right, So it's not the case that breaking one link 0:08:51.600 --> 0:08:54.040 in the chain necessarily shatters the whole chain, but it 0:08:54.080 --> 0:08:56.680 does change the chain, and you might not like the 0:08:56.679 --> 0:08:59.800 way it changes. Yeah, So we don't always know what's 0:08:59.800 --> 0:09:01.920 going to happen when one species is taken out of 0:09:01.920 --> 0:09:04.800 the equation, and in fact, we can assume the organisms 0:09:04.880 --> 0:09:08.200 in question don't know either. And what's more than that, 0:09:08.520 --> 0:09:12.320 the algorithm of evolution itself, in the metaphorical sense that 0:09:12.400 --> 0:09:15.040 it can know anything, cannot be said to know in 0:09:15.120 --> 0:09:18.880 advance what will result from extinctions, which is why so 0:09:19.000 --> 0:09:26.480 many organisms evolve sort of dangerous precarious relationships. May in 0:09:26.480 --> 0:09:33.119 many cases, organisms evolve unbreakable dependencies on another specific organism. 0:09:33.559 --> 0:09:37.160 For example, a predator that is specialized to eat only 0:09:37.200 --> 0:09:40.600 one type of prey. If that prey organism disappears, the 0:09:40.600 --> 0:09:44.360 predator is doomed. Or a plant that relies on a 0:09:44.440 --> 0:09:48.679 specific animal to help it pollinate and reproduce. One common 0:09:48.720 --> 0:09:51.960 example cited here are yucca plants and yucca moths, which 0:09:52.120 --> 0:09:55.360 both rely on one another in a system known as 0:09:55.440 --> 0:09:59.239 obligate mutualism. You know, yucca plants have to be pollinated 0:09:59.280 --> 0:10:02.720 by yukama and yuka moth larvae grow in the yucca 0:10:02.720 --> 0:10:05.200 plants and grow by eating some, but not all, of 0:10:05.240 --> 0:10:08.599 the yucca seeds. And though with the yucca plant the 0:10:08.679 --> 0:10:12.160 yuca moth the relationship goes both ways, some of these 0:10:12.160 --> 0:10:15.760 relationships don't go both ways. Sometimes they're only one way. Again, 0:10:15.679 --> 0:10:19.240 the predator that can only eat one species for food. 0:10:20.000 --> 0:10:25.320 So while these highly dependent relationships can be helpful specializations 0:10:25.400 --> 0:10:28.560 at a specific time in a specific environment, they're good 0:10:28.559 --> 0:10:31.920 for helping you survive. Now, they're sort of analogous to 0:10:32.000 --> 0:10:35.040 like putting all of your life savings in a single stock. 0:10:35.280 --> 0:10:38.040 You know, like if the company's doing well, that's great 0:10:38.040 --> 0:10:40.520 for you, but if it goes bankrupt, you lose everything. 0:10:41.360 --> 0:10:45.439 And sometimes evolution selects for creatures that do not have 0:10:45.520 --> 0:10:48.960 diverse survival strategies, you know, they're all in on a 0:10:49.040 --> 0:10:52.520 single ecological partner. And this brings us back to Gould's 0:10:52.600 --> 0:10:55.120 essay where he talks about a couple of examples where 0:10:55.120 --> 0:10:58.280 we see what happens to a pair of species that 0:10:59.000 --> 0:11:01.600 either depend on each other or one depends on the 0:11:01.640 --> 0:11:05.400 other in this way the odd couples of the essays 0:11:05.440 --> 0:11:10.199 title what happens to them after a sudden disruption? And 0:11:10.320 --> 0:11:12.559 one of the examples he talks about is a hermit crab. 0:11:13.040 --> 0:11:16.080 So Gould recounts some of his days as a graduate 0:11:16.120 --> 0:11:19.360 student when he was writing his PhD dissertation on the 0:11:19.440 --> 0:11:23.080 land snails of Bermuda. So he was in Bermuda, and 0:11:23.120 --> 0:11:25.320 he says while he was exploring the shores and the 0:11:25.360 --> 0:11:29.560 beaches there, he would quite often come across hermit crabs, 0:11:29.600 --> 0:11:33.880 but not just any hermit crabs, large hermit crabs crammed 0:11:33.920 --> 0:11:36.880 into a shell that was way too small for them. 0:11:36.920 --> 0:11:40.720 He would talk about, like their big claw protruding out 0:11:40.760 --> 0:11:44.520 of the shell. And he says that these tiny shells 0:11:44.559 --> 0:11:48.040 that they were trying to fit into were shells of 0:11:48.080 --> 0:11:52.920 the narrated snail, which he points out includes what he 0:11:53.000 --> 0:11:56.040 calls quote the familiar bleeding tooth. 0:11:56.679 --> 0:11:57.199 That was not. 0:11:57.240 --> 0:11:59.160 Familiar to me. I had no idea what he's talking 0:11:59.160 --> 0:12:01.280 about with the bleed tooth there. I had to look 0:12:01.280 --> 0:12:03.360 that up, and so I'll come back to that in 0:12:03.360 --> 0:12:03.960 a minute. 0:12:04.400 --> 0:12:05.079 I can't wait. 0:12:05.320 --> 0:12:08.880 But on the general subject of the narratid snails, this 0:12:08.920 --> 0:12:11.320 is a fairly lengthy digression, but I had to look 0:12:11.400 --> 0:12:13.600 up this animal because they came up a couple of times. 0:12:13.640 --> 0:12:16.840 We talked about narratids in the first episode of this series, 0:12:17.280 --> 0:12:19.599 and I didn't really know anything about them. So I 0:12:19.640 --> 0:12:23.359 looked them up and I found some interesting backstory. Narratids 0:12:23.600 --> 0:12:28.319 or Nartes are named after a minor sea god from 0:12:28.400 --> 0:12:32.839 Greek mythology who was called Narraties, and it seems that 0:12:32.920 --> 0:12:35.840 the main written source on the narratives myths is the 0:12:35.960 --> 0:12:40.000 second to third century Roman author Alien in his book 0:12:40.360 --> 0:12:44.040 on the Nature of Animals. I think this specific text 0:12:44.120 --> 0:12:46.800 came up in a series we did not too long 0:12:46.800 --> 0:12:51.199 ago on beavers, because Alien is the source of the 0:12:51.240 --> 0:12:54.480 ancient story about how male beavers would bite off their 0:12:54.480 --> 0:12:57.079 own testicles and offer them up to hunters to make 0:12:57.080 --> 0:12:59.920 the hunter stop chasing them. I believe we judge this 0:13:00.040 --> 0:13:03.640 story not true. But Alien has a lot of interesting 0:13:03.720 --> 0:13:07.680 animal facts of that kind. But he also has some 0:13:07.880 --> 0:13:11.400 backstory on the narrated sea snails. So I'm going to 0:13:11.480 --> 0:13:14.760 alternately quote from and summarize Alien's text here. This is 0:13:14.760 --> 0:13:19.520 from the af Skolfield translation of Aliens on the nature 0:13:19.559 --> 0:13:22.680 of animals. He writes, quote, there is in the sea 0:13:22.800 --> 0:13:26.440 a shellfish with a spiral shell, small in size but 0:13:26.520 --> 0:13:29.840 of surpassing beauty. And it is born where the water 0:13:30.000 --> 0:13:32.880 is at it's purest, and upon rocks beneath the sea, 0:13:33.320 --> 0:13:37.319 and on what are called sunken reefs. Its name is Nrites. 0:13:38.600 --> 0:13:40.880 Then this was funny. He goes on to make some 0:13:41.040 --> 0:13:44.360 excuses for why it is okay that he's about to 0:13:44.400 --> 0:13:46.280 tell a couple of stories in the middle of this 0:13:46.480 --> 0:13:48.880 very serious book. He says, it is going to sweeten 0:13:48.960 --> 0:13:49.400 the work. 0:13:49.559 --> 0:13:52.600 So okay, Yeah, like a little bit of a little 0:13:52.600 --> 0:13:55.560 bit of lead sprinkled into your wine, right. 0:13:55.720 --> 0:14:00.120 Exactly, Yeah, the lead sugar. So anyway, there are two 0:14:00.160 --> 0:14:02.840 stories about how this animal came to exist, and in 0:14:02.880 --> 0:14:07.199 both cases the stories trace back to an extremely handsome, 0:14:07.400 --> 0:14:11.760 hyper hunk deity named Nerides, who is the son of 0:14:11.880 --> 0:14:16.680 the sea god Nereus and of the sea goddess Doris, 0:14:16.800 --> 0:14:21.240 the daughter of Okeanos. So in the first story we 0:14:21.400 --> 0:14:25.600 learned that Narides was so overwhelmingly handsome that he became 0:14:25.640 --> 0:14:29.000 the favorite of the goddess Aphrodite, and she fell in 0:14:29.040 --> 0:14:32.440 love with him. And Elien writes quote, and when the 0:14:32.440 --> 0:14:35.560 faded time arrived, at which at the bidding of the 0:14:35.600 --> 0:14:39.240 father of the gods, Aphrodite also had to be enrolled 0:14:39.280 --> 0:14:42.880 among the Olympians. I have heard that she ascended and 0:14:43.040 --> 0:14:47.960 wished to bring her companion and playfellow Benrides. But the 0:14:48.000 --> 0:14:52.080 story goes that he refused, preferring life with his sisters 0:14:52.080 --> 0:14:55.480 and parents to Olympus. And then he was permitted to 0:14:55.560 --> 0:14:59.160 grow wings. This I imagine was a gift from Aphrodite. 0:14:59.440 --> 0:15:02.640 But even this favor he counted as nothing. And so 0:15:02.920 --> 0:15:06.000 the daughter of Zeus was moved to anger and transformed 0:15:06.040 --> 0:15:09.720 his shape into this shell, and if her own accord, 0:15:10.040 --> 0:15:13.520 chose in his place for her attendant and servant, Aros, 0:15:13.920 --> 0:15:16.480 who was also young and beautiful, and to him she 0:15:16.640 --> 0:15:19.040 gave the wings of Narrites. 0:15:19.920 --> 0:15:23.440 Very spiteful, like, very much like, much like her father. 0:15:24.040 --> 0:15:27.440 That that's true. So Narides liked his home in the sea. 0:15:27.480 --> 0:15:30.280 He was not ready to move in with Aphrodite's family 0:15:30.400 --> 0:15:33.520 on the mountain. So, you know, even though she gave 0:15:33.600 --> 0:15:36.040 him wings and everything, he didn't want to budge. So 0:15:36.160 --> 0:15:39.440 she transformed him into a sea snail out of revenge. 0:15:39.520 --> 0:15:43.200 And it's interesting it says specifically that he was transformed 0:15:43.240 --> 0:15:46.320 into the shell. I assume that means the whole animal, 0:15:46.400 --> 0:15:48.360 including the snail. It would be funny if it just 0:15:48.400 --> 0:15:50.680 transformed him into the shell and a snail had to 0:15:50.720 --> 0:15:54.120 live in him. 0:15:52.720 --> 0:15:54.680 But that would very much fit with a lot of 0:15:54.680 --> 0:15:56.040 what we've been talking about with hermikers. 0:15:56.680 --> 0:16:00.280 I guess that's true, And so this story kind of 0:16:00.600 --> 0:16:04.400 matches the general form of these Greco Roman metamorphosis stories. 0:16:04.440 --> 0:16:06.720 You know, somebody offends a god in some way and 0:16:06.720 --> 0:16:10.280 they're transformed into something else. But I was wondering, like 0:16:10.360 --> 0:16:13.120 why a snail in particular. I'm not sure if I'm 0:16:13.200 --> 0:16:16.520 missing something about this story, but I feel like Alien's 0:16:16.640 --> 0:16:19.840 next story has a little bit more of a hint 0:16:19.880 --> 0:16:22.680 about that element, like why he would be transformed into 0:16:22.680 --> 0:16:27.080 a snail. So the next story starts the same Nerides 0:16:27.200 --> 0:16:31.120 was a young, extremely handsome see god, but this time 0:16:31.520 --> 0:16:34.240 instead of becoming the favorite of Aphrodite, he becomes the 0:16:34.240 --> 0:16:40.480 favorite of Poseidon, and he becomes Poseidon's chariotear so, Elian 0:16:40.520 --> 0:16:43.600 writes quote when Poseidon drove his chariot over the waves, 0:16:43.720 --> 0:16:47.240 all other great fishes, as well as dolphins and tritons too, 0:16:47.800 --> 0:16:51.400 sprang up from their deep haunts and gamboled and danced 0:16:51.440 --> 0:16:54.440 around the chariot, only to be left utterly and far 0:16:54.560 --> 0:16:57.720 behind by the speed of his horses. Only the boy 0:16:57.800 --> 0:17:01.640 favorite was his escort close at hand, and before them 0:17:01.720 --> 0:17:04.800 the waves sank to rest, and the sea parted out 0:17:04.840 --> 0:17:08.040 of reverence to Poseidon, for the god willed that his 0:17:08.160 --> 0:17:12.160 beautiful favorite should not only be highly esteemed for other reasons, 0:17:12.200 --> 0:17:16.679 but should also be pre eminent at swimming. But the 0:17:16.720 --> 0:17:20.040 story goes from here that Helios, the sun god, was 0:17:20.280 --> 0:17:24.679 jealous of the speed of Neriodes and transformed him into 0:17:25.000 --> 0:17:29.240 the snail with the spiral shell. And Helian says, commenting 0:17:29.320 --> 0:17:32.040 on the story here, that he doesn't know why Helios 0:17:32.119 --> 0:17:35.639 was angry at Nridies, but guesses that either Poseidon and 0:17:35.720 --> 0:17:40.359 Helios are enemies, or perhaps that Helios was jealous that 0:17:41.440 --> 0:17:44.359 the handsome guy was down in the sea. With Poseidon 0:17:44.680 --> 0:17:47.040 instead of flying among the stars with him. 0:17:47.359 --> 0:17:50.960 Yeah, I mean, really standard god drama right here. 0:17:52.200 --> 0:17:56.280 But exactly. But in this version at least, Nrides is 0:17:56.320 --> 0:17:59.439 known for being fast, right, so he's fast, and then 0:17:59.480 --> 0:18:03.560 he's trans formed into a snail. Something seems more fittingly 0:18:03.600 --> 0:18:05.199 ironic about that punishment. 0:18:05.560 --> 0:18:06.840 Oh yes, yes, you're right. 0:18:07.359 --> 0:18:11.600 Remember Aristotle actually mentions narrities when he's talking about the 0:18:11.880 --> 0:18:16.439 shells that hermit crabs occupy. But anyway, these snails today, 0:18:16.520 --> 0:18:19.240 they are a family of gastropods that are found in 0:18:19.520 --> 0:18:22.120 all types of water. They're found in freshwater, brackish water, 0:18:22.200 --> 0:18:25.960 and salt water. Their diet most of the time consists 0:18:26.040 --> 0:18:28.840 of algae that they eat off of rock surfaces and 0:18:28.880 --> 0:18:31.119 the waters that crawl around on a rock sort of 0:18:31.160 --> 0:18:33.760 scraping up algae and eating it. And they tend to 0:18:33.800 --> 0:18:37.800 be pretty small. They're sort of considered small to medium snails. 0:18:38.359 --> 0:18:41.919 So it is quite pitiable to imagine, as Gould describes, 0:18:42.320 --> 0:18:46.080 a population of hermit crabs where even fairly large individuals 0:18:46.119 --> 0:19:00.360 are trying desperately to cram into these tiny shells. Now, 0:19:00.440 --> 0:19:01.679 the one thing I said it was going to come 0:19:01.720 --> 0:19:05.080 back to was that nearte that Gould mentions by name 0:19:05.160 --> 0:19:08.879 in his essay the so called bleeding tooth, he doesn't 0:19:08.880 --> 0:19:11.080 say anything else about it. So I got curious about 0:19:11.080 --> 0:19:13.080 this as well, and I found a good photo with 0:19:13.119 --> 0:19:17.320 some interpretive text on the website for the Bailey Matthews 0:19:17.480 --> 0:19:21.520 National Shell Museum in Florida, USA. Rob I attached the 0:19:21.560 --> 0:19:24.000 pictures for you to look at here. And first of all, 0:19:24.040 --> 0:19:27.000 I gotta give credit to whoever named this, because they're 0:19:27.400 --> 0:19:29.480 right on the money. It does look like a pair 0:19:29.520 --> 0:19:31.760 of bloody teeth. Absolutely disgusting. 0:19:32.320 --> 0:19:34.960 This is easily the most disgusting shell I've ever seen. 0:19:35.040 --> 0:19:37.320 Usually I'm a big shell fan. Yeah, no matter what 0:19:37.400 --> 0:19:39.399 kind of creature lives inside it, Like show me the 0:19:39.400 --> 0:19:42.560 shell and yeah, it's generally pretty stunning, or even a 0:19:42.680 --> 0:19:46.359 very plain shell is pleasant to behold. This this is gross. 0:19:46.400 --> 0:19:54.080 This looks like misshapen teeth emerging from inflamed and recessed gums. 0:19:53.880 --> 0:19:56.639 It's what like the dentist would scare the children with 0:19:56.720 --> 0:19:57.560 on The Simpsons. 0:19:58.160 --> 0:20:01.800 Yeah, yeah, you'll see brochures with images like this. Yeah, 0:20:01.920 --> 0:20:04.320 your local dentist office makes me kind of want to 0:20:04.720 --> 0:20:09.439 make a fake brochure with images of the shell and 0:20:09.520 --> 0:20:12.560 just sort of slip them in among the other brochures 0:20:12.560 --> 0:20:13.040 next time I go. 0:20:13.080 --> 0:20:15.359 It makes me want to leave this session and go 0:20:15.480 --> 0:20:17.040 like brush and floss right now. 0:20:17.760 --> 0:20:20.960 Yeah, we can take five dental. 0:20:20.760 --> 0:20:25.720 Health anyway, so yeah, you can look these up. The 0:20:26.040 --> 0:20:30.320 bleeding tooth near eight. Anyway, This is on the inside 0:20:30.359 --> 0:20:32.280 of the shell orifice. You can imagine it's kind of 0:20:32.320 --> 0:20:35.440 a spiral and it's got the opening. So if you're 0:20:35.480 --> 0:20:40.199 looking at the opening, the side of the aperture that 0:20:40.320 --> 0:20:43.879 is closest to the central column or axis of the shell, 0:20:44.000 --> 0:20:47.560 that's where the bloody looking teeth are. And the museum 0:20:47.600 --> 0:20:52.600 page says that this is the species Narida pelloranta, and 0:20:52.680 --> 0:20:55.640 it's a snail commonly found on shores throughout the Caribbean 0:20:55.720 --> 0:20:59.280 and Florida. It reaches a maximum of about two inches 0:20:59.359 --> 0:21:03.119 or about fifty millimeters in size, and in an interesting 0:21:03.280 --> 0:21:07.200 parallel to the shell remodeling we saw in some land 0:21:07.280 --> 0:21:12.000 dwelling hermit crabs, the bleeding tooth snail will sometimes dissolve 0:21:12.119 --> 0:21:15.960 the interior surfaces of its own shell to give itself 0:21:16.040 --> 0:21:19.600 more space inside and also to make room for a 0:21:19.720 --> 0:21:22.960 kind of a water tank reserve, to make room to 0:21:23.119 --> 0:21:26.840 retain reserves of water inside the shell, which is apparently 0:21:26.920 --> 0:21:29.760 useful for the snail during low tide. 0:21:30.280 --> 0:21:33.000 Yeah. Yeah, this is essential to what we were talking 0:21:33.040 --> 0:21:35.480 about in the first episode here on hermit crabs, about 0:21:35.520 --> 0:21:39.919 the chemical and physical augmentation of the shells that hermit 0:21:39.960 --> 0:21:42.879 crabs use. And so most of the shells that hermit 0:21:42.920 --> 0:21:46.880 crabs are competing for have been augmented, have been remodeled. 0:21:47.320 --> 0:21:50.119 Yeah, and it's interesting that I think we've uncovered at 0:21:50.200 --> 0:21:54.439 least two different ways now, sort of initially hidden ways 0:21:54.440 --> 0:21:56.400 that you might not know about just by looking at them, 0:21:56.760 --> 0:22:00.879 that some hermit crabs have evolved the same at aptations 0:22:01.000 --> 0:22:05.239 to shell life as the snails that originally made the 0:22:05.280 --> 0:22:08.760 shells they inhabit. So the first example we talked about 0:22:08.800 --> 0:22:13.480 was hermit crabs evolving asymmetrically sized claws, so they can 0:22:13.600 --> 0:22:18.399 use one claw as an operculum, which means an aperture 0:22:18.480 --> 0:22:21.680 covering a door to close a hole, and they use 0:22:21.760 --> 0:22:24.440 that larger claw to close the whole of the shell 0:22:24.520 --> 0:22:28.040 when they retreat inside. And the parallel with the snails 0:22:28.240 --> 0:22:31.000 is that many snails have the same adaptation. It's part 0:22:31.040 --> 0:22:34.280 of their bodies. They often have a hard plate called 0:22:34.359 --> 0:22:38.199 an operculum that closes over the shell aperture when the 0:22:38.240 --> 0:22:40.879 snail goes inside to hide. So like the hermit crabs 0:22:40.920 --> 0:22:45.960 evolutionarily recreated that function with their claws. And now we 0:22:46.040 --> 0:22:50.080 see examples of both snails and later hermit crabs that 0:22:50.240 --> 0:22:54.000 inhabit the same types of snail shells, taking a calcified 0:22:54.040 --> 0:22:57.439 shell of a fixed size and then dissolving some of 0:22:57.480 --> 0:23:00.600 the interior surfaces of that shell to make more room 0:23:00.760 --> 0:23:02.320 or make it better suit their needs. 0:23:02.920 --> 0:23:03.800 Yeah, it's amazing. 0:23:04.119 --> 0:23:07.800 But anyway, so after this whole narratid digression, coming back 0:23:07.840 --> 0:23:10.199 to Gould and his essay, so he says that he 0:23:10.240 --> 0:23:13.320 saw all these hermit crabs in Bermuda trying to survive 0:23:13.400 --> 0:23:16.359 by cramming their big old bodies into the shells of 0:23:16.440 --> 0:23:20.240 narrotied snails which were way too small for them. But 0:23:20.359 --> 0:23:22.480 then he says, one day he came across one of 0:23:22.520 --> 0:23:25.440 these larger hermit crabs with a better fitting shell, a 0:23:25.520 --> 0:23:29.240 much bigger shell. And this was not from a narrotied snail, 0:23:29.280 --> 0:23:31.840 but in this case from a whlk. It was a 0:23:31.840 --> 0:23:37.280 species called Sitarium pica, commonly known as the West Indian 0:23:37.320 --> 0:23:41.520