1 00:00:01,800 --> 00:00:04,320 Speaker 1: Welcome to brain Stuff, a production of I Heart Radio. 2 00:00:06,720 --> 00:00:10,760 Speaker 1: Hey brain Stuff, Lauren Boga bom Here. If you or 3 00:00:10,840 --> 00:00:13,200 Speaker 1: a friend had a hermit crab when you were a kid, 4 00:00:13,480 --> 00:00:16,360 Speaker 1: or if you have one now, you're familiar with how 5 00:00:16,400 --> 00:00:19,279 Speaker 1: they'll make a home in a snail shell in the 6 00:00:19,320 --> 00:00:23,079 Speaker 1: wild or a terrarium. They'll squeeze into an empty shell 7 00:00:23,200 --> 00:00:25,640 Speaker 1: that's just the right size for them to carry around 8 00:00:25,680 --> 00:00:29,520 Speaker 1: as mobile protection. They're soft bellies, sheltered and their legs 9 00:00:29,600 --> 00:00:32,680 Speaker 1: free for crawling. Most of the ones we keep as 10 00:00:32,720 --> 00:00:35,120 Speaker 1: pets in the US are just an inch or too long, 11 00:00:35,360 --> 00:00:39,960 Speaker 1: up to about five centimeters. Okay, now picture that little buddy, 12 00:00:40,120 --> 00:00:43,559 Speaker 1: but twenty to thirty times larger and having grown just 13 00:00:43,840 --> 00:00:46,680 Speaker 1: enough offenses that they no longer need to carry a 14 00:00:46,800 --> 00:00:50,320 Speaker 1: defensive shell. And that's what you're looking at when you 15 00:00:50,360 --> 00:00:54,160 Speaker 1: consider the coconut crab, a close cousin to the pet 16 00:00:54,160 --> 00:00:56,960 Speaker 1: hermit crabs that we keep. The coconut crab is native 17 00:00:56,960 --> 00:00:59,760 Speaker 1: to the islands in the Pacific and Indian Oceans, and 18 00:00:59,760 --> 00:01:03,800 Speaker 1: they're the world's biggest land dwelling arthropods. They can weigh 19 00:01:03,880 --> 00:01:06,360 Speaker 1: up to nine pounds that's about four kilos with a 20 00:01:06,440 --> 00:01:10,680 Speaker 1: leg span of around three ft or one meter. This 21 00:01:10,800 --> 00:01:12,840 Speaker 1: is only about the third of the leg span of 22 00:01:12,840 --> 00:01:16,440 Speaker 1: the Japanese spider crab, which is the biggest arthur pod period, 23 00:01:16,880 --> 00:01:19,160 Speaker 1: but as it's an ocean dweller, it has less of 24 00:01:19,160 --> 00:01:22,280 Speaker 1: a chance to startle us with its sheer size. Most 25 00:01:22,319 --> 00:01:26,679 Speaker 1: coconut crabs are longer than most dogs, and coconut crabs 26 00:01:26,680 --> 00:01:30,319 Speaker 1: have been known to eat kittens, rats, chickens, and each other. 27 00:01:31,080 --> 00:01:33,560 Speaker 1: They've even been proposed as a possible culprit in the 28 00:01:33,600 --> 00:01:36,960 Speaker 1: disappearance of the body of Amelia Earhart, as we've discussed 29 00:01:36,959 --> 00:01:40,960 Speaker 1: before on the show. For the article this episode is 30 00:01:40,959 --> 00:01:44,240 Speaker 1: based on How Stuff Works, spoke with Shinichio Oka, chief 31 00:01:44,280 --> 00:01:47,680 Speaker 1: research scientist at the Okinawa Choshima Research Center in Japan. 32 00:01:48,560 --> 00:01:52,240 Speaker 1: He said, the coconut crabs have no seashell as protection 33 00:01:52,320 --> 00:01:55,520 Speaker 1: from enemies, so they have powerful claws and a large 34 00:01:55,520 --> 00:01:59,360 Speaker 1: body to protect themselves. In addition, they're mighty claws. Let 35 00:01:59,360 --> 00:02:03,520 Speaker 1: the monopoly is the terrestrial hard foods, including coconuts, which 36 00:02:03,560 --> 00:02:08,799 Speaker 1: other animals are unable to get into. So exactly how 37 00:02:08,880 --> 00:02:12,880 Speaker 1: strong are the claws of a coconut crab? OCAs said, 38 00:02:13,360 --> 00:02:16,080 Speaker 1: we could find that coconut crabs can generate the pinching 39 00:02:16,120 --> 00:02:19,720 Speaker 1: force of ninety times of their body weight. The calculated 40 00:02:19,720 --> 00:02:22,600 Speaker 1: pinching force of the largest coconut crab is almost equal 41 00:02:22,639 --> 00:02:27,520 Speaker 1: to the bite force of the adult lions. So these 42 00:02:27,560 --> 00:02:32,400 Speaker 1: overgrown coconuts smashing kitten eating crustaceans are nightmare versions of 43 00:02:32,440 --> 00:02:35,400 Speaker 1: the petite and mildly pinchet hermit crabs that we know. 44 00:02:36,160 --> 00:02:38,840 Speaker 1: But they actually do spend some of their life cycle 45 00:02:38,919 --> 00:02:43,480 Speaker 1: in the same manner as their dainty your cousins. Coconut 46 00:02:43,520 --> 00:02:45,960 Speaker 1: crabs spend most of their lives on land, but they 47 00:02:45,960 --> 00:02:49,880 Speaker 1: start out in the sea. A female coconut crab deposits larva, 48 00:02:50,000 --> 00:02:52,400 Speaker 1: which she's been carrying around in her abdomen since they 49 00:02:52,400 --> 00:02:55,680 Speaker 1: were just fertilized eggs, into the ocean, and the babies 50 00:02:55,760 --> 00:02:57,800 Speaker 1: float around in the currents for a month or so 51 00:02:58,240 --> 00:03:01,040 Speaker 1: eating other plankton, before gay enough body weight that they 52 00:03:01,120 --> 00:03:04,320 Speaker 1: dropped the sea floor and find nice cozy snail shells 53 00:03:04,320 --> 00:03:08,400 Speaker 1: to move into. Just like your childhood hermit crab friend, 54 00:03:08,680 --> 00:03:11,240 Speaker 1: the young coconut crabs move in and out of shells 55 00:03:11,280 --> 00:03:14,120 Speaker 1: as they bulk up and get used to living on land, 56 00:03:14,840 --> 00:03:17,680 Speaker 1: and sometimes a juvenile coconut crab will use a coconut 57 00:03:17,760 --> 00:03:20,840 Speaker 1: husk or empty seashell is armor until its own shell 58 00:03:20,960 --> 00:03:25,480 Speaker 1: gets harder. After about a year, the teens of the 59 00:03:25,480 --> 00:03:28,520 Speaker 1: species eventually find that there are no shells left on 60 00:03:28,520 --> 00:03:31,440 Speaker 1: the beach large enough to accommodate their bulk, and so 61 00:03:31,520 --> 00:03:34,800 Speaker 1: they move out altogether. From here on out, they live 62 00:03:34,840 --> 00:03:37,280 Speaker 1: the rest of their lives out of the water. Adult 63 00:03:37,280 --> 00:03:40,920 Speaker 1: coconut crabs can't swim and will drown if totally submerged. 64 00:03:42,720 --> 00:03:46,720 Speaker 1: Adult coconut crabs bodies have kelcium based exo skeletons, which 65 00:03:46,840 --> 00:03:49,560 Speaker 1: hard enough more than hermit crabs do once they mature, 66 00:03:50,080 --> 00:03:52,800 Speaker 1: so they're free to grow as monstrous size as they 67 00:03:52,800 --> 00:03:56,680 Speaker 1: can manage. Every few months, coconut crabs molt their too 68 00:03:56,720 --> 00:03:59,720 Speaker 1: tight exo skeletons and then grow a larger one they 69 00:04:00,120 --> 00:04:03,080 Speaker 1: the old one after they've shed it. Coconut crabs will 70 00:04:03,080 --> 00:04:06,360 Speaker 1: eat almost anything, all kinds of fruit, plant matter, dead 71 00:04:06,400 --> 00:04:09,400 Speaker 1: animals they find lying around, food you've left lying around 72 00:04:09,520 --> 00:04:13,320 Speaker 1: other crab species, or even their own friends. Actually, coconut 73 00:04:13,320 --> 00:04:17,320 Speaker 1: crabs don't really have friends. They're pretty solitary. They have 74 00:04:17,480 --> 00:04:20,160 Speaker 1: an excellent sense of smell, which makes them great at 75 00:04:20,200 --> 00:04:25,200 Speaker 1: finding rotting carcasses and anything else potentially edible. Coconut crabs 76 00:04:25,200 --> 00:04:28,240 Speaker 1: are also sometimes called robber crabs because they've been known 77 00:04:28,279 --> 00:04:31,440 Speaker 1: to steal items like silverware that has even the faint 78 00:04:31,480 --> 00:04:36,560 Speaker 1: odor of food about it. But their most important source 79 00:04:36,600 --> 00:04:40,400 Speaker 1: of nutrients is coconuts. Because coconuts seem to be what 80 00:04:40,440 --> 00:04:44,480 Speaker 1: allows them to achieve the gigantism they're known for. Coconut 81 00:04:44,520 --> 00:04:47,240 Speaker 1: crabs will climb trees to get at coconuts and use 82 00:04:47,279 --> 00:04:51,640 Speaker 1: their pinchers to open them. Study found that the coconut 83 00:04:51,720 --> 00:04:54,599 Speaker 1: crabs that have access to coconuts are likely to have 84 00:04:54,720 --> 00:04:59,400 Speaker 1: around double the mass of those living in coconut free environments. 85 00:04:59,440 --> 00:05:02,720 Speaker 1: So a coconut crab is lucky enough to have coconuts around, 86 00:05:02,960 --> 00:05:05,640 Speaker 1: and if it's strong enough to pan opener its way 87 00:05:05,640 --> 00:05:08,560 Speaker 1: into a coconut, it's able to grow a lot bigger 88 00:05:08,839 --> 00:05:12,719 Speaker 1: and then access even more coconuts the size ceiling gets 89 00:05:12,760 --> 00:05:17,960 Speaker 1: a whole lot higher. But coconut crabs are not invulnerable, 90 00:05:18,680 --> 00:05:21,880 Speaker 1: their numbers seem to be declining, probably because the islands 91 00:05:21,920 --> 00:05:23,720 Speaker 1: that they live on aren't what they used to be. 92 00:05:24,320 --> 00:05:28,240 Speaker 1: Introduced species like dogs, pigs, and humans eat the adults, 93 00:05:28,480 --> 00:05:32,279 Speaker 1: and invasive rats gobble up the smaller, more vulnerable babies. 94 00:05:33,080 --> 00:05:35,960 Speaker 1: They're extremely slow growing and can live to be about 95 00:05:36,000 --> 00:05:39,719 Speaker 1: fifty years old. Coconut crabs have been listed as data 96 00:05:39,760 --> 00:05:43,719 Speaker 1: deficient by the International Union for Conservation of Nature, meaning 97 00:05:43,920 --> 00:05:46,960 Speaker 1: nobody really knows enough about these animals to understand their 98 00:05:47,000 --> 00:05:50,760 Speaker 1: conservation needs. Although it's likely that they're not doing well, 99 00:05:50,880 --> 00:05:54,839 Speaker 1: their status was last assessed in so more research is 100 00:05:54,880 --> 00:06:03,600 Speaker 1: needed to understand where coconut crabs stand m Today's episode 101 00:06:03,680 --> 00:06:05,800 Speaker 1: is based on the article called the coconut Crab, a 102 00:06:05,839 --> 00:06:08,679 Speaker 1: crustacean on steroids on house toff works dot com, written 103 00:06:08,680 --> 00:06:11,440 Speaker 1: by Jesselyn Shields. Brain Stuff is production of I Heart 104 00:06:11,480 --> 00:06:13,800 Speaker 1: Radio in partnership with how Stuffwork dot Com, and it's 105 00:06:13,839 --> 00:06:17,119 Speaker 1: produced by Tyler Clang. Four more podcasts my heart Radio 106 00:06:17,320 --> 00:06:20,000 Speaker 1: visit the i heart Radio app, Apple Podcasts, or wherever 107 00:06:20,040 --> 00:06:21,440 Speaker 1: you listen to your favorite shows.