1 00:00:05,720 --> 00:00:07,480 Speaker 1: Hey, you welcome to Stuff to blow your mind. My 2 00:00:07,560 --> 00:00:10,320 Speaker 1: name is Robert Lamb and I'm Joe McCormick, and it's Saturday. 3 00:00:10,360 --> 00:00:13,240 Speaker 1: Time to go into the Old Vault for an episode 4 00:00:13,320 --> 00:00:18,840 Speaker 1: from December of This published December, and this was part 5 00:00:18,920 --> 00:00:22,639 Speaker 1: one of our two part episode about the Christmas Island 6 00:00:22,720 --> 00:00:26,680 Speaker 1: Crabs or Christmas Island Wildlife more generally. Yeah, I remember 7 00:00:26,760 --> 00:00:30,160 Speaker 1: the original title for this was Christmas Island Crabs Part 8 00:00:30,240 --> 00:00:34,519 Speaker 1: one colon Crabs rule everything around me um and and 9 00:00:34,560 --> 00:00:37,080 Speaker 1: then the next one, Part two also originally had a 10 00:00:37,080 --> 00:00:40,519 Speaker 1: Wu Tang themed title as well. But yeah, this was 11 00:00:40,560 --> 00:00:43,400 Speaker 1: just a really nothing to do with Christmas itself for 12 00:00:43,440 --> 00:00:45,120 Speaker 1: the most part. I think we maybe we sang some 13 00:00:45,240 --> 00:00:47,720 Speaker 1: Christmas songs. I think you made one up. I don't 14 00:00:47,760 --> 00:00:50,240 Speaker 1: remember which part it was in, But for the most part, 15 00:00:50,479 --> 00:00:54,560 Speaker 1: this is all about crabs and only marginally about Christmas. 16 00:00:54,600 --> 00:00:57,040 Speaker 1: It's like life, life is also all about crabs and 17 00:00:57,080 --> 00:01:00,680 Speaker 1: marginally about Christmas. Okay, yeah, I think I think that's 18 00:01:00,720 --> 00:01:07,080 Speaker 1: that's solid. All right, let's let's dive right in. It 19 00:01:07,319 --> 00:01:09,800 Speaker 1: was the Island of Christmas, and all across the land, 20 00:01:09,959 --> 00:01:13,000 Speaker 1: the red crabs were flowing across Root Street and sand 21 00:01:13,640 --> 00:01:17,319 Speaker 1: like a red tide of scuttling, claw snapping doom. They 22 00:01:17,360 --> 00:01:20,960 Speaker 1: streamed through my front door and into my rooms. Meanwhile, 23 00:01:21,040 --> 00:01:25,240 Speaker 1: in the forests the giants they're crawled coconut crabs, hulking 24 00:01:25,280 --> 00:01:29,840 Speaker 1: monsters with claws. They hunted for carrion crab bird and 25 00:01:29,920 --> 00:01:39,200 Speaker 1: ratted and gobbled it up, rancid, sinew and fat. Welcome 26 00:01:39,200 --> 00:01:41,880 Speaker 1: to Stuff to Blow your Mind from how Stuff Works 27 00:01:41,880 --> 00:01:50,560 Speaker 1: dot Com. Hey, welcome to Stuff to Blow your Mind. 28 00:01:50,640 --> 00:01:53,200 Speaker 1: My name is Robert Lamb, and I'm Joe McCormick, and 29 00:01:53,240 --> 00:01:55,760 Speaker 1: getting in that holiday spirit, we're gonna be talking about 30 00:01:55,800 --> 00:02:00,160 Speaker 1: crab Horror. Yes, this is this pair of episode. I've 31 00:02:00,200 --> 00:02:03,200 Speaker 1: been looking forward to all year. This has been my 32 00:02:03,200 --> 00:02:06,080 Speaker 1: my goal. I forget when, but earlier in the year 33 00:02:06,400 --> 00:02:10,639 Speaker 1: I was reading about Christmas Island and the various creatures 34 00:02:10,680 --> 00:02:13,440 Speaker 1: that that call it home, and I realized, we have 35 00:02:13,560 --> 00:02:16,320 Speaker 1: to do this episode for Christmas. Even though this really 36 00:02:16,320 --> 00:02:20,160 Speaker 1: has nothing to do with Christmas, no, virtually nothing with Christmas, 37 00:02:20,160 --> 00:02:25,880 Speaker 1: though I do enjoy um like forcing decapods upon Christmas 38 00:02:26,240 --> 00:02:28,520 Speaker 1: and uh and and and at least in my mind, 39 00:02:28,560 --> 00:02:32,240 Speaker 1: allowing them to take over the holiday Decapods with bows 40 00:02:32,280 --> 00:02:35,040 Speaker 1: of all is it bows should have said clause of 41 00:02:35,080 --> 00:02:40,040 Speaker 1: the glory. Either way, I appreciate the holiday zeal. Now, 42 00:02:40,280 --> 00:02:43,680 Speaker 1: so we're going to be going to Crab Horror Island, 43 00:02:43,919 --> 00:02:46,880 Speaker 1: and there are many wonderful movies and maybe we'll save 44 00:02:46,919 --> 00:02:49,000 Speaker 1: it for next time to talk about our favorite Crab 45 00:02:49,040 --> 00:02:51,800 Speaker 1: Island movies. But the giant crab is one of my 46 00:02:51,800 --> 00:02:54,080 Speaker 1: favorite kind of movie monsters, and they've always got to 47 00:02:54,080 --> 00:02:56,960 Speaker 1: have their own island of terror, right right, and and 48 00:02:57,000 --> 00:02:59,959 Speaker 1: so in discussing Christmas Island and these two episodes, we're 49 00:03:00,000 --> 00:03:04,080 Speaker 1: going to talk about crabs or you know, decapods anyway 50 00:03:04,200 --> 00:03:10,080 Speaker 1: that are either enormous, uh, singularly and enormous or collectively enormous. 51 00:03:10,120 --> 00:03:11,960 Speaker 1: I think the first episode we're going to focus on 52 00:03:12,000 --> 00:03:15,200 Speaker 1: the collectively enormous, and the second episode will focus on 53 00:03:15,560 --> 00:03:20,160 Speaker 1: the decapods who are individually enormous. Now, this first episode 54 00:03:20,200 --> 00:03:23,800 Speaker 1: is going to focus on the Christmas Island Red Crab. Robert, 55 00:03:23,840 --> 00:03:26,560 Speaker 1: will you take me on a mystical adventure to crab 56 00:03:26,600 --> 00:03:31,000 Speaker 1: Horror Island. Yes, we're talking about Christmas Island so named. 57 00:03:31,040 --> 00:03:33,360 Speaker 1: It's in the Indian Ocean about three hundred and fifty 58 00:03:33,440 --> 00:03:36,680 Speaker 1: kilometers or two hundred and twenty miles south of Java 59 00:03:36,760 --> 00:03:41,560 Speaker 1: and Sumatra and around Uh let's see one thou fifty 60 00:03:41,600 --> 00:03:44,600 Speaker 1: kilometers are nine hundred and sixty miles northwest of the 61 00:03:44,640 --> 00:03:48,640 Speaker 1: closest point on the Australian Mainland. Technically part of Australia 62 00:03:48,680 --> 00:03:52,600 Speaker 1: though right it is an Australian external territory. It has 63 00:03:52,640 --> 00:03:55,480 Speaker 1: an area of a hundred square kilometers or fifty two 64 00:03:55,520 --> 00:03:58,320 Speaker 1: square miles, so not huge, No, not a big place 65 00:03:58,360 --> 00:04:01,600 Speaker 1: at all. It's a very old, though very old volcanic 66 00:04:01,720 --> 00:04:07,280 Speaker 1: seamount island. It was first visited by Europeans in sixty three. 67 00:04:07,760 --> 00:04:11,680 Speaker 1: Captain William Minors of the Royal Mary and English East 68 00:04:11,720 --> 00:04:14,640 Speaker 1: India Company vessel. He just named the island when he 69 00:04:14,680 --> 00:04:17,880 Speaker 1: sailed past it on Christmas Day of that year. That's 70 00:04:17,920 --> 00:04:21,320 Speaker 1: that's the only Christmas high end there he didn't find, 71 00:04:21,760 --> 00:04:25,359 Speaker 1: you know, and naturally occurring Christmas tree there. Uh, there's 72 00:04:25,360 --> 00:04:28,800 Speaker 1: no wasn't where the elf workshop was exactly. There's there's 73 00:04:28,839 --> 00:04:31,360 Speaker 1: nothing else about it except it was Christmas Day when 74 00:04:31,360 --> 00:04:32,960 Speaker 1: he found it. It could have easily it could have 75 00:04:33,000 --> 00:04:36,440 Speaker 1: easily turned out to be Christmas Eve Island, or Boxing 76 00:04:36,520 --> 00:04:39,520 Speaker 1: Day Island or Halloween Island. That would perhaps be a 77 00:04:39,560 --> 00:04:44,160 Speaker 1: little more appropriate, yea. So that one of the cool 78 00:04:44,279 --> 00:04:47,160 Speaker 1: things about this place is that when when they were 79 00:04:47,200 --> 00:04:49,600 Speaker 1: able to take a closer look at it, they realized 80 00:04:49,640 --> 00:04:52,560 Speaker 1: that it was uninhabited at least by humans. So it's 81 00:04:52,560 --> 00:04:56,440 Speaker 1: obvious that what makes this island unique is not anything 82 00:04:56,480 --> 00:04:59,880 Speaker 1: about the indigenous culture or anything, since it was apparently 83 00:05:00,040 --> 00:05:04,000 Speaker 1: uninhabited originally, but it was not uninhabited by wildlife. As 84 00:05:04,000 --> 00:05:07,320 Speaker 1: we've made clear, the wildlife there was of a terrific 85 00:05:07,400 --> 00:05:10,200 Speaker 1: scuttling variety, oh correct. And one of the really cool 86 00:05:10,200 --> 00:05:12,880 Speaker 1: things about the scuttling life on Christmas Island it is 87 00:05:12,880 --> 00:05:14,960 Speaker 1: that so much of it is on Christmas Island. We're 88 00:05:14,960 --> 00:05:18,400 Speaker 1: talking about land crabs, crabs that need only returned to 89 00:05:18,440 --> 00:05:21,760 Speaker 1: the water to mate, but mostly live on land. And 90 00:05:21,800 --> 00:05:23,800 Speaker 1: you'll find these elsewhere. To be sure, this is not 91 00:05:23,880 --> 00:05:27,840 Speaker 1: the only place land crabs can be found, uh, And 92 00:05:27,920 --> 00:05:31,240 Speaker 1: we're we're talking about both true crabs as well as 93 00:05:31,279 --> 00:05:35,279 Speaker 1: hermit crabs here. Hermit crabs are decapods, but not true crabs. 94 00:05:36,279 --> 00:05:38,840 Speaker 1: But forgive us as we as we talk about them 95 00:05:38,839 --> 00:05:40,720 Speaker 1: in these episodes, I will probably end up calling them 96 00:05:40,720 --> 00:05:44,520 Speaker 1: both crabs in the unofficial sense. The Christmas Island is 97 00:05:44,560 --> 00:05:47,760 Speaker 1: home to more land crabs than anywhere else on Earth. 98 00:05:47,800 --> 00:05:52,000 Speaker 1: We're talking more than twenty terrestrial and semi terrestrial crabs species, 99 00:05:52,240 --> 00:05:54,880 Speaker 1: plus a hundred and sixties species or thereabouts in the 100 00:05:54,920 --> 00:05:58,360 Speaker 1: reefs and shallows around the island. Yeah, so Robert tell 101 00:05:58,400 --> 00:06:01,440 Speaker 1: me a little bit about crabs. Well, just to refresh everybody, 102 00:06:01,480 --> 00:06:04,800 Speaker 1: crabs are crustaceans. But we should be clear that again, 103 00:06:04,839 --> 00:06:09,080 Speaker 1: there are true crabs of the decapoda soap order bracci ura, 104 00:06:09,200 --> 00:06:13,400 Speaker 1: which means small tail um, which references their smaller abdomen. 105 00:06:13,920 --> 00:06:17,320 Speaker 1: And then there are the ano mora or mixed tail crabs, 106 00:06:17,360 --> 00:06:20,280 Speaker 1: which included hermits and as we'll discuss later in the 107 00:06:20,320 --> 00:06:24,560 Speaker 1: second episode, robber crabs. But still again we're often going 108 00:06:24,600 --> 00:06:27,760 Speaker 1: to refer to them both as crabs in the unofficial sense. 109 00:06:28,440 --> 00:06:30,560 Speaker 1: And these were these are ancient creatures. These were the 110 00:06:30,600 --> 00:06:36,040 Speaker 1: first animals to develop true legs, none of those false legs. Yeah, 111 00:06:36,080 --> 00:06:38,159 Speaker 1: I mean, we we've talked about crabs in the show before. 112 00:06:38,200 --> 00:06:40,640 Speaker 1: I think back to our episode about Carl Sagan and 113 00:06:40,640 --> 00:06:44,600 Speaker 1: the Samurai crabs. So so hopefully everyone is is on 114 00:06:44,640 --> 00:06:48,680 Speaker 1: board for two more episodes of crab based content. But 115 00:06:48,800 --> 00:06:52,719 Speaker 1: so it's not just the varieties of crab and crab 116 00:06:52,800 --> 00:06:56,040 Speaker 1: like creatures that live on Christmas Island that make it 117 00:06:56,200 --> 00:07:00,120 Speaker 1: Crab Island Earth, Uh, it is is the number are 118 00:07:00,360 --> 00:07:04,000 Speaker 1: of a particular species of crab there, the Christmas Island 119 00:07:04,040 --> 00:07:09,440 Speaker 1: red crab, where there are supposedly tens of millions of 120 00:07:09,520 --> 00:07:11,760 Speaker 1: these crabs on the island. And this is not a 121 00:07:11,760 --> 00:07:14,920 Speaker 1: big island. Remember it's a hundred thirty five square kilometers, right, 122 00:07:15,000 --> 00:07:17,040 Speaker 1: a small island. And yet yeah, I've seen the figures 123 00:07:17,040 --> 00:07:20,480 Speaker 1: of like fifty million of these creatures living, living in 124 00:07:20,520 --> 00:07:23,480 Speaker 1: the forest, living, you know, pretty much all over the island. 125 00:07:23,520 --> 00:07:26,440 Speaker 1: And that's a reduced number. I remember we watched a 126 00:07:26,520 --> 00:07:29,560 Speaker 1: documentary about the island from the nineteen eighties that suggested 127 00:07:29,680 --> 00:07:31,440 Speaker 1: the time it was believed that there were over a 128 00:07:31,520 --> 00:07:34,240 Speaker 1: hundred million of the crabs. They're right. That was a 129 00:07:34,520 --> 00:07:39,280 Speaker 1: nine eight eight David Attenborough narrated special titled Kingdom of 130 00:07:39,320 --> 00:07:41,680 Speaker 1: the Crabs. Great title, and that's a great one to 131 00:07:41,680 --> 00:07:43,760 Speaker 1: watch if you get a chance, because it really shows 132 00:07:43,800 --> 00:07:48,840 Speaker 1: off what makes this island visually astounding. But it's the 133 00:07:48,880 --> 00:07:51,400 Speaker 1: sheer numbers of the crabs, and the Christmas Island red 134 00:07:51,440 --> 00:07:55,560 Speaker 1: crab is pretty much found only on Christmas Island. Yeah, 135 00:07:55,600 --> 00:07:58,560 Speaker 1: I think maybe on another nearby island or island group, 136 00:07:58,560 --> 00:08:01,080 Speaker 1: but they're not found like all over the place. So 137 00:08:01,240 --> 00:08:03,080 Speaker 1: I do want to come back to the human history 138 00:08:03,160 --> 00:08:06,600 Speaker 1: for a little bit before we explore the Red uh 139 00:08:07,240 --> 00:08:10,120 Speaker 1: Crab in depth. So the most you know, essential thing 140 00:08:10,160 --> 00:08:12,440 Speaker 1: about human history of Christmas Island is that for the 141 00:08:12,480 --> 00:08:14,960 Speaker 1: longest there seems to have been none. It is a 142 00:08:15,000 --> 00:08:19,520 Speaker 1: geographically isolated place now from everything I've read so far, 143 00:08:19,720 --> 00:08:23,040 Speaker 1: and it's always possible on missing something, but there's no 144 00:08:23,200 --> 00:08:26,960 Speaker 1: evidence that humans ever visited the place before the seventeenth century. 145 00:08:27,200 --> 00:08:31,680 Speaker 1: See this, despite Java being again only two miles away. 146 00:08:32,080 --> 00:08:34,760 Speaker 1: It's a short enough distance for modern humans anyway that 147 00:08:34,920 --> 00:08:38,480 Speaker 1: boats of asylum seekers frequently make it their point of 148 00:08:38,520 --> 00:08:42,720 Speaker 1: destination in reaching Australia, because again it's an Australian external territory, 149 00:08:42,800 --> 00:08:45,160 Speaker 1: So if you reach Christmas Island, you are, you know, 150 00:08:45,200 --> 00:08:49,200 Speaker 1: in a legal sense, in Australia. However, it's also worth 151 00:08:49,200 --> 00:08:52,520 Speaker 1: pointing out that the seas can be deadly surrounding Christmas 152 00:08:52,520 --> 00:08:55,600 Speaker 1: Island and their stories out there boats of asylum seekers 153 00:08:55,679 --> 00:08:58,520 Speaker 1: breaking on the Rocky coast with lethal results. I think 154 00:08:58,520 --> 00:09:01,440 Speaker 1: I've read about this in cases the early visitors to 155 00:09:01,480 --> 00:09:03,640 Speaker 1: the island also that you know, it was kind of 156 00:09:03,720 --> 00:09:07,160 Speaker 1: dangerous to land there. And for example, there was one 157 00:09:07,160 --> 00:09:09,400 Speaker 1: case where I read that a crew was driven to 158 00:09:09,559 --> 00:09:11,840 Speaker 1: land there because there was scurvy on the ship, and 159 00:09:11,880 --> 00:09:14,360 Speaker 1: it was only because the disease had gotten so bad 160 00:09:14,440 --> 00:09:17,079 Speaker 1: that they risked trying to land. Yeah, that's sort of 161 00:09:17,120 --> 00:09:20,640 Speaker 1: the typical story book reasons for landing on an uninhabited 162 00:09:20,640 --> 00:09:24,240 Speaker 1: island with a strange crab population. Yeah, but out of 163 00:09:24,280 --> 00:09:27,480 Speaker 1: the scurvy pan into the crabs. Yeah, and you know it, 164 00:09:27,600 --> 00:09:29,640 Speaker 1: but but it is. It is weird to think about 165 00:09:29,679 --> 00:09:33,679 Speaker 1: places like this, places where where humans just didn't take 166 00:09:33,760 --> 00:09:36,360 Speaker 1: up residents. And of course you have to, of course 167 00:09:36,640 --> 00:09:41,520 Speaker 1: realize that moving to an isolated island is a difficult proposition, 168 00:09:41,880 --> 00:09:43,360 Speaker 1: like you've really got to have a reason to go 169 00:09:43,440 --> 00:09:46,080 Speaker 1: there and a reason to stay there, and a way 170 00:09:46,120 --> 00:09:51,280 Speaker 1: to um to to safely arrived there as well. But still, 171 00:09:51,320 --> 00:09:53,439 Speaker 1: you know, it's enough to make one wonder. For instance, 172 00:09:53,520 --> 00:09:56,480 Speaker 1: Homo erectus, or a Java man, lived on the island 173 00:09:56,480 --> 00:10:00,640 Speaker 1: of Java relatively close by one point seven years ago. 174 00:10:01,120 --> 00:10:06,480 Speaker 1: Humans practiced agriculture. They're on Java as early as b C. 175 00:10:07,320 --> 00:10:10,280 Speaker 1: Java was known to traders and other powers. The Kingdom 176 00:10:10,400 --> 00:10:13,199 Speaker 1: of Mataram ruled there until they lost power to the 177 00:10:13,240 --> 00:10:16,600 Speaker 1: Dutch East India Company in seventeen forty nine and became 178 00:10:16,640 --> 00:10:20,440 Speaker 1: a vassal state of the Company UM, a statement that 179 00:10:20,520 --> 00:10:24,000 Speaker 1: I think really drives home the power of the East 180 00:10:24,040 --> 00:10:26,839 Speaker 1: India Company UM, the idea that you would have a 181 00:10:27,400 --> 00:10:31,360 Speaker 1: vassal state to a corporation. Yeah, but that's a Jova. 182 00:10:31,400 --> 00:10:33,680 Speaker 1: My point is that I just find it so enthralling 183 00:10:33,760 --> 00:10:36,440 Speaker 1: that this island remained either free of human contact for 184 00:10:36,480 --> 00:10:39,640 Speaker 1: so long or only encountered minimal influence. You know. It's 185 00:10:39,679 --> 00:10:42,720 Speaker 1: I guess it's possible that it's at some point somebody 186 00:10:42,760 --> 00:10:46,920 Speaker 1: wound up there by purpose or accident and they didn't stay, 187 00:10:47,160 --> 00:10:49,960 Speaker 1: didn't stay long enough to leave a footprint, you know. 188 00:10:50,160 --> 00:10:53,520 Speaker 1: Galapagos Islands or another example of this, though there there 189 00:10:53,520 --> 00:10:57,160 Speaker 1: have been at least disputed claims of Inca artifacts found 190 00:10:57,320 --> 00:11:00,160 Speaker 1: on the Galapagos Islands, perhaps due to Inca sailors being 191 00:11:00,200 --> 00:11:04,120 Speaker 1: blown off course. The Statials in the Indian Ocean are 192 00:11:04,160 --> 00:11:06,679 Speaker 1: another example of islands that were uninhabited through most of 193 00:11:06,720 --> 00:11:09,800 Speaker 1: recorded history, though they may have been visited by early 194 00:11:09,840 --> 00:11:12,200 Speaker 1: seafares as well, depending on who you talked to. But 195 00:11:12,240 --> 00:11:14,920 Speaker 1: with Christmas Island I found no such thing, and not 196 00:11:15,000 --> 00:11:18,920 Speaker 1: even a crackpot theory. So it really does seem as 197 00:11:18,920 --> 00:11:21,679 Speaker 1: if humans, not even the Vikings, went there the by 198 00:11:21,720 --> 00:11:23,840 Speaker 1: no Vikings or anything. So it really does seem that 199 00:11:23,840 --> 00:11:27,319 Speaker 1: nobody visited it until the seventeenth century, with the earliest 200 00:11:27,679 --> 00:11:31,520 Speaker 1: sighting I think having occurred in sixteen fifteen. Now after that, 201 00:11:31,600 --> 00:11:35,720 Speaker 1: of course, it actually did become an economically significant island 202 00:11:35,800 --> 00:11:38,880 Speaker 1: because of mineral deposits discovered there. That's right. It was 203 00:11:38,920 --> 00:11:43,600 Speaker 1: explored by British naturalist John Murray, and this was eighteen 204 00:11:43,640 --> 00:11:47,439 Speaker 1: seventy two. He discovered that there were phosphate deposits on 205 00:11:47,480 --> 00:11:50,080 Speaker 1: the island, which would play a key role in the 206 00:11:50,080 --> 00:11:55,120 Speaker 1: island's future. Exportation of phosphate begin in eighteen by the 207 00:11:55,240 --> 00:11:58,680 Speaker 1: Christmas Island Phosphate Company, and this activity led to the 208 00:11:58,679 --> 00:12:01,880 Speaker 1: loss of twenty of the island's rainforest area. Yeah, Now, 209 00:12:01,960 --> 00:12:04,800 Speaker 1: phosphate was important in the late eighteen hundreds because it 210 00:12:04,880 --> 00:12:08,360 Speaker 1: had been discovered by that time that phosphate, when treated 211 00:12:08,360 --> 00:12:11,360 Speaker 1: with sulfuric acid, could be used as an ingredient in 212 00:12:11,480 --> 00:12:15,200 Speaker 1: plant food, and of course synthetic fertilizers became very important 213 00:12:15,200 --> 00:12:18,360 Speaker 1: in the development of commercial agriculture at scale, and so 214 00:12:18,400 --> 00:12:21,280 Speaker 1: now there was a reason and economic reason for people 215 00:12:21,360 --> 00:12:25,679 Speaker 1: to not only go to Christmas Island but to work there, 216 00:12:26,200 --> 00:12:30,000 Speaker 1: and so settlement began in the eighteen eighties. Uh later on, 217 00:12:30,440 --> 00:12:32,920 Speaker 1: during the Second World War, there was a Japanese occupation 218 00:12:32,960 --> 00:12:37,040 Speaker 1: of the island from ninety five, and in the post 219 00:12:37,040 --> 00:12:40,160 Speaker 1: war period it was administered by Singapore, which was then 220 00:12:40,200 --> 00:12:43,480 Speaker 1: a British colony, and then Australia purchased the island for 221 00:12:43,520 --> 00:12:47,120 Speaker 1: two point nine million pounds on January one, nineteen fifty 222 00:12:47,160 --> 00:12:50,800 Speaker 1: eight day that's known as Territory Day on Christmas Island. 223 00:12:52,120 --> 00:12:55,400 Speaker 1: Today it has around I've read two thousand full time 224 00:12:55,880 --> 00:13:00,200 Speaker 1: human residents and the ethnic makeup is mostly Chinese and 225 00:13:00,320 --> 00:13:03,560 Speaker 1: melee Um originally brought in for labor. Now a big 226 00:13:03,600 --> 00:13:07,360 Speaker 1: portion of the land of the island today is basically 227 00:13:07,400 --> 00:13:11,760 Speaker 1: a national park. It's like a big wildlife preservation area. Yeah, 228 00:13:11,800 --> 00:13:15,040 Speaker 1: two thirds of its landmasters are national park now and 229 00:13:15,080 --> 00:13:17,559 Speaker 1: a big part of the wildlife significance here is the 230 00:13:17,640 --> 00:13:20,240 Speaker 1: Christmas Island red crabs. So I guess we should dive 231 00:13:20,400 --> 00:13:23,280 Speaker 1: headfirst into a puddle of crabs after we come back 232 00:13:23,320 --> 00:13:28,320 Speaker 1: from a break. Thank thank alright, we're back, So it 233 00:13:28,440 --> 00:13:31,120 Speaker 1: is time to dive into a pit of crabs. The 234 00:13:31,240 --> 00:13:36,160 Speaker 1: Christmas Island red crab or get Karkoitia natalis. And these 235 00:13:36,160 --> 00:13:39,200 Speaker 1: are crabs that live, as we mentioned earlier, primarily not 236 00:13:39,360 --> 00:13:42,440 Speaker 1: in the ocean, not even on the shoreline, but in 237 00:13:42,440 --> 00:13:45,719 Speaker 1: inland forests. So if you picture Christmas Island, it's sort 238 00:13:45,760 --> 00:13:50,200 Speaker 1: of a terraced rainforest. It's a you know, a volcanic island. 239 00:13:50,480 --> 00:13:53,840 Speaker 1: It's got some steep slopes that go up onto rainforest 240 00:13:54,160 --> 00:13:57,040 Speaker 1: covered terraces, and the crabs go all the way up 241 00:13:57,080 --> 00:14:00,520 Speaker 1: into the forests and make their burrows inland. Yeah, we're 242 00:14:00,520 --> 00:14:03,520 Speaker 1: talking against something like fifty million of these little land 243 00:14:03,559 --> 00:14:08,000 Speaker 1: dwellers uh in the forest chewing up leaf litter, and 244 00:14:08,040 --> 00:14:11,040 Speaker 1: here on Christmas Island they are the chief decay agents 245 00:14:11,080 --> 00:14:14,240 Speaker 1: for that leaf litter. I've seen estimates of something like 246 00:14:14,320 --> 00:14:18,040 Speaker 1: four thousand crabs per acre to keep the leaf litter down. Yes, 247 00:14:18,120 --> 00:14:21,160 Speaker 1: and they primarily feed on plant matter, Like you say, 248 00:14:21,200 --> 00:14:23,320 Speaker 1: so that is going to be leaf litter. It's also 249 00:14:23,400 --> 00:14:28,120 Speaker 1: things like fallen fruits and seeds, flowers, et cetera. But 250 00:14:28,440 --> 00:14:31,040 Speaker 1: they're also crabs after all, so you might not be 251 00:14:31,120 --> 00:14:35,400 Speaker 1: surprised to learn that they are opportunistic omnivores. My favorite 252 00:14:35,400 --> 00:14:38,400 Speaker 1: pairs of words. So if you get a little bit 253 00:14:38,440 --> 00:14:41,320 Speaker 1: of meat from say another dead red crab or something 254 00:14:41,360 --> 00:14:44,400 Speaker 1: like that presenting itself, this is a legitimate score, and 255 00:14:44,440 --> 00:14:47,160 Speaker 1: they will say, gentlemen, get that in my mouth parts. 256 00:14:47,200 --> 00:14:50,720 Speaker 1: It's time to masticate. But the crabs are important for 257 00:14:50,760 --> 00:14:53,600 Speaker 1: the maintenance of the ecosystem in multiple ways. So they 258 00:14:53,640 --> 00:14:56,680 Speaker 1: clear the forest floor of like leaf litter, but also 259 00:14:56,760 --> 00:15:01,800 Speaker 1: saplings and flowers other plants that would create dense underbrush, 260 00:15:01,880 --> 00:15:04,160 Speaker 1: and so they keep the forest floors clean and this 261 00:15:04,240 --> 00:15:08,800 Speaker 1: actually helps contribute to forest biodiversity. They also prevent the 262 00:15:08,880 --> 00:15:12,120 Speaker 1: soil from being packed too densely because of the burrows 263 00:15:12,160 --> 00:15:16,400 Speaker 1: they dig. They're like natural soil tillers. They turn the soil, 264 00:15:16,960 --> 00:15:21,080 Speaker 1: and this also helps contribute to forest biodiversity. But so 265 00:15:21,160 --> 00:15:23,360 Speaker 1: we might have a pretty good sense of what the 266 00:15:23,440 --> 00:15:26,080 Speaker 1: life of an ocean dwelling crab is like. What is 267 00:15:26,120 --> 00:15:28,920 Speaker 1: the life of a land crab Like crabs, as you 268 00:15:28,920 --> 00:15:31,720 Speaker 1: can imagine, in between chewing up things in their environment 269 00:15:31,720 --> 00:15:34,480 Speaker 1: and eating it, they have to stay moist and this means, 270 00:15:34,520 --> 00:15:36,760 Speaker 1: for one thing, staying out of the direct sun. So 271 00:15:36,800 --> 00:15:39,520 Speaker 1: the red crabs on Christmas Island like to stay in 272 00:15:39,520 --> 00:15:42,560 Speaker 1: the shady forests and they live in these dugout burrows 273 00:15:42,600 --> 00:15:45,160 Speaker 1: that they can hide from the sun in and they 274 00:15:45,160 --> 00:15:48,840 Speaker 1: have guilt chambers that have adapted for terrestrial life. They 275 00:15:48,840 --> 00:15:51,000 Speaker 1: have to keep them moist, and they also I love this, 276 00:15:51,080 --> 00:15:53,600 Speaker 1: they have to manually wet their eyes stalks. Yes, I 277 00:15:53,640 --> 00:15:55,400 Speaker 1: love this. It's pretty cool to watch if you can 278 00:15:55,440 --> 00:15:58,720 Speaker 1: find video of this. So their ice talks emerge from 279 00:15:58,800 --> 00:16:02,480 Speaker 1: little cups in their carapace, and they don't have eyelids 280 00:16:02,520 --> 00:16:04,760 Speaker 1: of course, by the way, it just try to imagine 281 00:16:04,800 --> 00:16:08,960 Speaker 1: life without eyelids kind of a terror. So they wet 282 00:16:09,080 --> 00:16:12,760 Speaker 1: and wash their eyes by filling their eye cups up 283 00:16:12,800 --> 00:16:16,520 Speaker 1: with drops of water and then dipping their eyestalks down 284 00:16:16,640 --> 00:16:20,480 Speaker 1: into the cups to rinse them off. Yeah, I think 285 00:16:20,520 --> 00:16:21,880 Speaker 1: this is This is one of the great things about 286 00:16:21,880 --> 00:16:25,880 Speaker 1: watching any crab close up, but especially with the Christmas 287 00:16:25,880 --> 00:16:29,160 Speaker 1: craps is those tiny, little sort of methodical movements that 288 00:16:29,200 --> 00:16:31,680 Speaker 1: you see take place with their mouth parts and their 289 00:16:31,760 --> 00:16:35,720 Speaker 1: their eyes stalks totally. Now, despite their life in the woods, 290 00:16:35,880 --> 00:16:38,240 Speaker 1: they still have to return to the sea to spawn, 291 00:16:38,680 --> 00:16:42,200 Speaker 1: and this results in a vast, scuttling migration that is 292 00:16:42,280 --> 00:16:45,520 Speaker 1: truly unlike anything else on earth. This is why you 293 00:16:45,520 --> 00:16:47,640 Speaker 1: will you will see. You know, there's so many different 294 00:16:48,560 --> 00:16:51,520 Speaker 1: documentaries about Christmas Islands. One there's so much great footage 295 00:16:52,320 --> 00:16:56,400 Speaker 1: because they they go on these enormous migrations and we're 296 00:16:56,400 --> 00:16:59,920 Speaker 1: talking a several kilometer journey each year. Yeah, this is 297 00:17:00,040 --> 00:17:03,080 Speaker 1: crab Apocalypse. This is where the real show is on 298 00:17:03,160 --> 00:17:07,119 Speaker 1: Christmas Island. So around the beginning of the rainy season, 299 00:17:07,160 --> 00:17:11,119 Speaker 1: which is sometime October through December, the red crabs begin 300 00:17:11,280 --> 00:17:15,320 Speaker 1: this migration for their breeding cycle. And the migration begins 301 00:17:15,320 --> 00:17:18,720 Speaker 1: with the males, usually the biggest males, who will crawl 302 00:17:18,800 --> 00:17:22,159 Speaker 1: out over land from their forest burrows to the shore 303 00:17:22,640 --> 00:17:25,720 Speaker 1: where they're going to eventually get there and dig new 304 00:17:25,760 --> 00:17:29,240 Speaker 1: burrows for mating. And as the males make this journey, 305 00:17:29,240 --> 00:17:32,000 Speaker 1: the females eventually joined them in the journey and they 306 00:17:32,080 --> 00:17:35,359 Speaker 1: march towards the sea. Now, once the crabs reached the shore, 307 00:17:35,440 --> 00:17:38,520 Speaker 1: but before they dig their burrows to mate, uh, they 308 00:17:38,560 --> 00:17:42,760 Speaker 1: typically wash themselves off in seawater, though strangely enough, they 309 00:17:42,760 --> 00:17:45,200 Speaker 1: have to be careful not to get fully sucked out 310 00:17:45,200 --> 00:17:48,480 Speaker 1: into the sea, because these are land dwelling crabs. This 311 00:17:48,560 --> 00:17:51,679 Speaker 1: is how they've evolved, and they can neither breathe underwater, 312 00:17:51,800 --> 00:17:54,680 Speaker 1: nor can they swim very well. These are crabs who 313 00:17:54,680 --> 00:17:58,679 Speaker 1: are not very good at being crabs. Yeah, so the 314 00:17:58,680 --> 00:18:01,800 Speaker 1: truly aquatic crabs in the neighborhood are just probably watching 315 00:18:01,800 --> 00:18:05,280 Speaker 1: this in halfing at them. Yeah, but there's so many 316 00:18:05,320 --> 00:18:06,919 Speaker 1: of them. How could you laugh at them? Because they 317 00:18:06,960 --> 00:18:08,639 Speaker 1: could really gang up on you if they got a 318 00:18:08,680 --> 00:18:11,879 Speaker 1: hold of your right But so they would rinse themselves 319 00:18:11,880 --> 00:18:14,200 Speaker 1: off in the sea water. And then the males dig 320 00:18:14,240 --> 00:18:17,480 Speaker 1: the burrows. Now, sometimes when they dig the burrows, usually 321 00:18:17,480 --> 00:18:19,919 Speaker 1: they'll go up a little bit from the beach and 322 00:18:20,320 --> 00:18:23,240 Speaker 1: one of the forested areas just right by the beach, 323 00:18:23,600 --> 00:18:26,040 Speaker 1: and they'll dig these burrows. And sometimes the males have 324 00:18:26,080 --> 00:18:28,880 Speaker 1: to defend their burrows from other males, who of course think, hey, 325 00:18:28,880 --> 00:18:31,200 Speaker 1: why dig one when you can just claim somebody else's. 326 00:18:31,640 --> 00:18:34,679 Speaker 1: So there are sometimes these fights and dominance displays, a 327 00:18:34,680 --> 00:18:38,080 Speaker 1: lot of claw waving to keep the burrows secure. And 328 00:18:38,119 --> 00:18:40,200 Speaker 1: then of course the females come in and they will 329 00:18:40,240 --> 00:18:43,000 Speaker 1: find a male with a burrow and initiate the mating. 330 00:18:43,480 --> 00:18:47,080 Speaker 1: And by the way, if you've never watched crabs mating before, 331 00:18:47,720 --> 00:18:51,639 Speaker 1: it's one of the funnier looking types of animal sex. 332 00:18:51,680 --> 00:18:54,280 Speaker 1: I think it's just crabs look funny no matter what 333 00:18:54,320 --> 00:18:58,040 Speaker 1: they're doing. But also if you can just watch their 334 00:18:58,160 --> 00:19:01,840 Speaker 1: eyes while they're mating, it's really something special. It's you know, 335 00:19:01,880 --> 00:19:04,639 Speaker 1: it's like two google eyed robots trying to be sexy 336 00:19:04,680 --> 00:19:07,440 Speaker 1: at each other and then throwing some claws and swiveling 337 00:19:07,480 --> 00:19:10,440 Speaker 1: mouth parts. It's just awesome. Now you mentioned the waving 338 00:19:10,440 --> 00:19:11,920 Speaker 1: of the clause, I want to I was reading a 339 00:19:11,960 --> 00:19:14,760 Speaker 1: little bit about crab clause in Douglas j Emlin's book 340 00:19:14,800 --> 00:19:17,160 Speaker 1: Animal Weapons. Uh And he goes. He spends a little 341 00:19:17,160 --> 00:19:18,919 Speaker 1: bit of time talking about, you know, how these are 342 00:19:19,000 --> 00:19:22,919 Speaker 1: high energy adaptations to pack with powerful muscles. They need 343 00:19:22,960 --> 00:19:25,960 Speaker 1: to be able to break through the exo skeletons of 344 00:19:25,960 --> 00:19:29,399 Speaker 1: of rival males in many cases. Uh And he mostly 345 00:19:29,400 --> 00:19:31,960 Speaker 1: looks at fidler crabs in this book. But but but 346 00:19:31,960 --> 00:19:35,440 Speaker 1: it's interesting stuff. The economics of not only having growing, 347 00:19:35,800 --> 00:19:40,080 Speaker 1: evolving gigantic class but waving them around, because that's that's 348 00:19:40,119 --> 00:19:43,000 Speaker 1: part of having the cleaving clause or a claw, is 349 00:19:43,040 --> 00:19:47,840 Speaker 1: to wave that sucker around, yeah, or like flexing your muscles, 350 00:19:47,920 --> 00:19:50,080 Speaker 1: like showing off the guns. Yeah, you have to show 351 00:19:50,080 --> 00:19:53,600 Speaker 1: off the guns. That's that's part of having them, right. Yeah. 352 00:19:53,640 --> 00:19:57,720 Speaker 1: So the female will generally find a male and a 353 00:19:57,760 --> 00:19:59,640 Speaker 1: male with the burrow and they will mate. And then 354 00:19:59,680 --> 00:20:01,760 Speaker 1: after are mating, what the males do is they just 355 00:20:01,800 --> 00:20:04,679 Speaker 1: pack up and headback inland. Their work is done, and 356 00:20:04,720 --> 00:20:08,320 Speaker 1: they leave the females by themselves in these seaside burrows. 357 00:20:08,880 --> 00:20:12,159 Speaker 1: And there's another interesting thing about this. Okay, so the 358 00:20:12,200 --> 00:20:16,760 Speaker 1: red crabs are sort of moon worshiping druids. The breeding 359 00:20:16,800 --> 00:20:20,520 Speaker 1: migration has to be timed exactly according to the cycle 360 00:20:20,600 --> 00:20:23,600 Speaker 1: of the moon because the cycle of the moon affects 361 00:20:23,600 --> 00:20:26,960 Speaker 1: the tides. So the adult crabs arrive at the shore 362 00:20:27,040 --> 00:20:29,520 Speaker 1: and then they mate, and after mating, the females produce 363 00:20:29,600 --> 00:20:32,760 Speaker 1: eggs within about three days, and then they remain in 364 00:20:32,800 --> 00:20:36,560 Speaker 1: their burrows for another twelve or thirteen days. And after 365 00:20:36,600 --> 00:20:39,480 Speaker 1: this they emerge from the hole in the ground and 366 00:20:39,520 --> 00:20:41,960 Speaker 1: they release their eggs into the sea water. And it 367 00:20:42,080 --> 00:20:45,000 Speaker 1: has to be timed exactly at the turn of high tide, 368 00:20:45,080 --> 00:20:47,800 Speaker 1: as the moon goes from its last quarter to a 369 00:20:47,840 --> 00:20:50,800 Speaker 1: new moon. And this is because it's when the tide 370 00:20:50,840 --> 00:20:54,280 Speaker 1: conditions are just right to be releasing the young. But 371 00:20:54,560 --> 00:20:57,840 Speaker 1: if the migration is delayed by weather so that breeding 372 00:20:57,880 --> 00:21:00,440 Speaker 1: can't be timed exactly right with the phase of the moon, 373 00:21:00,520 --> 00:21:02,679 Speaker 1: the crabs will just wait. They'll just wait until the 374 00:21:02,720 --> 00:21:05,280 Speaker 1: next month to breed because it it's not it's not 375 00:21:05,359 --> 00:21:08,520 Speaker 1: going the moon isn't right. So when the time is right, 376 00:21:08,760 --> 00:21:11,639 Speaker 1: the females release their eggs acts, which looks kind of 377 00:21:11,680 --> 00:21:14,240 Speaker 1: like a weird foamy sponge that they carry on the 378 00:21:14,320 --> 00:21:17,040 Speaker 1: underside of their bodies. They release these eggs acts into 379 00:21:17,080 --> 00:21:20,560 Speaker 1: the water. Yet again, I can't help but notice that 380 00:21:20,640 --> 00:21:24,080 Speaker 1: my wonder at these animals is combined with hilarity on 381 00:21:24,160 --> 00:21:27,080 Speaker 1: seeing this, because in some cases the female crabs have 382 00:21:27,200 --> 00:21:30,240 Speaker 1: to release their eggs into like rough surf while clinging 383 00:21:30,280 --> 00:21:32,879 Speaker 1: to rocks above the water, and they're trying to be 384 00:21:32,920 --> 00:21:35,160 Speaker 1: careful not to fall in. And when you see footage 385 00:21:35,200 --> 00:21:38,520 Speaker 1: of this, the way they're just frantically shaking their bodies 386 00:21:38,600 --> 00:21:41,840 Speaker 1: to knock the eggs acts off, dumping thousands of eggs 387 00:21:41,840 --> 00:21:44,920 Speaker 1: off a cliff, I can't help but laugh. It's funny. 388 00:21:44,960 --> 00:21:47,679 Speaker 1: And then also sometimes they'll they'll go into the surf 389 00:21:47,720 --> 00:21:50,200 Speaker 1: on a beach and you'll see them like raising their 390 00:21:50,240 --> 00:21:55,760 Speaker 1: claws and shaking their bodies, like get off, just dumping 391 00:21:55,800 --> 00:21:57,679 Speaker 1: all these eggs off into the water. I don't know, 392 00:21:57,760 --> 00:22:02,240 Speaker 1: it's it's funny to me. Well, by in comparisons, they're 393 00:22:02,240 --> 00:22:05,160 Speaker 1: maybe not great moms, but by but by Christmas Island 394 00:22:05,200 --> 00:22:08,879 Speaker 1: red Crab standards moms of the year. Yeah, exactly, and 395 00:22:09,040 --> 00:22:11,040 Speaker 1: that this does make me think about the ways that 396 00:22:11,080 --> 00:22:13,600 Speaker 1: we anthropomorphize good parenting. I want to come back to 397 00:22:13,640 --> 00:22:16,359 Speaker 1: that in just a minute. So the eggs are released 398 00:22:16,359 --> 00:22:19,040 Speaker 1: into the surf and they hatch pretty much immediately, and 399 00:22:19,040 --> 00:22:21,960 Speaker 1: then you've got these hatchling crab larvae that live in 400 00:22:22,000 --> 00:22:26,120 Speaker 1: the water for about a month, transforming through large larval stages, 401 00:22:26,160 --> 00:22:30,320 Speaker 1: and then they returned the shore in this seething foam 402 00:22:30,560 --> 00:22:33,679 Speaker 1: of what looks like pink ants. This is also just 403 00:22:33,800 --> 00:22:37,159 Speaker 1: astonishing to see, like the original migration from the forest 404 00:22:37,200 --> 00:22:40,560 Speaker 1: to the shore with the beaches and rocks covered in 405 00:22:40,640 --> 00:22:46,520 Speaker 1: this surging, pink shag carpet of tiny millimeter sized baby crabs. 406 00:22:46,960 --> 00:22:50,080 Speaker 1: And then they mold and immediately after molting they are 407 00:22:50,119 --> 00:22:53,120 Speaker 1: committed to an air breathing life on land and they 408 00:22:53,119 --> 00:22:56,160 Speaker 1: travel inland to do as their ancestors did before them, 409 00:22:56,480 --> 00:22:59,480 Speaker 1: and this growth from about a five millimeter baby crab 410 00:22:59,560 --> 00:23:02,880 Speaker 1: staged adulthood usually takes about four years, during which time 411 00:23:02,880 --> 00:23:05,920 Speaker 1: they mostly tend to hide out undercover until they get 412 00:23:05,920 --> 00:23:08,919 Speaker 1: big enough to fend for themselves. But yeah, back to 413 00:23:09,000 --> 00:23:12,760 Speaker 1: this idea about the way we look at non human 414 00:23:12,800 --> 00:23:15,760 Speaker 1: animals and tend to to judge their parenting. I mean, 415 00:23:15,800 --> 00:23:17,960 Speaker 1: that's inherently what I was doing when I think it's 416 00:23:17,960 --> 00:23:21,280 Speaker 1: funny just watching the mother crabs chuck their eggs off 417 00:23:21,280 --> 00:23:26,439 Speaker 1: a cliff. But it's like it's hilarious watching a crab 418 00:23:26,520 --> 00:23:29,080 Speaker 1: vigorously shake its body to knock all the eggs off 419 00:23:29,119 --> 00:23:32,520 Speaker 1: and stuff. But it's because we've so deeply internalized the 420 00:23:32,560 --> 00:23:36,399 Speaker 1: brood protection tendencies of mammals. Mammals tend to keep their 421 00:23:36,440 --> 00:23:39,280 Speaker 1: offspring close and take care of them for for like 422 00:23:39,320 --> 00:23:42,480 Speaker 1: extended periods of time while they mature, and that would 423 00:23:42,520 --> 00:23:45,199 Speaker 1: make no sense for crabs to do. First of all, 424 00:23:45,280 --> 00:23:47,320 Speaker 1: of course, it is just mechanically the case, because the 425 00:23:47,359 --> 00:23:50,560 Speaker 1: eggs need to hatch in the water. That's what chemically 426 00:23:50,680 --> 00:23:55,040 Speaker 1: and mechanically they do. But also mathematically, the parents have 427 00:23:55,119 --> 00:23:59,119 Speaker 1: a totally different relationship with their offspring. Mammals tend to produce, 428 00:23:59,200 --> 00:24:02,080 Speaker 1: you know, relatively small numbers of offspring and invest a 429 00:24:02,119 --> 00:24:05,280 Speaker 1: lot of energy into caring for and protecting them. But 430 00:24:05,359 --> 00:24:07,040 Speaker 1: I was trying to do a little bit of rough 431 00:24:07,119 --> 00:24:09,920 Speaker 1: math about the red crab. So let's assume there are 432 00:24:09,920 --> 00:24:13,480 Speaker 1: fifty million adult red crabs on the island, and then 433 00:24:13,480 --> 00:24:16,119 Speaker 1: you've got mated pairs, and each mated pair of adult 434 00:24:16,160 --> 00:24:19,399 Speaker 1: crabs produces tens of thousands of eggs. I've seen a 435 00:24:19,440 --> 00:24:23,280 Speaker 1: common figure of a hundred thousand eggs per female crab sited. 436 00:24:23,640 --> 00:24:27,159 Speaker 1: So if fifty million crabs made it and produced twenty 437 00:24:27,160 --> 00:24:30,440 Speaker 1: five million eggs sponges, and each of those had a 438 00:24:30,520 --> 00:24:33,960 Speaker 1: hundred thousand eggs in it, and all those eggs survived 439 00:24:33,960 --> 00:24:38,720 Speaker 1: to adulthood, that would be two trillion, five hundred billion crabs. 440 00:24:39,240 --> 00:24:41,640 Speaker 1: Now Christmas Island is about a hundred and thirty five 441 00:24:41,680 --> 00:24:44,359 Speaker 1: square kilometers. If my math is right, this means that 442 00:24:44,480 --> 00:24:47,960 Speaker 1: just after one year there would be a Christmas Island 443 00:24:48,000 --> 00:24:52,040 Speaker 1: would have eighteen point five billion crabs per square kilometer. 444 00:24:52,200 --> 00:24:56,080 Speaker 1: So you're saying, as a red crab mom, you have 445 00:24:56,119 --> 00:24:57,720 Speaker 1: to be willing to let some of those crabs go 446 00:24:57,800 --> 00:25:00,920 Speaker 1: because you have you have the numbers on your side, right, 447 00:25:00,960 --> 00:25:03,480 Speaker 1: I mean, it's just a totally different way of of 448 00:25:03,520 --> 00:25:07,520 Speaker 1: having a relationship between generations, right. They're going for for numbers. 449 00:25:07,600 --> 00:25:10,320 Speaker 1: You know, it's quantity rather than quality. And it's just 450 00:25:10,440 --> 00:25:13,919 Speaker 1: impossible for all those young to sustainably survive. Even if 451 00:25:13,960 --> 00:25:17,200 Speaker 1: a decent fraction of them survived, it would be ridiculous. 452 00:25:17,320 --> 00:25:20,000 Speaker 1: Only a tiny fraction of them can possibly make it 453 00:25:20,040 --> 00:25:24,440 Speaker 1: to adulthood in any ecologically sustainable way. And so most 454 00:25:24,520 --> 00:25:27,240 Speaker 1: they get dumped out into the water to hatch, never 455 00:25:27,359 --> 00:25:29,560 Speaker 1: make it back to shore alive. They get washed out 456 00:25:29,560 --> 00:25:33,560 Speaker 1: to sea, never to return. Apparently, whale sharks migrate to 457 00:25:33,720 --> 00:25:36,960 Speaker 1: the Christmas Island area to eat red crab larvae when 458 00:25:36,960 --> 00:25:39,840 Speaker 1: they hatch, and among those that do make it back 459 00:25:39,840 --> 00:25:42,400 Speaker 1: to the beach in that in that you know foamy 460 00:25:42,440 --> 00:25:45,280 Speaker 1: pink shag carpet I mentioned, they're obviously going to be 461 00:25:45,359 --> 00:25:47,840 Speaker 1: pretty easy prey at that stage too. You can even 462 00:25:47,880 --> 00:25:50,640 Speaker 1: sometimes see I've seen footage of this of adult red 463 00:25:50,680 --> 00:25:54,160 Speaker 1: crabs just kind of shoveling clawfulls of young red crabs 464 00:25:54,200 --> 00:25:57,119 Speaker 1: into their mouths because hey, what are the chances that 465 00:25:57,200 --> 00:26:00,199 Speaker 1: these are mine? It's pretty slim. Again, it's a numbers game. Well, 466 00:26:00,240 --> 00:26:02,520 Speaker 1: plus it's they're just against so many of them. It's like, 467 00:26:02,560 --> 00:26:05,840 Speaker 1: if you make way too much a pancake batter, uh, 468 00:26:06,040 --> 00:26:09,040 Speaker 1: you may treat yourself to a few spoonfuls of unclick 469 00:26:09,119 --> 00:26:12,679 Speaker 1: pancake batter. I mean, why not, it's there. You can 470 00:26:12,720 --> 00:26:15,240 Speaker 1: only make so many pancakes. You can make similar argument. 471 00:26:15,280 --> 00:26:17,359 Speaker 1: You'd be like, look, if I made all of this 472 00:26:17,440 --> 00:26:20,440 Speaker 1: into pancakes, our house would be packed with pancakes six 473 00:26:20,480 --> 00:26:25,040 Speaker 1: ft high exactly. But anyway, given this kind of life cycle, 474 00:26:25,080 --> 00:26:27,040 Speaker 1: in these kind of odds, the way to be a 475 00:26:27,080 --> 00:26:29,960 Speaker 1: good parent is to do exactly what the female crabs do. 476 00:26:30,320 --> 00:26:32,640 Speaker 1: They shake them off into the water where they've got 477 00:26:32,640 --> 00:26:34,880 Speaker 1: a chance, and then they call it a day. There's 478 00:26:34,920 --> 00:26:36,800 Speaker 1: nothing more you can do at that point. And if 479 00:26:36,840 --> 00:26:39,600 Speaker 1: somehow you were still around when they hatched and malted, 480 00:26:39,640 --> 00:26:42,560 Speaker 1: who knows, you might just gobble them up. So, despite 481 00:26:42,560 --> 00:26:45,760 Speaker 1: how funny it looks, I rebuke my instincts. I do 482 00:26:45,840 --> 00:26:48,159 Speaker 1: not think that the red crabs are bad parents. I 483 00:26:48,160 --> 00:26:50,920 Speaker 1: think they're awesome crab parents. All Right, we're gonna take 484 00:26:50,920 --> 00:26:52,439 Speaker 1: a quick break and when we come back, we're going 485 00:26:52,480 --> 00:26:54,200 Speaker 1: to get into the human element. What happens when we 486 00:26:54,240 --> 00:26:59,680 Speaker 1: have the human element to the red crab element? Alright, 487 00:26:59,680 --> 00:27:03,320 Speaker 1: we're bad. Now. We discussed earlier how crazy these migrations are. 488 00:27:03,560 --> 00:27:06,480 Speaker 1: You know, when the island can sometimes in areas, become 489 00:27:06,560 --> 00:27:09,399 Speaker 1: just thick with crabs that are moving from forest to 490 00:27:09,480 --> 00:27:13,399 Speaker 1: shore or returning from shore to forest. And this doesn't 491 00:27:13,400 --> 00:27:16,359 Speaker 1: even take into consideration the fact that sometimes there are 492 00:27:16,440 --> 00:27:20,440 Speaker 1: multiple waves of migration during the same year. So you've 493 00:27:20,440 --> 00:27:23,520 Speaker 1: got crabs going both ways. Like one set of crabs 494 00:27:23,600 --> 00:27:25,679 Speaker 1: they moved down to the shore, and then there's another, 495 00:27:26,240 --> 00:27:29,120 Speaker 1: uh you know, trigger of the rainy season, another set 496 00:27:29,160 --> 00:27:31,680 Speaker 1: of crabs they start moving to the shore. Then then 497 00:27:31,720 --> 00:27:33,600 Speaker 1: the other ones are going home. So you can have 498 00:27:33,640 --> 00:27:35,919 Speaker 1: crabs going this way, crabs going that way. There on 499 00:27:35,960 --> 00:27:38,320 Speaker 1: the golf course, there on the streets, there in the 500 00:27:38,359 --> 00:27:42,520 Speaker 1: grocery store. I mean, it can become quite thick with 501 00:27:42,600 --> 00:27:45,840 Speaker 1: crabs on Christmas Island. And yet there are people here, 502 00:27:46,640 --> 00:27:50,159 Speaker 1: that's right, And those people have vehicles. Yeah that they 503 00:27:50,160 --> 00:27:52,480 Speaker 1: also have pets. Uh. We'll get into some of those 504 00:27:52,600 --> 00:27:55,600 Speaker 1: complications in a bit, but just the roads. You're talking 505 00:27:55,640 --> 00:27:58,560 Speaker 1: about something like a million crabs a year crushed by 506 00:27:58,640 --> 00:28:01,959 Speaker 1: road traffic on Christmas High but that's still only gonna 507 00:28:01,960 --> 00:28:04,520 Speaker 1: shake out to something like one percent of the population. 508 00:28:04,960 --> 00:28:09,360 Speaker 1: And the dead, by the way, are apparently swiftly cannibalize again. Crabs. 509 00:28:09,440 --> 00:28:11,320 Speaker 1: Crabs are gonna do what crabs are gonna do. No. 510 00:28:11,440 --> 00:28:14,280 Speaker 1: I mentioned earlier that there's this great old British TV 511 00:28:14,400 --> 00:28:17,600 Speaker 1: documentary called Kingdom of the Crabs and narrated by David 512 00:28:17,600 --> 00:28:21,359 Speaker 1: Attenborough from nineteen I think, yeah, that was the same 513 00:28:21,480 --> 00:28:25,439 Speaker 1: year that we got John Carpenters They Live, Killer Clowns 514 00:28:25,440 --> 00:28:28,600 Speaker 1: from Outer Space, The Blob the remake, the really cool 515 00:28:28,640 --> 00:28:31,360 Speaker 1: eighties remake, as well as of course Mac and Me. Well, 516 00:28:31,359 --> 00:28:33,640 Speaker 1: this is right up there with those. But it's got 517 00:28:33,680 --> 00:28:35,720 Speaker 1: so many great moments, and one of the best moments 518 00:28:35,720 --> 00:28:39,120 Speaker 1: from it is when you're watching hundreds of crabs scuttling 519 00:28:39,120 --> 00:28:42,400 Speaker 1: across a pair of railroad tracks, and then a train 520 00:28:42,520 --> 00:28:47,200 Speaker 1: emerges in the background and it's barreling towards the crab crossing, 521 00:28:47,720 --> 00:28:50,560 Speaker 1: and then the crabs show no sign of getting out 522 00:28:50,560 --> 00:28:53,480 Speaker 1: of the way, and then the train conductor starts blowing 523 00:28:53,560 --> 00:28:56,120 Speaker 1: his horn at the crabs as if that's going to 524 00:28:56,360 --> 00:28:59,560 Speaker 1: deter them. I guess it's like when people like they 525 00:28:59,600 --> 00:29:01,840 Speaker 1: stop in the road because the turtle is crossing and 526 00:29:01,840 --> 00:29:05,960 Speaker 1: they honked their horn at it. I never actually haunk 527 00:29:06,000 --> 00:29:09,280 Speaker 1: my Hornet's say, squirrels chip bunks, but I will almost 528 00:29:09,320 --> 00:29:12,400 Speaker 1: wreck my vehicle to avoid them. But I I guess 529 00:29:12,440 --> 00:29:15,720 Speaker 1: that's human nature. Like you don't want to squish crabs unnecessarily. 530 00:29:15,760 --> 00:29:18,080 Speaker 1: I mean maybe some people do. There are probably a 531 00:29:18,080 --> 00:29:19,720 Speaker 1: few people on the island who kind of get off 532 00:29:19,720 --> 00:29:21,600 Speaker 1: on it. Well, I've read that it can. It can 533 00:29:21,640 --> 00:29:25,280 Speaker 1: also hurt your tires. Yeah, you have people with flat 534 00:29:25,320 --> 00:29:29,240 Speaker 1: tires due to the crabs. Probably hurts trains less, probably, um. 535 00:29:31,200 --> 00:29:33,160 Speaker 1: But the humans have had to put in place many 536 00:29:33,240 --> 00:29:37,880 Speaker 1: steps to help the crabs cope with roads and tracks 537 00:29:37,920 --> 00:29:41,560 Speaker 1: and the other ways that we have unfortunately disrupted their 538 00:29:41,600 --> 00:29:43,920 Speaker 1: migration zones. I mean, it's not the crabs fault, right, 539 00:29:43,960 --> 00:29:46,520 Speaker 1: They didn't ask us to put a road there, but 540 00:29:46,760 --> 00:29:49,480 Speaker 1: railroad tracks there to do all that kind of stuff. 541 00:29:49,520 --> 00:29:53,320 Speaker 1: So these adaptations are are pretty interesting. They include barriers 542 00:29:53,360 --> 00:29:55,479 Speaker 1: of course around the edges of roads and put walls 543 00:29:55,520 --> 00:29:57,960 Speaker 1: around the roads to keep the crabs from walking onto 544 00:29:57,960 --> 00:30:01,880 Speaker 1: the roads. And these lead to of crab funnels that 545 00:30:02,080 --> 00:30:05,760 Speaker 1: route the crabs to specially designed safe crossings, so you 546 00:30:05,840 --> 00:30:08,760 Speaker 1: might have an underpass with a great on top of it, 547 00:30:09,040 --> 00:30:12,520 Speaker 1: or even there's even a five meter high crab bridge 548 00:30:12,680 --> 00:30:16,040 Speaker 1: climbable by crab to help them over one stretch of road. 549 00:30:16,400 --> 00:30:17,960 Speaker 1: Oh yeah, and you included a picture of these in 550 00:30:17,960 --> 00:30:20,720 Speaker 1: our notes. It's pretty incredible because it looks like one 551 00:30:20,720 --> 00:30:25,640 Speaker 1: of the recognizers those enemy ships in the Tron movies. Yeah, 552 00:30:26,040 --> 00:30:28,240 Speaker 1: it looks like like that, the big clamp that comes 553 00:30:28,240 --> 00:30:30,800 Speaker 1: down on top of you, right, except instead of being 554 00:30:30,840 --> 00:30:34,160 Speaker 1: made out of brightly colored light, it's covered in brightly 555 00:30:34,360 --> 00:30:38,800 Speaker 1: colored red crabs right now. Interestingly enough, early accounts of 556 00:30:38,840 --> 00:30:42,400 Speaker 1: Christmas Island make no real mention of the crab hoards, 557 00:30:43,040 --> 00:30:45,160 Speaker 1: so you could you can look at that one of 558 00:30:45,200 --> 00:30:48,600 Speaker 1: two ways, right, Well, either it didn't occur in at 559 00:30:48,680 --> 00:30:51,640 Speaker 1: least with the same at the same level, or they 560 00:30:51,680 --> 00:30:54,840 Speaker 1: just forgot to mention it, which seems unlikely, so maybe 561 00:30:54,880 --> 00:30:58,320 Speaker 1: they didn't witness it. Well, it's true too, but there 562 00:30:58,400 --> 00:31:02,680 Speaker 1: is this suspected link between the current levels and the 563 00:31:03,680 --> 00:31:07,560 Speaker 1: recent levels of of of the red crab population with 564 00:31:07,800 --> 00:31:11,720 Speaker 1: the extinction of two species of rat that were on 565 00:31:11,760 --> 00:31:15,920 Speaker 1: the island when Europeans first arrived. And uh, and it's 566 00:31:15,960 --> 00:31:19,040 Speaker 1: possible that these two species of rat may have kept 567 00:31:19,200 --> 00:31:23,320 Speaker 1: the populations more in check. What are these rats alright? 568 00:31:23,360 --> 00:31:28,160 Speaker 1: One is called mcclear's rat or memor rattis McCleary and 569 00:31:28,200 --> 00:31:33,240 Speaker 1: the other is the bulldog rat or Rattus nativitatis. And 570 00:31:33,440 --> 00:31:37,200 Speaker 1: those are just two of only five native mammal species 571 00:31:37,200 --> 00:31:40,800 Speaker 1: on Christmas Island to have been officially listed as extinct 572 00:31:41,440 --> 00:31:44,240 Speaker 1: since humans showed up. That being both of these rats, 573 00:31:44,280 --> 00:31:47,600 Speaker 1: and the reason that they went extinct, it's it's probably 574 00:31:47,600 --> 00:31:51,680 Speaker 1: because exotic rodents were brought in by early human colonizers 575 00:31:51,800 --> 00:31:54,680 Speaker 1: or brought in. I would say they just came along 576 00:31:54,720 --> 00:31:58,160 Speaker 1: with let rats do. Okay, So the ideas that humans 577 00:31:58,200 --> 00:32:02,000 Speaker 1: brought different kinds of rodents, those rodents out competed the 578 00:32:02,080 --> 00:32:04,960 Speaker 1: native rodents, but those rodents weren't as much of a 579 00:32:05,000 --> 00:32:08,720 Speaker 1: competition with the red crabs. Well it's more than just 580 00:32:08,760 --> 00:32:12,920 Speaker 1: outcompete as apparently like straight up killed them off with illness. 581 00:32:13,600 --> 00:32:15,680 Speaker 1: It was looking at a two thousand eight study published 582 00:32:15,680 --> 00:32:19,560 Speaker 1: in PLS one, and they pointed out that there seems 583 00:32:19,560 --> 00:32:21,200 Speaker 1: to be a direct cause here, and it seems to 584 00:32:21,200 --> 00:32:24,680 Speaker 1: be disease. They collected DNA samples from the islands now 585 00:32:24,800 --> 00:32:28,480 Speaker 1: extinct native rats via late nineteenth in early twentieth century 586 00:32:28,560 --> 00:32:32,560 Speaker 1: museum specimens, and they attributed the extinction event here to 587 00:32:33,080 --> 00:32:38,600 Speaker 1: ship jumping black rats infected with the protozoan Tripanasoma Louizy, 588 00:32:39,360 --> 00:32:42,719 Speaker 1: an organism that is related to an organism that causes 589 00:32:42,720 --> 00:32:47,560 Speaker 1: sleeping sickness in humans. And indeed, Native Island rats were 590 00:32:47,600 --> 00:32:51,200 Speaker 1: seen to stagger around following the arrival of the S 591 00:32:51,400 --> 00:32:56,440 Speaker 1: S Hindustan in eight and this protozoan is light is 592 00:32:56,480 --> 00:32:59,680 Speaker 1: likely spread by fleas, so we have you know, it's 593 00:32:59,680 --> 00:33:02,600 Speaker 1: a similar situation that we've seen with certainly with with 594 00:33:02,680 --> 00:33:06,640 Speaker 1: human populations and UH and other organisms, where an exotic 595 00:33:07,200 --> 00:33:10,760 Speaker 1: variant brought in a parasite that the UH, the native 596 00:33:10,760 --> 00:33:13,640 Speaker 1: inhabitants were just simply unable to deal with. Now, in 597 00:33:13,720 --> 00:33:18,000 Speaker 1: terms of other native Christmas Island mammals, others have had 598 00:33:18,040 --> 00:33:20,840 Speaker 1: a tough time as well. The Christmas Island shrew is 599 00:33:20,880 --> 00:33:31,160 Speaker 1: critically endangered. There's also a particular batu, the Christmas Island Pipistrelli. Yes, 600 00:33:31,440 --> 00:33:34,600 Speaker 1: thank you for help on that one. Now, it's it's 601 00:33:34,960 --> 00:33:37,520 Speaker 1: a ute name. It is a cute name, a cute 602 00:33:37,600 --> 00:33:41,320 Speaker 1: name for a bat. It's critically endangered, if not outright extinct, 603 00:33:41,400 --> 00:33:45,280 Speaker 1: and apparently the reasoning behind that is is not completely understood. 604 00:33:45,560 --> 00:33:48,760 Speaker 1: There's also the Christmas Island flying fox, which is another 605 00:33:48,800 --> 00:33:52,000 Speaker 1: type of bat. It is also in decline for unknown reasons. 606 00:33:52,600 --> 00:33:55,360 Speaker 1: And then you have the exotic mammals. We've already mentioned 607 00:33:55,440 --> 00:33:58,000 Speaker 1: black rats, but you also have a house mice, you 608 00:33:58,040 --> 00:34:01,040 Speaker 1: have feral cats and wild dog. Now do we know 609 00:34:01,360 --> 00:34:04,720 Speaker 1: what the explicit relationship between that change in the mammal 610 00:34:04,800 --> 00:34:09,239 Speaker 1: populations and the surge and crabs is. The belief is 611 00:34:09,360 --> 00:34:13,160 Speaker 1: that those populated the original populations of rodents were helping 612 00:34:13,160 --> 00:34:16,719 Speaker 1: to keep the population of crabs in check, and apparently 613 00:34:16,840 --> 00:34:20,360 Speaker 1: the the the exotic mammals have not been able to 614 00:34:20,440 --> 00:34:23,359 Speaker 1: keep their numbers in check the same in the same rate. 615 00:34:23,560 --> 00:34:27,439 Speaker 1: I see, So they're not adapted to to crab Island, right, Yeah, 616 00:34:27,640 --> 00:34:30,560 Speaker 1: it's it's one of those situations where again you just 617 00:34:30,640 --> 00:34:33,640 Speaker 1: see humans show up in the unbalanced things. Yes, Now, 618 00:34:33,760 --> 00:34:36,400 Speaker 1: in the case of the red crabs, it would almost 619 00:34:36,440 --> 00:34:39,560 Speaker 1: seem like the unbalancing made more spectacle. Right. Like, the 620 00:34:39,560 --> 00:34:41,719 Speaker 1: reason we're talking about Christmas Island is because we have 621 00:34:41,800 --> 00:34:46,319 Speaker 1: this enormous surge that arguably might not be the same 622 00:34:46,400 --> 00:34:49,640 Speaker 1: level uh if we had also not managed to kill 623 00:34:49,680 --> 00:34:53,320 Speaker 1: off two whole species of rodents on the island. True, 624 00:34:53,800 --> 00:34:56,480 Speaker 1: and there's going to be even more stuff along those 625 00:34:56,520 --> 00:35:00,000 Speaker 1: lines coming up. So there are actually multiple ongoing through 626 00:35:00,040 --> 00:35:02,759 Speaker 1: rats to the life cycle of these amazing animals. If 627 00:35:02,840 --> 00:35:05,919 Speaker 1: if you care about the beauty of the crab army 628 00:35:06,000 --> 00:35:09,520 Speaker 1: scuttling through the forests, you should care about these issues. 629 00:35:09,680 --> 00:35:13,520 Speaker 1: One is climate related. So there is a paper from 630 00:35:14,480 --> 00:35:18,560 Speaker 1: in Global Change Biology called Linking L neno Local rainfall 631 00:35:18,600 --> 00:35:22,840 Speaker 1: and migration timing in a tropical migratory species by Alison K. 632 00:35:22,960 --> 00:35:26,280 Speaker 1: Shaw and Catherine A. Kelly, and the authors here find 633 00:35:26,320 --> 00:35:31,080 Speaker 1: that species who's mating and migratory behaviors are determined by weather, 634 00:35:31,320 --> 00:35:34,520 Speaker 1: like the Christmas Island red crab. Remember it's the it's 635 00:35:34,520 --> 00:35:37,360 Speaker 1: certain things about the beginning of the rainy season that 636 00:35:37,480 --> 00:35:40,759 Speaker 1: tell them time to go to the beach and mate. Uh. 637 00:35:41,120 --> 00:35:44,880 Speaker 1: They will probably be adversely affected by the way climate 638 00:35:45,000 --> 00:35:48,080 Speaker 1: change is upsetting normal weather patterns that were used to 639 00:35:48,880 --> 00:35:51,600 Speaker 1: So the authors write, quote, we find that the timing 640 00:35:51,640 --> 00:35:55,279 Speaker 1: of the annual crab breeding migration is closely related to 641 00:35:55,280 --> 00:35:58,840 Speaker 1: the amount of rain that falls during a migration window 642 00:35:59,360 --> 00:36:03,040 Speaker 1: period prior to potential egg release states, which is in 643 00:36:03,120 --> 00:36:06,960 Speaker 1: turn related to the Southern Oscillation index and atmospheric l 644 00:36:07,040 --> 00:36:11,719 Speaker 1: ne NEO Southern oscillation index. As reproduction in this species 645 00:36:11,800 --> 00:36:15,799 Speaker 1: is conditional on successful migration, they don't reproduce if they 646 00:36:15,800 --> 00:36:19,920 Speaker 1: don't migrate, major changes in migration patterns could have detrimental 647 00:36:19,960 --> 00:36:23,600 Speaker 1: consequences for the survival of the species. So, in other words, 648 00:36:23,880 --> 00:36:26,880 Speaker 1: climate change messes around with the amount of timing of 649 00:36:26,960 --> 00:36:30,399 Speaker 1: the rainfall on Christmas Island, and then the crabs get 650 00:36:30,400 --> 00:36:32,759 Speaker 1: the short end of the stick and could find themselves 651 00:36:32,840 --> 00:36:36,560 Speaker 1: unable to use their normal migration and breeding instincts in 652 00:36:36,640 --> 00:36:39,520 Speaker 1: order to produce the next generation. And this could also 653 00:36:39,520 --> 00:36:42,480 Speaker 1: have follow on effects with the animals that depend on 654 00:36:42,600 --> 00:36:46,000 Speaker 1: these migratory animals for food, like the Christmas Island red 655 00:36:46,040 --> 00:36:49,000 Speaker 1: crab is sort of a keystone species on the island 656 00:36:49,000 --> 00:36:51,720 Speaker 1: in many ways. One of the things we already mentioned 657 00:36:51,760 --> 00:36:54,480 Speaker 1: is that those whale sharks come to eat the Christmas 658 00:36:54,520 --> 00:36:57,480 Speaker 1: Island red crab larvae in the water. But another thing 659 00:36:57,600 --> 00:37:00,160 Speaker 1: is as we mentioned, they maintain the state of the 660 00:37:00,200 --> 00:37:04,400 Speaker 1: forest by clearing leaf litter and clearing out other plants 661 00:37:04,400 --> 00:37:07,520 Speaker 1: in the undergrowth of the forest and you know, and 662 00:37:07,560 --> 00:37:11,200 Speaker 1: by turning the soil right, Yeah, they're their aerators. Now, 663 00:37:11,320 --> 00:37:14,800 Speaker 1: there is another culprit that is putting the Christmas Island 664 00:37:14,800 --> 00:37:18,120 Speaker 1: red crabs at risk, and that is yellow crazy ants 665 00:37:18,480 --> 00:37:22,040 Speaker 1: crazy ants. Again, it's different crazy ants somewhat. So we 666 00:37:22,080 --> 00:37:24,560 Speaker 1: did an episode about crazy ants before, but that was 667 00:37:24,600 --> 00:37:27,279 Speaker 1: focused on a completely different animal. We were mainly talking 668 00:37:27,280 --> 00:37:31,080 Speaker 1: about the raspberry crazy ant of the genus Nylandria. The 669 00:37:31,160 --> 00:37:34,160 Speaker 1: yellow ant is a totally different genus. It's an apolo 670 00:37:34,280 --> 00:37:38,680 Speaker 1: Lepus gracillips and these are ants with a slender body, 671 00:37:39,000 --> 00:37:42,839 Speaker 1: long legs, and like the crazy ants in genus Nylandria, 672 00:37:42,880 --> 00:37:46,359 Speaker 1: they're also easily recognized by these movement patterns that give 673 00:37:46,400 --> 00:37:49,240 Speaker 1: them their name. Their motion is sometimes described as frantic 674 00:37:49,400 --> 00:37:53,319 Speaker 1: or erratic or crazy, and like raspberry crazy ants, these 675 00:37:53,360 --> 00:37:56,640 Speaker 1: ants can also form what are known as super colonies, 676 00:37:57,040 --> 00:38:01,040 Speaker 1: which means they build separate but friendly nests which do 677 00:38:01,120 --> 00:38:04,040 Speaker 1: not attack one another and form a kind of web 678 00:38:04,080 --> 00:38:07,880 Speaker 1: of allied ant armies that can easily overwhelm the habitats 679 00:38:07,960 --> 00:38:10,759 Speaker 1: that they spread to, and so they're considered a very 680 00:38:10,800 --> 00:38:15,120 Speaker 1: problematic invasive species. Like other crazy ants. Also, they spray 681 00:38:15,239 --> 00:38:19,560 Speaker 1: formic acid as a defensive and offensive biological weapon, and 682 00:38:19,600 --> 00:38:23,440 Speaker 1: formic acid is a powerful chemical. Uh, it's apparently a 683 00:38:23,520 --> 00:38:26,719 Speaker 1: potent poison against land crabs. So you can imagine a 684 00:38:26,760 --> 00:38:29,320 Speaker 1: bunch of ants come up against one of these Christmas 685 00:38:29,400 --> 00:38:32,560 Speaker 1: Island red crabs and the ants spray formic acid in 686 00:38:32,640 --> 00:38:36,239 Speaker 1: its eyes, in the segment joints of the crabs, so 687 00:38:36,360 --> 00:38:39,000 Speaker 1: you know, like getting in the leg joints, and this 688 00:38:39,040 --> 00:38:41,680 Speaker 1: can leave the crabs unable to move or to survive. 689 00:38:41,760 --> 00:38:43,920 Speaker 1: And then after the crabs die, of course, the ants 690 00:38:43,960 --> 00:38:46,080 Speaker 1: get a feast of crab meat. And this has had 691 00:38:46,120 --> 00:38:49,200 Speaker 1: a huge impact on crab populations. It's been estimated that 692 00:38:49,320 --> 00:38:52,319 Speaker 1: in the last fifteen years the ants have reduced the 693 00:38:52,360 --> 00:38:55,920 Speaker 1: crab populations on the island by as much as tykes. 694 00:38:56,200 --> 00:38:58,759 Speaker 1: So local land crabs have been put severely at risk 695 00:38:58,840 --> 00:39:03,040 Speaker 1: by the yellow crazy ants. Interestingly, the yellow crazy ants 696 00:39:03,160 --> 00:39:05,920 Speaker 1: existed on the island for many decades. I think they 697 00:39:05,960 --> 00:39:08,840 Speaker 1: were introduced sometime in the first half of the twentieth century. 698 00:39:08,840 --> 00:39:12,640 Speaker 1: I've seen estimates in the nineteen teens or twenties around then. Uh, 699 00:39:12,680 --> 00:39:15,680 Speaker 1: And they were on the island a long time before 700 00:39:15,840 --> 00:39:19,320 Speaker 1: they became so destructive to the land crabs beginning around 701 00:39:19,360 --> 00:39:23,680 Speaker 1: the nineteen nineties. So what changed around the nineteen nineties. 702 00:39:24,200 --> 00:39:27,120 Speaker 1: I was reading a report that was put together by 703 00:39:27,160 --> 00:39:31,239 Speaker 1: Parks Australia together with Latrobe University, and it appears that 704 00:39:31,320 --> 00:39:34,000 Speaker 1: it was only in the nineteen nineties or so that 705 00:39:34,040 --> 00:39:38,160 Speaker 1: these massive super colonies of yellow crazy ants began forming. 706 00:39:38,600 --> 00:39:42,120 Speaker 1: So what caused that change? What happened then? Uh? The 707 00:39:42,160 --> 00:39:45,719 Speaker 1: author's point to the emergence of a mutualism, actually a 708 00:39:45,800 --> 00:39:49,600 Speaker 1: symbiotic relationship, and this is a mutualism between the yellow 709 00:39:49,640 --> 00:39:53,879 Speaker 1: crazy ants and another group of insects called scale insects. 710 00:39:54,480 --> 00:39:57,280 Speaker 1: So it's like the like the two enemies, they they 711 00:39:57,400 --> 00:40:01,080 Speaker 1: forged a truce and and then we're united against the 712 00:40:01,160 --> 00:40:05,000 Speaker 1: forces of the crab. Yes, so another non native species, 713 00:40:05,040 --> 00:40:07,920 Speaker 1: the scale insects. What they do is they cling to 714 00:40:07,960 --> 00:40:11,440 Speaker 1: plant stems and they suck the sap from the plants 715 00:40:11,480 --> 00:40:14,960 Speaker 1: for energy, and they produce a sugary waste product from 716 00:40:15,000 --> 00:40:18,640 Speaker 1: their anal pores in the process. And the ants love 717 00:40:18,840 --> 00:40:21,680 Speaker 1: this sugary poop. They go straight to the anal pores 718 00:40:21,760 --> 00:40:23,960 Speaker 1: and they eat it up. So they have formed this 719 00:40:24,160 --> 00:40:29,040 Speaker 1: mutualistic protective relationship with the tree sucking candy poopers. The 720 00:40:29,080 --> 00:40:32,440 Speaker 1: scale insects suck from the trees, they produce sugary poop. 721 00:40:32,719 --> 00:40:35,480 Speaker 1: The yellow the yellow crazy ants eat the sugary poop 722 00:40:35,480 --> 00:40:38,759 Speaker 1: and they protect the scale insects. And it appears that 723 00:40:38,880 --> 00:40:42,160 Speaker 1: this emerging symbiosis between the yellow crazy ants and the 724 00:40:42,160 --> 00:40:46,040 Speaker 1: scale insects is related to the ant's ability to form 725 00:40:46,200 --> 00:40:51,080 Speaker 1: these ecologically devastating super colonies. But here's so, then you 726 00:40:51,120 --> 00:40:53,640 Speaker 1: take the question one step back, Well, what caused this 727 00:40:53,760 --> 00:40:56,880 Speaker 1: mutualism to begin in the first place. Uh, the authors 728 00:40:56,880 --> 00:41:00,200 Speaker 1: of this report don't know. They speculate that change ng 729 00:41:00,320 --> 00:41:04,120 Speaker 1: rainfall patterns on Christmas Island. We're putting stress on trees 730 00:41:04,680 --> 00:41:08,399 Speaker 1: and this made the sap more concentrated, which means it's 731 00:41:08,440 --> 00:41:11,799 Speaker 1: even more sugary goodness for the scale insects. And this 732 00:41:11,960 --> 00:41:16,319 Speaker 1: increases the population of the scale insects, which produces more 733 00:41:16,400 --> 00:41:19,600 Speaker 1: delicious sugary poop for their yellow ant friends, which means 734 00:41:19,640 --> 00:41:22,520 Speaker 1: more ants to protect the scale insects, which means even 735 00:41:22,600 --> 00:41:25,880 Speaker 1: more scale insects. And then you get this dangerous feedback loop. 736 00:41:26,600 --> 00:41:29,600 Speaker 1: It's this is all Christmas Island is in so many ways. 737 00:41:29,719 --> 00:41:35,200 Speaker 1: This Uh, this wonderful look at the horrible cascading effects 738 00:41:35,360 --> 00:41:38,480 Speaker 1: of colonialism, of human intervention in general, I mean at 739 00:41:38,480 --> 00:41:42,399 Speaker 1: the macroscopic climate level and at the local invasive level. Yeah, 740 00:41:42,960 --> 00:41:45,720 Speaker 1: like at every level. We have messed with this island, 741 00:41:46,040 --> 00:41:47,880 Speaker 1: and we messed it with it in one way, and 742 00:41:47,920 --> 00:41:50,120 Speaker 1: now we're messing with it in a different way, and 743 00:41:50,120 --> 00:41:52,160 Speaker 1: and now in fact we're gonna keep messing with it 744 00:41:52,200 --> 00:41:54,640 Speaker 1: in order to try to fix part of what we did. 745 00:41:55,840 --> 00:41:58,960 Speaker 1: Because the question is can anything be done to save 746 00:41:59,040 --> 00:42:02,160 Speaker 1: these amazing red crabs? I mean, these are It is 747 00:42:02,360 --> 00:42:05,200 Speaker 1: a wonderful thing to see these animals doing what they do. 748 00:42:05,560 --> 00:42:07,799 Speaker 1: And so I was reading an interesting article about this 749 00:42:07,880 --> 00:42:11,720 Speaker 1: on the Conversation in UH posted in by two Latrobe 750 00:42:11,800 --> 00:42:16,680 Speaker 1: University professors Susan Lawler and Peter Green, and apparently Parks 751 00:42:16,719 --> 00:42:19,400 Speaker 1: Australia has been trying to do all kinds of things 752 00:42:19,680 --> 00:42:22,120 Speaker 1: to help the crabs survive the crazy ants or to 753 00:42:22,200 --> 00:42:25,200 Speaker 1: knock the crazy ant super colonies back, like they tried 754 00:42:25,280 --> 00:42:27,920 Speaker 1: poison bading the ants by hand. But apparently this is 755 00:42:27,960 --> 00:42:31,600 Speaker 1: just not an efficient solution. In seen, they launched a 756 00:42:31,640 --> 00:42:34,960 Speaker 1: new project and this was Killer Wasps. I like it 757 00:42:35,040 --> 00:42:37,600 Speaker 1: tell me more so, the Killer Wasps they're only about 758 00:42:37,600 --> 00:42:40,840 Speaker 1: two millimeters long, and they're naturally found in India and 759 00:42:40,920 --> 00:42:45,799 Speaker 1: Southeast Asia. They're called tach Cardia vegas Summerville and the 760 00:42:45,840 --> 00:42:50,320 Speaker 1: author selected this tiny wasp because it attacks this specific 761 00:42:50,440 --> 00:42:54,799 Speaker 1: species of scale insect that has formed the mutualistic relationship 762 00:42:55,000 --> 00:42:59,320 Speaker 1: with the crazy ants uh so. And the wasp is 763 00:42:59,360 --> 00:43:02,680 Speaker 1: a parasite oid that lays its eggs in the body 764 00:43:02,800 --> 00:43:05,680 Speaker 1: of the female of this one species of scale insect, 765 00:43:06,080 --> 00:43:09,120 Speaker 1: which hatch into more wasps that lay more eggs in 766 00:43:09,160 --> 00:43:13,280 Speaker 1: these species of scale insects, and hopefully this will severely 767 00:43:13,360 --> 00:43:17,800 Speaker 1: control the population of this one particular species of scale insect, 768 00:43:17,840 --> 00:43:20,680 Speaker 1: which is also invasive on the island. Uh And the 769 00:43:20,719 --> 00:43:23,239 Speaker 1: author's note that they've had to be very cautious because 770 00:43:23,280 --> 00:43:26,600 Speaker 1: they cite examples that, you know, in the past, we've 771 00:43:26,640 --> 00:43:30,000 Speaker 1: tried to introduce animals to places in the hope that 772 00:43:30,040 --> 00:43:32,640 Speaker 1: they would control the pest problem, but then they became 773 00:43:32,680 --> 00:43:34,680 Speaker 1: a problem in their own right. They said, the example 774 00:43:34,719 --> 00:43:37,520 Speaker 1: of the cane toad in Australia, which was brought into 775 00:43:37,560 --> 00:43:40,239 Speaker 1: control cane beetles, but then it became its own kind 776 00:43:40,239 --> 00:43:44,000 Speaker 1: of problem. And I'm reminded, of course, of the old 777 00:43:44,080 --> 00:43:45,920 Speaker 1: nursery rhyme. There was an old lady who swallowed a 778 00:43:45,960 --> 00:43:50,160 Speaker 1: fly right, and she's forced to keep swallowing progressively larger 779 00:43:50,239 --> 00:43:54,200 Speaker 1: and parasitic wasps and larger and more destructive organisms to 780 00:43:54,239 --> 00:43:56,719 Speaker 1: try and uh savor until if she dies at the 781 00:43:56,760 --> 00:43:59,719 Speaker 1: end of the song. Well, the authors, so we hope 782 00:43:59,719 --> 00:44:04,080 Speaker 1: that that happened. The authors claimed they performed rigorous research beforehand. 783 00:44:04,520 --> 00:44:06,960 Speaker 1: Uh they tested really hard to make sure this wasp 784 00:44:07,000 --> 00:44:10,480 Speaker 1: would not harm other local species. And they said, you know, 785 00:44:10,520 --> 00:44:13,000 Speaker 1: according to their tests, everything seemed to check out. So 786 00:44:13,040 --> 00:44:16,680 Speaker 1: they introduced the wasps in sixteen, and I checked with 787 00:44:16,719 --> 00:44:19,480 Speaker 1: a more recent news article on the wasp control project 788 00:44:19,480 --> 00:44:22,840 Speaker 1: from it looks like the effort is having early markers 789 00:44:22,880 --> 00:44:26,640 Speaker 1: for success. The wasps have become established, their range is spreading. 790 00:44:27,360 --> 00:44:29,239 Speaker 1: But we'll have to wait a few more years before 791 00:44:29,280 --> 00:44:31,680 Speaker 1: we see the full effect on the crab populations. But 792 00:44:31,960 --> 00:44:33,640 Speaker 1: I hope it works, and I hope it doesn't have 793 00:44:33,680 --> 00:44:37,120 Speaker 1: any unexpected effects. Less to become Island of the wasps, 794 00:44:37,280 --> 00:44:39,600 Speaker 1: Kingdom of the wasps. You don't want to have to 795 00:44:39,640 --> 00:44:43,120 Speaker 1: think about Crab Island needing to be protected. You want 796 00:44:43,120 --> 00:44:47,239 Speaker 1: to think that Crab Island is an armored claw wielding 797 00:44:47,760 --> 00:44:50,279 Speaker 1: force to be reckoned with, and that it you know, 798 00:44:50,400 --> 00:44:54,000 Speaker 1: it can withstand anything on its own. But I don't know. Yeah, 799 00:44:54,120 --> 00:44:58,200 Speaker 1: natural populations or even unnatural populations are vulnerable. Yeah, I 800 00:44:58,200 --> 00:45:01,839 Speaker 1: mean look at Skull Island right King Kong's homeland. Oh, 801 00:45:01,840 --> 00:45:04,560 Speaker 1: I don't know anything about population dynamics there. Or a 802 00:45:04,680 --> 00:45:09,840 Speaker 1: monster Island where all the giant Japanese monsters with kaiju. 803 00:45:10,600 --> 00:45:13,440 Speaker 1: That's clearly these are places that need to be protected. 804 00:45:13,440 --> 00:45:14,880 Speaker 1: We don't need to go in there and try and 805 00:45:14,880 --> 00:45:17,200 Speaker 1: to feed them with our robots. Is there is there 806 00:45:17,200 --> 00:45:21,080 Speaker 1: a crab kaju? Yes, there are. There are crab kaiju 807 00:45:21,320 --> 00:45:24,160 Speaker 1: up the wazoo. Yes, nice. Yes, they have their own 808 00:45:24,239 --> 00:45:27,839 Speaker 1: movies sometimes. Yeah, Godzillafa. Want to forget its name? I can. 809 00:45:27,960 --> 00:45:33,840 Speaker 1: I can never remember the names of the adversary that 810 00:45:34,080 --> 00:45:36,040 Speaker 1: maybe it. But yeah, he found a giant crab in 811 00:45:36,080 --> 00:45:38,600 Speaker 1: one episode. It was I finally remember it from my childhood. 812 00:45:38,719 --> 00:45:40,880 Speaker 1: But we'll get into we'll get into monster crabs a 813 00:45:40,880 --> 00:45:43,560 Speaker 1: bit more in the next episode of Stuff to Blow 814 00:45:43,600 --> 00:45:46,520 Speaker 1: your Mind, because we will talk about another resident of 815 00:45:47,080 --> 00:45:50,799 Speaker 1: Christmas Island that is an enormous deco pod. In fact, 816 00:45:50,800 --> 00:45:54,359 Speaker 1: that the largest land crab that you will find on 817 00:45:54,480 --> 00:45:57,480 Speaker 1: Earth now naturally, would love to hear from everybody out there. 818 00:45:57,520 --> 00:46:00,680 Speaker 1: We have listeners all over the world. I wonder if 819 00:46:00,719 --> 00:46:04,800 Speaker 1: we have just a single listener that lives on Christmas Island, 820 00:46:05,880 --> 00:46:09,000 Speaker 1: if we do email us yes, Likewise, we have a 821 00:46:09,000 --> 00:46:11,839 Speaker 1: lot of Australian and listeners UH and just listeners who 822 00:46:12,000 --> 00:46:14,319 Speaker 1: have traveled around the world in general. If you have 823 00:46:14,480 --> 00:46:18,040 Speaker 1: ever been to Christmas Island and witnessed any of the 824 00:46:18,040 --> 00:46:20,400 Speaker 1: species we discussed here, or just I mean even if 825 00:46:20,400 --> 00:46:23,000 Speaker 1: you've just been there and you saw nothing at all, 826 00:46:23,040 --> 00:46:25,120 Speaker 1: We want to hear from you. Whatever you have to 827 00:46:25,120 --> 00:46:28,480 Speaker 1: share about Christmas Island would be gratefully appreciated. And in 828 00:46:28,480 --> 00:46:30,200 Speaker 1: the meantime, you can check out all the episodes of 829 00:46:30,200 --> 00:46:31,879 Speaker 1: Stuff to Blow Your Mind. It's stuff to Blow your 830 00:46:31,880 --> 00:46:34,799 Speaker 1: Mind dot com. That's where you'll find all the episodes. 831 00:46:35,000 --> 00:46:38,600 Speaker 1: Links out to our various social media accounts, including UH 832 00:46:38,200 --> 00:46:42,360 Speaker 1: the discussion the module, which is our group on Facebook. 833 00:46:42,400 --> 00:46:44,279 Speaker 1: Look up stuff to Blow your Mind Discussion module and 834 00:46:44,320 --> 00:46:47,840 Speaker 1: you can easily join that and interact with other listeners 835 00:46:47,840 --> 00:46:51,480 Speaker 1: as as as well as Joe and myself. The website 836 00:46:51,520 --> 00:46:53,520 Speaker 1: Stuff to Blow your Mind dot com also has a 837 00:46:53,560 --> 00:46:55,560 Speaker 1: link to our store where you can buy some cool 838 00:46:55,600 --> 00:47:00,520 Speaker 1: merchandise stickers, shirts, etcetera. Um, it's probably probably a bit 839 00:47:00,560 --> 00:47:03,640 Speaker 1: late now for for Christmas gifts, at least for this Christmas, 840 00:47:03,680 --> 00:47:05,960 Speaker 1: but hey, you can go ahead and start start banking 841 00:47:06,000 --> 00:47:08,080 Speaker 1: ahead for next year. It's a great way to support 842 00:47:08,080 --> 00:47:09,680 Speaker 1: the show. 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If you would like to get 847 00:47:21,480 --> 00:47:23,640 Speaker 1: in touch with us directly to let us know feedback 848 00:47:23,680 --> 00:47:26,239 Speaker 1: on this episode or any other, to suggest topic for 849 00:47:26,280 --> 00:47:28,120 Speaker 1: the future, or just to say hi, let us know 850 00:47:28,120 --> 00:47:30,160 Speaker 1: where you listen from that kind of thing, you can 851 00:47:30,200 --> 00:47:33,120 Speaker 1: email us at blow the Mind at how stuff works 852 00:47:33,280 --> 00:47:44,880 Speaker 1: dot com for moral this and thousands of other topics. 853 00:47:45,000 --> 00:48:03,800 Speaker 1: Does it how stuff works dot com, theddutory bar, proper 854 00:48:05,520 --> 00:48:05,640 Speaker 1: par