1 00:00:01,602 --> 00:00:04,303 Narrator: Ever wondered why an apex predator 2 00:00:04,305 --> 00:00:07,006 Would let this guy escape? 3 00:00:07,008 --> 00:00:09,708 So this is very bizarre behavior. 4 00:00:09,710 --> 00:00:12,978 Narrator: What could cause this ominous, dark mass? 5 00:00:12,980 --> 00:00:17,449 So, it looks as though there's this apocalyptic cloud. 6 00:00:17,451 --> 00:00:19,351 Narrator: And why scorpions can light up 7 00:00:19,353 --> 00:00:21,487 Like a las vegas nightclub? 8 00:00:21,489 --> 00:00:23,922 So this is just a mad scene. 9 00:00:23,924 --> 00:00:25,724 ♪ 10 00:00:25,726 --> 00:00:28,460 Narrator: Nature is awe-inspiring. 11 00:00:28,462 --> 00:00:31,130 But sometimes it just doesn't make sense. 12 00:00:31,132 --> 00:00:33,565 Man: I have never seen anything like this. 13 00:00:33,567 --> 00:00:37,202 Narrator: Our team of experts investigate the weirdest animal behavior... 14 00:00:37,204 --> 00:00:38,303 That's amazing. 15 00:00:38,305 --> 00:00:40,072 ...And the most unexpected events... 16 00:00:40,074 --> 00:00:41,607 What is causing that? 17 00:00:41,609 --> 00:00:43,108 ...Ever caught on camera. 18 00:00:43,110 --> 00:00:44,610 Woman: My god! 19 00:00:44,612 --> 00:00:46,578 These are... 20 00:00:48,382 --> 00:00:51,216 -- Captions by vitac -- www.Vitac.Com 21 00:00:51,218 --> 00:00:54,053 Captions paid for by discovery communications 22 00:00:54,055 --> 00:00:57,623 Narrator: Londolozi, south africa. 23 00:00:57,625 --> 00:01:01,960 A safari guide captures a dramatic scene. 24 00:01:01,962 --> 00:01:04,997 A civet -- a small, cat-like mammal -- 25 00:01:04,999 --> 00:01:07,433 Cowers in the middle of a puddle. 26 00:01:07,435 --> 00:01:10,302 Why is it so scared? 27 00:01:10,304 --> 00:01:13,772 Because it's being eyeballed by an enormous leopard. 28 00:01:13,774 --> 00:01:16,375 ♪ 29 00:01:16,377 --> 00:01:18,911 It's a case of "wrong time, wrong place" 30 00:01:18,913 --> 00:01:21,613 For this normally nocturnal critter. 31 00:01:21,615 --> 00:01:23,782 The question is, what will it do? 32 00:01:23,784 --> 00:01:25,584 ♪ 33 00:01:25,586 --> 00:01:28,787 So, it's a really tense bit of footage. 34 00:01:28,789 --> 00:01:32,157 Narrator: The leopard slowly circles the water. 35 00:01:32,159 --> 00:01:34,193 But then... 36 00:01:34,195 --> 00:01:38,330 [ whimsical music plays ] 37 00:01:38,332 --> 00:01:40,833 ...Flops down to sleep. 38 00:01:40,835 --> 00:01:43,502 So, why hasn't she launched an attack? 39 00:01:43,504 --> 00:01:45,471 ♪ 40 00:01:45,473 --> 00:01:48,073 Narrator: Is she the laziest leopard in the world? 41 00:01:48,075 --> 00:01:49,708 Lunch is right there. 42 00:01:49,710 --> 00:01:52,478 There's no chance that that leopard can't see the civet. 43 00:01:52,480 --> 00:01:55,781 The civet's stopped moving, therefore is invisible. 44 00:01:55,783 --> 00:01:58,283 We're not talking about "jurassic park" dinosaurs here. 45 00:01:58,285 --> 00:01:59,718 Schreiber: These are nocturnal hunters. 46 00:01:59,720 --> 00:02:02,321 They have incredible eyesight, they have incredible smell. 47 00:02:02,323 --> 00:02:04,823 There is no way that she has just walked past the puddle 48 00:02:04,825 --> 00:02:07,192 And not noticed a living civet inside of it. 49 00:02:07,194 --> 00:02:08,961 [ beeps ] 50 00:02:08,963 --> 00:02:12,898 Narrator: So, what's going on? 51 00:02:12,900 --> 00:02:14,233 ♪ 52 00:02:14,235 --> 00:02:17,469 Maybe this leopard does not like hunting in water. 53 00:02:17,471 --> 00:02:21,006 Burke: This leopard looks really reluctant to get its paws wet, 54 00:02:21,008 --> 00:02:22,741 And, of course, cats are quite famous 55 00:02:22,743 --> 00:02:24,710 For not really liking the water. 56 00:02:24,712 --> 00:02:26,445 Narrator: But that's domestic cats. 57 00:02:26,447 --> 00:02:28,013 [ shrieks ] big cats, 58 00:02:28,015 --> 00:02:30,616 Like this jaguar, are a bit different. 59 00:02:30,618 --> 00:02:32,184 I've seen jaguar hunting in the water. 60 00:02:32,186 --> 00:02:34,419 I've seen jaguar hunting caiman, which is a kind of, 61 00:02:34,421 --> 00:02:36,054 You know, crocodile, basically. 62 00:02:36,056 --> 00:02:38,824 ♪ 63 00:02:38,826 --> 00:02:40,559 Tigers are famous for it as well. 64 00:02:40,561 --> 00:02:42,327 You know, they'll quite happily swim and wallow. 65 00:02:42,329 --> 00:02:44,796 ♪ 66 00:02:44,798 --> 00:02:48,867 Narrator: And certain leopards actively hunt fish for dinner. 67 00:02:48,869 --> 00:02:50,802 In botswana, there's a population 68 00:02:50,804 --> 00:02:52,604 In an area called savuti where the leopards 69 00:02:52,606 --> 00:02:55,507 Have really specialized in hunting in the water. 70 00:02:55,509 --> 00:02:57,242 They actually hunt catfish. 71 00:02:57,244 --> 00:03:00,345 Narrator: So a puddle this size wouldn't stop a leopard. 72 00:03:00,347 --> 00:03:04,016 I think if it wanted that civet, it would have it. 73 00:03:04,018 --> 00:03:06,919 I think there's other things at play here. 74 00:03:06,921 --> 00:03:10,022 Narrator: Could there be a clue in the civet's stance? 75 00:03:10,024 --> 00:03:13,725 He's standing hair on end to look as big as possible. 76 00:03:13,727 --> 00:03:16,595 ♪ 77 00:03:16,597 --> 00:03:19,231 [ beeps ] 78 00:03:19,233 --> 00:03:21,700 Has acting tough saved him? 79 00:03:21,702 --> 00:03:23,268 ♪ 80 00:03:23,270 --> 00:03:25,537 When a predator's coming after you, 81 00:03:25,539 --> 00:03:29,308 Feistiness can be a secret weapon -- 82 00:03:29,310 --> 00:03:32,377 Like these river otters that successfully ganged up 83 00:03:32,379 --> 00:03:35,814 To see off a lurking crocodile. 84 00:03:35,816 --> 00:03:38,584 But the crocodile was outnumbered. 85 00:03:38,586 --> 00:03:40,552 So is there more going on here 86 00:03:40,554 --> 00:03:43,689 Than just a civet standing up for itself? 87 00:03:43,691 --> 00:03:45,490 [ beeps ] 88 00:03:45,492 --> 00:03:48,994 Could it be that the civet just isn't that appetizing? 89 00:03:51,365 --> 00:03:54,266 Civets are know for one thing in particular -- 90 00:03:54,268 --> 00:03:56,401 Civets are famously smelly animals. 91 00:03:56,403 --> 00:03:58,637 They have massive anal glands, 92 00:03:58,639 --> 00:04:02,074 And they produce this sort of oily, musky secretion, 93 00:04:02,076 --> 00:04:04,009 Which is not particularly nice. 94 00:04:04,011 --> 00:04:06,078 So you've got to be pretty hungry, 95 00:04:06,080 --> 00:04:09,815 I'd imagine, to be a leopard to bother with a civet. 96 00:04:09,817 --> 00:04:11,750 They've probably encountered a civet in the past, 97 00:04:11,752 --> 00:04:13,018 And you don't really want your dinner 98 00:04:13,020 --> 00:04:14,853 Scratching your face as you're eating it. 99 00:04:14,855 --> 00:04:19,224 Narrator: Is this civet just not worth the effort? 100 00:04:19,226 --> 00:04:20,993 As the footage unfolds, 101 00:04:20,995 --> 00:04:23,195 Another leopard enters the picture. 102 00:04:23,197 --> 00:04:26,398 ♪ 103 00:04:26,400 --> 00:04:30,035 This male comes on the scene. 104 00:04:30,037 --> 00:04:32,471 We start to realize that maybe she's distracted 105 00:04:32,473 --> 00:04:34,273 By something else. 106 00:04:34,275 --> 00:04:36,108 Narrator: Are they more interested in each other 107 00:04:36,110 --> 00:04:37,442 Than in food? 108 00:04:39,980 --> 00:04:41,847 Now, leopards are solitary animals. 109 00:04:41,849 --> 00:04:44,249 They don't spend a lot of time together. 110 00:04:44,251 --> 00:04:46,618 Narrator: Even when hunting, they go it alone. 111 00:04:46,620 --> 00:04:48,387 ♪ 112 00:04:48,389 --> 00:04:51,056 But when it's time for business, 113 00:04:51,058 --> 00:04:53,425 A pair will stick together for days 114 00:04:53,427 --> 00:04:56,261 And mate up to 100 times in 24 hours. 115 00:04:56,263 --> 00:04:57,896 [ laughs ] 116 00:04:57,898 --> 00:05:00,832 ♪ 117 00:05:00,834 --> 00:05:02,968 Burke: So as this male joins the female, 118 00:05:02,970 --> 00:05:05,070 They clearly have something else on their mind. 119 00:05:05,072 --> 00:05:08,240 Narrator: Something else, but not necessarily mating. 120 00:05:08,242 --> 00:05:10,475 ♪ 121 00:05:10,477 --> 00:05:12,744 Burke: There's a lot of tension. They have a little scuffle. 122 00:05:12,746 --> 00:05:15,914 [ grunting ] 123 00:05:15,916 --> 00:05:18,250 Narrator: And they bolt straight up the marula tree. 124 00:05:18,252 --> 00:05:21,520 [ growling continues ] 125 00:05:21,522 --> 00:05:23,789 Another clue, right there in the footage, 126 00:05:23,791 --> 00:05:25,757 Reveals what they're fighting over 127 00:05:25,759 --> 00:05:29,928 And why they've ignored the civet. 128 00:05:29,930 --> 00:05:32,664 This video clip turns from a curious bit of behavior, 129 00:05:32,666 --> 00:05:34,800 Or a curious lack of behavior, 130 00:05:34,802 --> 00:05:37,636 To when the second leopard turns up. 131 00:05:37,638 --> 00:05:41,273 And then as it climbs up that marula tree in the background... 132 00:05:41,275 --> 00:05:43,475 [ growling ] 133 00:05:43,477 --> 00:05:45,177 ...At the top of it is probably a key part 134 00:05:45,179 --> 00:05:47,145 Of this whole story. 135 00:05:47,147 --> 00:05:50,382 Narrator: The civet would just be a starter anyway. 136 00:05:50,384 --> 00:05:52,584 It seems the leopards have already stashed 137 00:05:52,586 --> 00:05:56,154 Their main course up in the tree. 138 00:05:56,156 --> 00:05:59,624 Baker: The remains of a kudu carcass -- this is a massive antelope. 139 00:05:59,626 --> 00:06:02,694 So this leopard isn't short of food. 140 00:06:02,696 --> 00:06:08,367 So why eat a civet when you got a belly fully of prime venison? 141 00:06:08,369 --> 00:06:10,402 Burke: So that's the reason why the civet isn't really 142 00:06:10,404 --> 00:06:12,270 That interesting to these leopards -- 143 00:06:12,272 --> 00:06:15,374 Because they already have something to eat. 144 00:06:15,376 --> 00:06:17,275 Narrator: Keeping a treetop pantry 145 00:06:17,277 --> 00:06:20,178 Is standard practice for leopards. 146 00:06:20,180 --> 00:06:22,681 Baker: Why bother drag a kudu carcass to the top of a tree 147 00:06:22,683 --> 00:06:24,182 Is that this is africa. 148 00:06:24,184 --> 00:06:27,886 It's full of other animals that will steal your carcass. 149 00:06:27,888 --> 00:06:31,390 Hyenas in particular will easily steal from a leopard, 150 00:06:31,392 --> 00:06:33,258 So they just want to get that up 151 00:06:33,260 --> 00:06:35,761 And out of the way of animals that can't climb. 152 00:06:35,763 --> 00:06:40,098 ♪ 153 00:06:40,100 --> 00:06:44,936 [ birds and insects chirping ] 154 00:06:44,938 --> 00:06:46,171 ♪ 155 00:06:46,173 --> 00:06:49,875 Narrator: Phoenix, arizona, summer 2018. 156 00:06:49,877 --> 00:06:52,377 As night falls, a pest-control team 157 00:06:52,379 --> 00:06:55,147 Are sweeping homes and gardens. 158 00:06:55,149 --> 00:06:57,349 They've been called in by worried homeowners 159 00:06:57,351 --> 00:06:59,951 To look for venomous scorpions. 160 00:06:59,953 --> 00:07:03,422 You know, the most we've ever caught in a home is about 280. 161 00:07:03,424 --> 00:07:05,257 Our average is 12 per sweep. 162 00:07:05,259 --> 00:07:06,691 Gaffin: How dangerous are scorpions? 163 00:07:06,693 --> 00:07:09,161 Well, the scorpions from south arizona, 164 00:07:09,163 --> 00:07:11,897 The arizona bark scorpion, are pretty dangerous. 165 00:07:11,899 --> 00:07:14,032 Globally, I think it's about 166 00:07:14,034 --> 00:07:17,736 1.2 million stings per year from scorpions. 167 00:07:17,738 --> 00:07:19,571 Narrator: Why hunt them at night? 168 00:07:19,573 --> 00:07:23,842 Well, during the day they're camouflaged and hard to spot. 169 00:07:23,844 --> 00:07:27,779 But at night under black light, also known as u.V., 170 00:07:27,781 --> 00:07:30,382 They give themselves away. 171 00:07:30,384 --> 00:07:32,851 They glow. Holland: Here we go. 172 00:07:32,853 --> 00:07:35,020 These are arizona bark scorpions, 173 00:07:35,022 --> 00:07:38,156 Which are the most venomous here in the united states. 174 00:07:38,158 --> 00:07:40,125 ♪ 175 00:07:40,127 --> 00:07:41,760 They have little hooks on the bottom of their feet 176 00:07:41,762 --> 00:07:43,061 That will grip onto texture, 177 00:07:43,063 --> 00:07:45,263 Much like velcro hooks into the loops, 178 00:07:45,265 --> 00:07:46,932 Which is how they get on people's walls 179 00:07:46,934 --> 00:07:48,400 And in people's houses. 180 00:07:48,402 --> 00:07:50,035 You can see that they glow rather well 181 00:07:50,037 --> 00:07:51,803 Under this ultraviolet light. 182 00:07:51,805 --> 00:07:54,272 ♪ 183 00:07:54,274 --> 00:07:57,943 Daly: There are over 2,000 known species of scorpions, 184 00:07:57,945 --> 00:08:01,313 Almost all of which are thought to glow under u.V. Light. 185 00:08:01,315 --> 00:08:05,450 ♪ 186 00:08:05,452 --> 00:08:08,386 Greive: One of the great, vexing questions for entomologists 187 00:08:08,388 --> 00:08:13,959 Is, "why do scorpions glow under ultraviolet light?" 188 00:08:13,961 --> 00:08:17,395 Narrator: It's puzzled scientists for decades. 189 00:08:17,397 --> 00:08:22,234 To try and figure out why, first we need to understand how. 190 00:08:22,236 --> 00:08:24,302 Scorpions have this wicked trick 191 00:08:24,304 --> 00:08:27,072 Where they take light in at one wavelength, 192 00:08:27,074 --> 00:08:29,140 And then put it out at a different wavelength. 193 00:08:29,142 --> 00:08:32,010 It's called fluorescence. 194 00:08:32,012 --> 00:08:34,713 Gaffin: In their outer layer of their skin, 195 00:08:34,715 --> 00:08:37,048 There's a couple of chemicals, 196 00:08:37,050 --> 00:08:41,419 And when ultraviolet light stimulates these molecules, 197 00:08:41,421 --> 00:08:44,689 They emit the fluorescence that we see. 198 00:08:44,691 --> 00:08:47,192 If you want to see fluorescence in a scorpion, 199 00:08:47,194 --> 00:08:49,794 It has to be ultraviolet light. 200 00:08:49,796 --> 00:08:53,198 Greive: The key to a scorpion's ability to glow under ultraviolet light 201 00:08:53,200 --> 00:08:58,169 Is contained in this very hard coating over the entire animal. 202 00:08:58,171 --> 00:09:00,939 The actual chemical that enables scorpions to glow, 203 00:09:00,941 --> 00:09:02,541 It's called carboline, 204 00:09:02,543 --> 00:09:07,345 And this has been true for millions and millions of years. 205 00:09:07,347 --> 00:09:09,581 Scorpions have been around for a very long time. 206 00:09:09,583 --> 00:09:11,850 In fact, there are fossil scorpions 207 00:09:11,852 --> 00:09:14,386 That are, like, this big. 208 00:09:14,388 --> 00:09:16,254 Narrator: The carboline in scorpion skin 209 00:09:16,256 --> 00:09:18,990 Is a u.V.-Absorbing chemical. 210 00:09:18,992 --> 00:09:22,727 In other animals, similar chemicals act as sunscreen. 211 00:09:22,729 --> 00:09:26,531 [ insects chirping ] 212 00:09:26,533 --> 00:09:27,899 [ beeps ] 213 00:09:27,901 --> 00:09:30,302 Could the same be true for scorpions? 214 00:09:30,304 --> 00:09:33,338 ♪ 215 00:09:33,340 --> 00:09:35,073 Now, this would make sense, 216 00:09:35,075 --> 00:09:37,442 Because way back in evolutionary history 217 00:09:37,444 --> 00:09:40,579 Scorpions may well have been active during the day. 218 00:09:40,581 --> 00:09:42,480 Narrator: So it's possible that the carboline 219 00:09:42,482 --> 00:09:44,883 That made scorpion ancestors glow 220 00:09:44,885 --> 00:09:48,386 Also acted as prehistoric sunscreen. 221 00:09:48,388 --> 00:09:49,921 Greive: So could it be performing 222 00:09:49,923 --> 00:09:53,925 That same function for scorpions today? 223 00:09:53,927 --> 00:09:57,729 Narrator: Maybe, apart from one little hitch. 224 00:09:57,731 --> 00:10:00,165 [ insects chirping ] 225 00:10:06,873 --> 00:10:10,375 [ insects chirping ] 226 00:10:10,377 --> 00:10:14,012 Narrator: In phoenix, arizona, and, in fact, across the world, 227 00:10:14,014 --> 00:10:16,247 Scorpions give up their hiding places 228 00:10:16,249 --> 00:10:19,117 By glowing under u.V. Light. 229 00:10:19,119 --> 00:10:22,554 The chemical that made ancient scorpion ancestors glow 230 00:10:22,556 --> 00:10:25,824 Probably acted as a form of sunscreen. 231 00:10:25,826 --> 00:10:28,526 Is that why scorpions glow today? 232 00:10:30,530 --> 00:10:34,566 Sounds plausible, apart from one small detail. 233 00:10:34,568 --> 00:10:36,701 Today's animals are much smaller 234 00:10:36,703 --> 00:10:39,137 And are almost exclusively nocturnal. 235 00:10:39,139 --> 00:10:40,705 [ insects chirping ] 236 00:10:40,707 --> 00:10:43,775 Narrator: Scorpions are most active just after sunset, 237 00:10:43,777 --> 00:10:46,611 So have no need for sunblock. 238 00:10:46,613 --> 00:10:48,079 Burke: And it wouldn't make sense for them 239 00:10:48,081 --> 00:10:51,816 To keep producing a chemical in their exoskeleton 240 00:10:51,818 --> 00:10:53,151 That is no longer needed. 241 00:10:53,153 --> 00:10:54,819 It just wouldn't make any anagenetic sense, 242 00:10:54,821 --> 00:10:57,389 So I don't think that's the answer. 243 00:10:57,391 --> 00:10:59,891 Narrator: If the chemical is not acting as sunblock, 244 00:10:59,893 --> 00:11:01,926 What is it for? 245 00:11:01,928 --> 00:11:03,628 [ beeps ] 246 00:11:03,630 --> 00:11:05,363 Could it be the scorpions glow 247 00:11:05,365 --> 00:11:09,167 To send each other messages instead? 248 00:11:09,169 --> 00:11:12,203 Are scorpions using this glowing ability 249 00:11:12,205 --> 00:11:14,673 To communicate with other scorpions, 250 00:11:14,675 --> 00:11:19,844 Either to define territories or to repel rivals? 251 00:11:19,846 --> 00:11:21,379 Daly: This isn't completely unlikely. 252 00:11:21,381 --> 00:11:23,815 Fluorescence has been used to communicate 253 00:11:23,817 --> 00:11:25,250 In other species, too. 254 00:11:25,252 --> 00:11:28,186 A study was done on the skulls of chameleons 255 00:11:28,188 --> 00:11:30,355 Where they have these florescent patterns, 256 00:11:30,357 --> 00:11:32,157 Which can help other chameleons 257 00:11:32,159 --> 00:11:36,361 Identify one another in a dark environment. 258 00:11:36,363 --> 00:11:39,097 Narrator: It's not out of the question that a scorpion's glow 259 00:11:39,099 --> 00:11:42,267 Could be for communication, just like the chameleon's. 260 00:11:43,270 --> 00:11:45,036 ♪ 261 00:11:45,038 --> 00:11:49,174 So what about glowing as a lonely hearts ad? 262 00:11:49,176 --> 00:11:50,375 I wouldn't rule this one out. 263 00:11:50,377 --> 00:11:53,244 I think there is a chance that perhaps males 264 00:11:53,246 --> 00:11:55,480 Might be detecting females from a distance. 265 00:11:55,482 --> 00:11:57,582 ♪ 266 00:11:57,584 --> 00:12:00,485 Narrator: A faintly glowing female could be like a beacon 267 00:12:00,487 --> 00:12:02,454 To a male scorpion. 268 00:12:02,456 --> 00:12:05,356 That's a "maybe" then to passionate scorpions 269 00:12:05,358 --> 00:12:08,059 Glowing for love. 270 00:12:08,061 --> 00:12:10,895 Professor douglas gaffin has been studying scorpions 271 00:12:10,897 --> 00:12:13,031 For 25 years. 272 00:12:13,033 --> 00:12:15,934 He thinks their glow could be multipurpose, 273 00:12:15,936 --> 00:12:19,237 But that it's most likely for keeping them save. 274 00:12:19,239 --> 00:12:23,241 Perhaps they are using the light as detected through their body 275 00:12:23,243 --> 00:12:26,044 To seek out places to hide for protection. 276 00:12:26,046 --> 00:12:27,779 [ beeps ] 277 00:12:27,781 --> 00:12:30,215 Narrator: Hang on. For protection? 278 00:12:30,217 --> 00:12:32,283 These are scorpions we're talking about -- 279 00:12:32,285 --> 00:12:36,955 Fierce, tail-bending stinger demons. 280 00:12:36,957 --> 00:12:39,657 They've got some amazing seismic detectors 281 00:12:39,659 --> 00:12:41,659 On each of the eight legs. 282 00:12:41,661 --> 00:12:43,895 ♪ 283 00:12:43,897 --> 00:12:47,766 They actually detect vibrations of the crickets as they walk by. 284 00:12:47,768 --> 00:12:49,267 Riskin: They've got pincers, 285 00:12:49,269 --> 00:12:51,503 But those are just sort of for keeping you at bay. 286 00:12:51,505 --> 00:12:53,204 The real business end is at the back. 287 00:12:53,206 --> 00:12:55,039 ♪ 288 00:12:55,041 --> 00:12:56,608 If the scorpion feels threatened, 289 00:12:56,610 --> 00:12:58,176 It can bring its tail down 290 00:12:58,178 --> 00:13:02,380 And whack you and inject venom very quickly. 291 00:13:02,382 --> 00:13:06,918 ♪ 292 00:13:06,920 --> 00:13:10,121 Narrator: You have to be brave to face down a scorpion. 293 00:13:10,123 --> 00:13:13,057 But some animals, like this bat-eared fox, 294 00:13:13,059 --> 00:13:15,894 Will take on the challenge. 295 00:13:15,896 --> 00:13:17,529 You see, scorpions are quite exposed 296 00:13:17,531 --> 00:13:18,830 When they're out there on the sand. 297 00:13:18,832 --> 00:13:20,965 There are predators of scorpions. 298 00:13:20,967 --> 00:13:23,968 ♪ 299 00:13:23,970 --> 00:13:27,572 Narrator: Scorpions are packed to the rafters with fancy features, 300 00:13:27,574 --> 00:13:30,308 But they have an achilles' heel. 301 00:13:30,310 --> 00:13:32,911 Scorpions don't have very good eyesight at all, 302 00:13:32,913 --> 00:13:35,680 So when they're running to hide, they need another mechanism 303 00:13:35,682 --> 00:13:39,384 To help them know whether they're hiding effectively. 304 00:13:39,386 --> 00:13:43,988 Narrator: Could their incredible glow be a tool to help them stay alive? 305 00:13:43,990 --> 00:13:45,523 ♪ 306 00:13:45,525 --> 00:13:47,892 [ insects chirping ] 307 00:13:54,501 --> 00:13:56,167 [ insects chirping ] 308 00:13:56,169 --> 00:13:57,468 ♪ 309 00:13:57,470 --> 00:13:59,037 Narrator: In phoenix, arizona, 310 00:13:59,039 --> 00:14:00,638 We're unraveling the secrets 311 00:14:00,640 --> 00:14:04,742 Of why scorpions glow under ultraviolet light. 312 00:14:04,744 --> 00:14:08,179 Could it be for protection? 313 00:14:08,181 --> 00:14:12,750 Scorpion vision is mostly tuned to daytime colors -- green, 314 00:14:12,752 --> 00:14:14,719 Which is fine when the sun is up, 315 00:14:14,721 --> 00:14:17,322 But at night, they need another way to detect 316 00:14:17,324 --> 00:14:19,224 Whether they're hidden properly. 317 00:14:19,226 --> 00:14:21,426 ♪ 318 00:14:23,363 --> 00:14:25,330 This is where we run our experiments 319 00:14:25,332 --> 00:14:27,899 To learn more about scorpions' reaction to light. 320 00:14:27,901 --> 00:14:31,436 Narrator: A team of scorpion scientists at the university of oklahoma 321 00:14:31,438 --> 00:14:33,738 Decided to find out how they manage it. 322 00:14:33,740 --> 00:14:37,008 Taylor: We'll take it out, and we put them in these little arenas. 323 00:14:37,010 --> 00:14:38,676 Narrator: These arenas will be floodlit 324 00:14:38,678 --> 00:14:42,881 Under the lights of a scorpion disco. 325 00:14:42,883 --> 00:14:46,017 And within these cylinders, we have small lights -- 326 00:14:46,019 --> 00:14:48,453 Either green lights or u.V. Lights. 327 00:14:48,455 --> 00:14:50,321 We put this on top. 328 00:14:50,323 --> 00:14:54,726 Within the box, we have a small infrared camera 329 00:14:54,728 --> 00:14:58,229 That videotapes them from below. 330 00:14:58,231 --> 00:15:00,798 Gaffin: So in our early experiments, we found 331 00:15:00,800 --> 00:15:03,902 That scorpions appear to be sort of agitated 332 00:15:03,904 --> 00:15:06,871 Under both green and u.V. Light. 333 00:15:06,873 --> 00:15:09,574 They kind of run in little spurts. 334 00:15:09,576 --> 00:15:17,115 ♪ 335 00:15:17,117 --> 00:15:20,551 Narrator: Shining both these lights on a scorpion makes it run, 336 00:15:20,553 --> 00:15:21,886 Because it senses the light 337 00:15:21,888 --> 00:15:25,456 And that it's exposed and therefore vulnerable. 338 00:15:25,458 --> 00:15:30,061 We decided to look to see if the eyes were responsible 339 00:15:30,063 --> 00:15:31,529 Or if different parts of the body 340 00:15:31,531 --> 00:15:34,098 Were responsible for this behavior. 341 00:15:34,100 --> 00:15:37,101 So we made these little tiny goggles out of foil 342 00:15:37,103 --> 00:15:38,636 To cover their eyes. 343 00:15:38,638 --> 00:15:41,806 ♪ 344 00:15:41,808 --> 00:15:44,108 Narrator: The experiment found that with tiny goggles 345 00:15:44,110 --> 00:15:45,610 Blocking their eyes, 346 00:15:45,612 --> 00:15:48,246 The scorpions didn't feel the need to run for cover 347 00:15:48,248 --> 00:15:49,580 Under green light. 348 00:15:49,582 --> 00:15:50,949 They couldn't see it, 349 00:15:50,951 --> 00:15:54,052 So didn't sense that they were out in the open. 350 00:15:54,054 --> 00:15:56,621 But they still ran when ultraviolet light 351 00:15:56,623 --> 00:15:57,855 Was shone on them. 352 00:15:57,857 --> 00:15:59,223 Gaffin: When we cover the eyes, 353 00:15:59,225 --> 00:16:02,961 We still see some behavior under ultraviolet light. 354 00:16:02,963 --> 00:16:06,531 So we had fairly clear difference in behavior, 355 00:16:06,533 --> 00:16:10,668 Suggesting that perhaps there was some sort of detection 356 00:16:10,670 --> 00:16:13,905 Of light beyond the eyes themselves. 357 00:16:13,907 --> 00:16:16,507 Narrator: So it seems that even when blindfolded, 358 00:16:16,509 --> 00:16:19,043 Somehow they were able to still see the u.V. 359 00:16:19,045 --> 00:16:21,713 With other parts of their body. 360 00:16:21,715 --> 00:16:25,183 We don't know exactly how they know they're glowing, 361 00:16:25,185 --> 00:16:26,918 But it's possible that signals from 362 00:16:26,920 --> 00:16:28,853 The u.V. Light-induced glow 363 00:16:28,855 --> 00:16:31,122 Could pass through nerves to their brain 364 00:16:31,124 --> 00:16:33,558 To tell them light is falling on them. 365 00:16:33,560 --> 00:16:36,961 The extraordinary conclusion from doug gaffin's work 366 00:16:36,963 --> 00:16:38,996 Is in effect, 367 00:16:38,998 --> 00:16:42,633 A scorpion is omnispective, all-seeing. 368 00:16:42,635 --> 00:16:44,469 ♪ 369 00:16:44,471 --> 00:16:46,871 Burke: Having this way of sensing u.V. Light 370 00:16:46,873 --> 00:16:48,473 Across the whole body 371 00:16:48,475 --> 00:16:50,608 Is a really clever way of making sure 372 00:16:50,610 --> 00:16:53,811 That when they're hiding, all of them is actually concealed 373 00:16:53,813 --> 00:16:57,715 And they haven't left any part of their body out and exposed. 374 00:16:57,717 --> 00:17:01,753 Narrator: Why is sensing u.V. In particular important? 375 00:17:01,755 --> 00:17:05,590 Because just after sunset when a scorpion is most active, 376 00:17:05,592 --> 00:17:09,527 The proportion of u.V. Light is at its highest. 377 00:17:09,529 --> 00:17:12,230 So if a scorpion were to scurry when startled 378 00:17:12,232 --> 00:17:13,865 And just any part of its body 379 00:17:13,867 --> 00:17:16,234 Were under a little twig or a leaf, 380 00:17:16,236 --> 00:17:19,837 It could reflexly move towards the shade 381 00:17:19,839 --> 00:17:22,940 And maybe have a measure of protection. 382 00:17:22,942 --> 00:17:25,209 Narrator: It looks like scorpions' attention-grabbing 383 00:17:25,211 --> 00:17:28,880 Fancy fluorescence is actually to help them hide, 384 00:17:28,882 --> 00:17:31,883 And maybe to help them see each other, too. 385 00:17:33,620 --> 00:17:38,189 [ insects chirping ] 386 00:17:38,191 --> 00:17:40,124 ♪ 387 00:17:40,126 --> 00:17:43,127 Narrator: April 2014. 388 00:17:43,129 --> 00:17:45,897 In northern iceland, a couple on a boat trip 389 00:17:45,899 --> 00:17:50,668 Film a dense cloud hanging over the surface of a lake. 390 00:17:50,670 --> 00:17:53,237 There's this apocalyptic cloud 391 00:17:53,239 --> 00:17:55,673 Rolling across this lake in iceland. 392 00:17:55,675 --> 00:17:58,443 This really thick, dense, dark cloud 393 00:17:58,445 --> 00:18:01,045 Hanging very, very low over the water. 394 00:18:01,047 --> 00:18:02,580 Narrator: What is causing it? 395 00:18:05,051 --> 00:18:07,819 [ volcanic rumbling ] 396 00:18:07,821 --> 00:18:11,089 Iceland is known as the "land of fire and ice." 397 00:18:11,091 --> 00:18:14,058 It's notorious for its ice, but when it comes to its fire, 398 00:18:14,060 --> 00:18:16,394 That's referring to its volcanic activity. 399 00:18:16,396 --> 00:18:18,062 [ volcanic rumbling ] 400 00:18:18,064 --> 00:18:21,065 A thought was, "well, could this be a cloud 401 00:18:21,067 --> 00:18:24,368 From a nearby volcano, an ash cloud or something?" 402 00:18:24,370 --> 00:18:27,338 Narrator: With over 30 active volcano systems, 403 00:18:27,340 --> 00:18:28,673 Iceland has history 404 00:18:28,675 --> 00:18:32,310 With belching out apocalyptic ash clouds. 405 00:18:32,312 --> 00:18:35,746 But no volcanic activity had been recorded at that time. 406 00:18:35,748 --> 00:18:37,615 ♪ 407 00:18:37,617 --> 00:18:40,952 It became obvious this was not smoke at all. 408 00:18:40,954 --> 00:18:44,388 Narrator: Because this ominous cloud is alive. 409 00:18:44,390 --> 00:18:46,824 ♪ 410 00:18:46,826 --> 00:18:49,227 [ insects chirping ] 411 00:18:55,702 --> 00:18:57,568 [ insects chirping ] 412 00:18:57,570 --> 00:18:59,770 ♪ 413 00:18:59,772 --> 00:19:02,673 Narrator: In iceland, an apocalyptic lake cloud 414 00:19:02,675 --> 00:19:05,776 Hangs in clear, blue sky. 415 00:19:05,778 --> 00:19:09,313 At first, it looked like volcanic ash or smoke 416 00:19:09,315 --> 00:19:11,849 Billowing across the surface. 417 00:19:11,851 --> 00:19:14,452 Only when you get a much closer look 418 00:19:14,454 --> 00:19:15,686 At actually what's going on, 419 00:19:15,688 --> 00:19:18,256 You start to see individual organisms. 420 00:19:18,258 --> 00:19:20,258 [ fluttering ] 421 00:19:20,260 --> 00:19:23,694 ♪ 422 00:19:23,696 --> 00:19:25,897 Of course, they are midges -- 423 00:19:25,899 --> 00:19:28,499 Thousands and thousands of midges. 424 00:19:28,501 --> 00:19:31,769 Narrator: Midges are tiny two-winged flies. 425 00:19:31,771 --> 00:19:35,640 And there aren't just thousands -- there are millions. 426 00:19:35,642 --> 00:19:38,509 When a million midges crash your boat trip, 427 00:19:38,511 --> 00:19:41,145 You have to get creative with headgear. 428 00:19:41,147 --> 00:19:44,148 [ fluttering ] 429 00:19:44,150 --> 00:19:46,984 Midges sure know how to wreck a boat trip. 430 00:19:46,986 --> 00:19:49,687 But why do they swarm like this? [ buzzing ] 431 00:19:49,689 --> 00:19:51,022 [ beeps ] 432 00:19:54,327 --> 00:19:55,927 ♪ 433 00:19:55,929 --> 00:19:58,162 Daly: Midges all hatch at the same time. 434 00:19:58,164 --> 00:20:00,498 That's what creates these huge clouds, 435 00:20:00,500 --> 00:20:02,600 And when they do form these huge clouds, 436 00:20:02,602 --> 00:20:05,136 It's really all about mating. 437 00:20:05,138 --> 00:20:06,771 Narrator: Midges hang out by lakes 438 00:20:06,773 --> 00:20:08,806 Because they need the water. 439 00:20:08,808 --> 00:20:10,174 They lay their eggs in it, 440 00:20:10,176 --> 00:20:11,842 And spend the first part of their life 441 00:20:11,844 --> 00:20:14,478 Living as larvae under the surface. 442 00:20:14,480 --> 00:20:17,949 Burke: Many species have this kind of life cycle. 443 00:20:17,951 --> 00:20:21,586 They might spend years as their larval stage underwater 444 00:20:21,588 --> 00:20:25,389 And only a few days or sometimes even a few hours as adults, 445 00:20:25,391 --> 00:20:27,191 And it's that brief little window 446 00:20:27,193 --> 00:20:29,227 Where they have an opportunity to mate. 447 00:20:29,229 --> 00:20:32,863 Narrator: Adult flying midges have no mouth parts and don't eat, 448 00:20:32,865 --> 00:20:35,032 So they have just a few days to do the deed 449 00:20:35,034 --> 00:20:37,068 And lay their eggs before they die 450 00:20:37,070 --> 00:20:39,303 So the cycle can begin again. 451 00:20:39,305 --> 00:20:40,771 And in lake myvatn, 452 00:20:40,773 --> 00:20:42,773 Which means "midge lake" in icelandic, 453 00:20:42,775 --> 00:20:44,475 Huge clouds of mating midges 454 00:20:44,477 --> 00:20:48,045 Will appear every few weeks during the summer months. 455 00:20:48,047 --> 00:20:50,014 Make sure you have a bucket handy. 456 00:20:50,016 --> 00:20:51,716 [ camera shutter clicks ] 457 00:20:51,718 --> 00:20:55,920 [ insects chirping ]