1 00:00:10,100 --> 00:00:13,820 Rarely seen, they have a near-mythical reputation. 2 00:00:15,700 --> 00:00:20,900 They have boundless energy and are able to dive deep... 3 00:00:22,860 --> 00:00:25,100 ..and catch the fastest of prey. 4 00:00:28,340 --> 00:00:29,380 Otters. 5 00:00:32,180 --> 00:00:35,260 My name is Charlie Hamilton James, 6 00:00:35,260 --> 00:00:38,660 wildlife cameraman and otter fanatic. 7 00:00:40,980 --> 00:00:45,980 I've been observing and filming these shy but relentless animals 8 00:00:45,980 --> 00:00:47,780 for the last 25 years. 9 00:00:48,860 --> 00:00:52,500 For me, otters are the ultimate predator, 10 00:00:52,500 --> 00:00:56,340 perfectly bridging the gap between two worlds - 11 00:00:56,340 --> 00:00:58,780 one dry, one wet. 12 00:01:02,140 --> 00:01:03,540 Yet across the planet, 13 00:01:03,540 --> 00:01:06,300 their populations have hung in the balance. 14 00:01:07,420 --> 00:01:11,060 I've done what I can for their conservation. 15 00:01:11,060 --> 00:01:12,700 However, many remain in danger. 16 00:01:14,060 --> 00:01:15,500 But otters are fighters... 17 00:01:16,900 --> 00:01:21,460 ..supercharged with a huge amount of spirit and determination. 18 00:01:22,860 --> 00:01:25,660 And now, with the help of three orphaned cubs... 19 00:01:28,060 --> 00:01:30,460 ..some ground-breaking experiments... 20 00:01:31,460 --> 00:01:34,340 It's done it, that was it! 21 00:01:34,340 --> 00:01:36,940 ..and some incredible wild encounters... 22 00:01:39,260 --> 00:01:43,100 ..I'm going to reveal their survival secrets 23 00:01:43,100 --> 00:01:47,580 and just why I think otters are such a special group of animals. 24 00:02:00,140 --> 00:02:02,020 I spent my life searching for 25 00:02:02,020 --> 00:02:04,860 glimpses of these rare and elusive creatures. 26 00:02:05,860 --> 00:02:07,700 They're nervous 27 00:02:07,700 --> 00:02:09,060 and fearful of humans. 28 00:02:11,140 --> 00:02:15,180 But there's one place where they're bolder than most - 29 00:02:15,180 --> 00:02:16,580 Florida. 30 00:02:20,860 --> 00:02:25,140 Here, clear, spring-fed rivers provide the ideal opportunity 31 00:02:25,140 --> 00:02:28,180 to film otters moving and hunting underwater. 32 00:02:31,620 --> 00:02:33,020 Something few have ever done. 33 00:02:36,100 --> 00:02:39,140 If I succeed, it'll be the perfect way 34 00:02:39,140 --> 00:02:41,180 to begin a journey into their seldom-seen world. 35 00:03:08,740 --> 00:03:09,820 They know I'm here. 36 00:03:10,900 --> 00:03:13,060 They're far too inquisitive not to have noticed. 37 00:03:14,100 --> 00:03:15,780 But they don't seem to mind. 38 00:03:24,060 --> 00:03:27,300 There are more otters here than anywhere I've ever been. 39 00:03:30,860 --> 00:03:33,540 But, typically, they don't keep still for long. 40 00:03:42,340 --> 00:03:46,140 North American river otters can cover over 40km a day... 41 00:03:47,540 --> 00:03:51,540 ..and swim for 400m without coming up for air. 42 00:03:53,780 --> 00:03:56,940 If you're going to observe otters in the wild, you need patience... 43 00:03:58,020 --> 00:03:59,060 ..and a bit of luck. 44 00:04:03,180 --> 00:04:04,660 I spot a telltale sign. 45 00:04:05,940 --> 00:04:07,340 A trail of bubbles. 46 00:04:17,700 --> 00:04:19,060 Absorbed by foraging... 47 00:04:20,060 --> 00:04:22,340 ..this is my chance to get close. 48 00:04:26,380 --> 00:04:28,380 I want to see how it's hunting. 49 00:04:30,020 --> 00:04:32,460 Something I've never achieved before. 50 00:04:34,740 --> 00:04:39,380 But I know just a flick of its tail and it could be off in a flash. 51 00:04:41,580 --> 00:04:42,820 He's so focused. 52 00:04:44,460 --> 00:04:45,860 I just need to hold my nerve. 53 00:04:58,460 --> 00:05:01,540 In 25 years of watching otters, I've just got these little glimpses 54 00:05:01,540 --> 00:05:04,140 occasionally of them underwater, 55 00:05:04,140 --> 00:05:07,020 and here, in a single morning, 56 00:05:07,020 --> 00:05:10,940 I've seen more otters underwater than in that whole 25 years. 57 00:05:15,140 --> 00:05:17,860 But what's been really interesting is actually looking 58 00:05:17,860 --> 00:05:19,060 at how they're hunting. 59 00:05:22,900 --> 00:05:26,660 It made me watch him and understand and look at the way he was doing 60 00:05:26,660 --> 00:05:28,420 stuff, the way he was swimming and fishing, 61 00:05:28,420 --> 00:05:29,780 in a completely different way. 62 00:05:34,220 --> 00:05:36,300 In this one incredible experience, 63 00:05:36,300 --> 00:05:40,540 a completely wild otter allowed me to come here, 64 00:05:40,540 --> 00:05:42,540 hang out and watch him fish underwater. 65 00:05:54,540 --> 00:05:56,540 There's an otter right there. 66 00:05:56,540 --> 00:05:57,540 HE CHORTLES 67 00:05:59,020 --> 00:06:01,860 This place is so amazing. 68 00:06:01,860 --> 00:06:04,420 There's just otters everywhere. It is otter heaven. 69 00:06:05,580 --> 00:06:07,540 I need to go get back in the water. 70 00:06:07,540 --> 00:06:10,420 It's all very well sitting here talking to the camera 71 00:06:10,420 --> 00:06:12,620 but I'd rather be swimming with an otter. 72 00:06:15,460 --> 00:06:17,500 The experience has reminded me why 73 00:06:17,500 --> 00:06:19,500 otters have captivated me for so long. 74 00:06:21,540 --> 00:06:23,580 They are incredible predators. 75 00:06:24,860 --> 00:06:26,620 Energetic, 76 00:06:26,620 --> 00:06:28,460 inquisitive 77 00:06:28,460 --> 00:06:29,460 and versatile - 78 00:06:31,940 --> 00:06:34,140 ..traits they share with their extended family. 79 00:06:35,540 --> 00:06:37,220 The mustelids. 80 00:06:37,220 --> 00:06:41,500 An ancient and diverse group of carnivores 81 00:06:41,500 --> 00:06:43,060 that includes weasels, 82 00:06:43,060 --> 00:06:46,780 stoats, badgers and martens. 83 00:06:46,780 --> 00:06:49,620 Otters can be found on nearly every continent, 84 00:06:49,620 --> 00:06:52,260 from the Arctic Circle 85 00:06:52,260 --> 00:06:54,580 to the swamps of Africa. 86 00:06:54,580 --> 00:06:59,820 And from desert oases to the tempestuous seas of Patagonia. 87 00:07:04,220 --> 00:07:06,900 But there are some things that unite all otter species. 88 00:07:09,060 --> 00:07:12,340 They have long, highly flexible bodies... 89 00:07:15,580 --> 00:07:17,620 ..a powerful tail 90 00:07:17,620 --> 00:07:18,660 and webbed feet. 91 00:07:22,100 --> 00:07:26,380 Some can dive to 100 metres... 92 00:07:26,380 --> 00:07:30,820 and hold their breath for over four minutes. 93 00:07:37,340 --> 00:07:41,620 But despite their amazing physical abilities, 94 00:07:41,620 --> 00:07:46,060 all over the world, otter numbers have been in decline. 95 00:07:46,060 --> 00:07:47,660 BARKING 96 00:07:49,500 --> 00:07:53,300 They've been hunted for sport 97 00:07:53,300 --> 00:07:54,740 and for their fur. 98 00:08:01,940 --> 00:08:04,100 They've lost their food to human greed... 99 00:08:06,860 --> 00:08:09,700 ..and have seen their habitat poisoned and ruined. 100 00:08:14,620 --> 00:08:19,140 But given the chance, otters are survivors 101 00:08:19,140 --> 00:08:21,700 enduring against all odds. 102 00:08:23,660 --> 00:08:27,780 It's one of the reasons I've always done what I can, 103 00:08:27,780 --> 00:08:29,340 caring for otters in need. 104 00:08:31,380 --> 00:08:34,180 I've even welcomed them into my family. 105 00:08:36,980 --> 00:08:39,860 Otter! 106 00:08:41,740 --> 00:08:42,860 Honey, a Eurasian otter 107 00:08:42,860 --> 00:08:44,740 too dependent on humans to be released... 108 00:08:46,420 --> 00:08:48,220 ..held a special place in my heart. 109 00:08:51,340 --> 00:08:57,140 And the time I spent with her only made by love for otters stronger. 110 00:09:02,660 --> 00:09:05,980 To help me reveal what I believe sets otters apart, 111 00:09:05,980 --> 00:09:09,300 I'm going to follow three male orphan river otters 112 00:09:09,300 --> 00:09:12,100 on their own story of survival. 113 00:09:13,420 --> 00:09:16,260 As they grow they'll be taught 114 00:09:16,260 --> 00:09:19,100 the vital skills they'll need for a life back in the wild. 115 00:09:22,420 --> 00:09:26,940 After being abandoned by their mothers, the orphans were brought 116 00:09:26,940 --> 00:09:29,740 to Wild Instincts wildlife rehab centre. 117 00:09:29,740 --> 00:09:33,260 On arrival they were weak, defenceless 118 00:09:33,260 --> 00:09:37,020 and would not have survived the night. 119 00:09:37,020 --> 00:09:39,940 Attempting to mirror their wild diet, 120 00:09:39,940 --> 00:09:44,980 centre manager Mark is giving them chopped fish and milk formula. 121 00:09:48,820 --> 00:09:52,100 But he has concerns about the weakest orphan. 122 00:09:52,100 --> 00:09:54,660 He came to us with a kind of a bad leg. 123 00:09:54,660 --> 00:09:56,700 He injured the joint on his right rear leg, 124 00:09:56,700 --> 00:10:00,140 so we're not quite sure whether it's going to heal enough for him 125 00:10:00,140 --> 00:10:03,340 to be released or not and he also did a slight injury to the joint 126 00:10:03,340 --> 00:10:05,620 right in here on this leg also 127 00:10:05,620 --> 00:10:09,260 and even the good leg is not necessarily a good leg. 128 00:10:09,260 --> 00:10:11,940 So what we're going to do is try to find a zoo for him 129 00:10:11,940 --> 00:10:14,580 if he's not able to be released back into the wild, 130 00:10:14,580 --> 00:10:16,380 and if we're unable to find a zoo then he 131 00:10:16,380 --> 00:10:20,020 may have to be euthanized if we can't find a place for him to go. 132 00:10:22,460 --> 00:10:24,940 To keep any attachment to a minimum, 133 00:10:24,940 --> 00:10:28,740 it's Mark's policy not to name any of the animals in his care. 134 00:10:32,420 --> 00:10:35,100 Now eight weeks old, 135 00:10:35,100 --> 00:10:37,900 the cubs need to tackle an essential survival skill - 136 00:10:39,420 --> 00:10:40,740 ..learning to swim. 137 00:10:46,380 --> 00:10:49,500 Curiously, baby otters don't really like water. 138 00:10:59,260 --> 00:11:04,140 So Mark needs to teach them their most important life lesson - 139 00:11:04,140 --> 00:11:07,020 that water isn't something to be afraid of. 140 00:11:12,260 --> 00:11:14,780 Just like their mother would in the wild, 141 00:11:14,780 --> 00:11:17,660 Mark makes soothing calls to reassure them. 142 00:11:17,660 --> 00:11:18,580 HE WARBLES SOFTLY 143 00:11:18,580 --> 00:11:19,980 OTTERS CHIRP IN RESPONSE 144 00:11:21,700 --> 00:11:24,100 Each time they try to get out, 145 00:11:24,100 --> 00:11:25,620 Mark plops them back in. 146 00:11:28,700 --> 00:11:31,300 But their swimming lessons don't last too long. 147 00:11:35,420 --> 00:11:38,620 That's because of another surprising quirk of otter biology. 148 00:11:40,500 --> 00:11:43,620 Their coat doesn't become waterproof until they are 12 weeks old. 149 00:11:45,180 --> 00:11:48,980 Until then, being wet could lead to hypothermia. 150 00:11:50,980 --> 00:11:54,740 So surrogate mum Mark does what he can to help out. 151 00:11:55,900 --> 00:11:58,340 Normally in the wild what they would be doing is rolling around in 152 00:11:58,340 --> 00:11:59,980 the grass and the dirt 153 00:11:59,980 --> 00:12:02,460 to get some of the water off themselves, 154 00:12:02,460 --> 00:12:04,500 so we can use the towels to help us out a little bit. 155 00:12:14,940 --> 00:12:18,500 Wild otter cubs face exactly the same issue, 156 00:12:18,500 --> 00:12:20,980 so the adults only take them for short dips 157 00:12:20,980 --> 00:12:23,500 to stop them getting cold and waterlogged. 158 00:12:38,100 --> 00:12:40,580 It's exactly what I saw with a family 159 00:12:40,580 --> 00:12:42,980 of giant river otters in the Amazon. 160 00:12:51,380 --> 00:12:54,220 Wow, look at that. Tiny! 161 00:12:56,460 --> 00:13:01,820 That is really young. That can't be more than six weeks old. 162 00:13:01,820 --> 00:13:03,020 He's got another one. 163 00:13:09,660 --> 00:13:12,220 Giant river otters are highly social 164 00:13:12,220 --> 00:13:16,460 and with such young pups in the water, the whole family helps out. 165 00:13:22,220 --> 00:13:24,260 They're too small to start swimming properly. 166 00:13:25,300 --> 00:13:26,940 It's just a taster session 167 00:13:26,940 --> 00:13:29,980 under the watchful eyes of their parents and siblings. 168 00:13:32,260 --> 00:13:35,660 Eventually, they'll become accomplished enough in the water 169 00:13:35,660 --> 00:13:38,260 to catch fast, wild prey. 170 00:13:47,260 --> 00:13:51,060 Back in Wisconsin, otter foster parent Mark is about to start 171 00:13:51,060 --> 00:13:53,900 teaching the orphans how to fish. 172 00:13:55,100 --> 00:13:58,380 But first the orphan with the bad leg needs a little extra help. 173 00:14:02,140 --> 00:14:04,580 So Mark has designed a swimming aid 174 00:14:04,580 --> 00:14:07,300 and is giving him a course of aquatherapy. 175 00:14:07,300 --> 00:14:09,780 OTTER CHIRRUPS FRANTICALLY 176 00:14:12,020 --> 00:14:14,900 So it looks like the little apparatus we have put on there seems 177 00:14:14,900 --> 00:14:18,180 to be accomplishing what we wanted it to do. It keeps him afloat 178 00:14:18,180 --> 00:14:21,780 and he's using his rear legs much better than he was before without it 179 00:14:21,780 --> 00:14:25,420 so hopefully this will be some good therapy and get him on the path 180 00:14:25,420 --> 00:14:26,620 to being what he needs to be. 181 00:14:30,860 --> 00:14:32,340 He's obviously a little fighter. 182 00:14:34,460 --> 00:14:35,660 As I arrive, 183 00:14:35,660 --> 00:14:38,500 Mark's just about to give them live fish for the first time. 184 00:14:44,940 --> 00:14:45,980 MARK WARBLES 185 00:14:48,180 --> 00:14:49,180 Oh, my God. 186 00:14:55,900 --> 00:14:58,740 Mark adds some minnows to the paddling pool 187 00:14:58,740 --> 00:15:01,980 and hopes that hunting is more instinctive than swimming. 188 00:15:04,580 --> 00:15:06,220 How cute is that? 189 00:15:06,220 --> 00:15:07,340 Go on, then. 190 00:15:10,580 --> 00:15:13,300 Yesterday we were doing a bit of diving and swimming around 191 00:15:13,300 --> 00:15:15,660 and now there'll be something to swim and dive around for 192 00:15:15,660 --> 00:15:18,020 so we'll see if they have any luck chasing around. 193 00:15:20,700 --> 00:15:23,700 This one's completely at home. It's just chased a fish. 194 00:15:23,700 --> 00:15:25,780 Exactly, exactly. 195 00:15:25,780 --> 00:15:27,580 Straightaway. And that's just in a few days. 196 00:15:27,580 --> 00:15:30,780 It's gone from nothing to chasing fish underwater. Right. 197 00:15:30,780 --> 00:15:32,420 He's got a fish. 198 00:15:32,420 --> 00:15:33,940 He's got one. 199 00:15:33,940 --> 00:15:35,460 He let it go. 200 00:15:35,460 --> 00:15:37,500 He's got it, he's got it. 201 00:15:37,500 --> 00:15:38,940 That's his first fish. 202 00:15:38,940 --> 00:15:39,980 Isn't that amazing? 203 00:15:40,980 --> 00:15:44,460 Yesterday he wasn't even putting his head underwater 204 00:15:44,460 --> 00:15:46,220 and today he caught his first little fish. 205 00:15:46,220 --> 00:15:49,020 That is amazing, isn't it? He's just rolling around playing with it. 206 00:15:49,020 --> 00:15:50,860 That's a great moment for them. Wow. 207 00:15:52,980 --> 00:15:55,380 Fishing, for the orphans, appears to be innate. 208 00:15:56,420 --> 00:15:58,460 It's a good sign. 209 00:15:58,460 --> 00:16:00,540 But it's something they'll need to hone. 210 00:16:02,300 --> 00:16:04,140 Do you know what? 211 00:16:05,500 --> 00:16:10,260 To me, there is nothing in the world that compares to otters. 212 00:16:10,260 --> 00:16:14,140 I could sit here all day every day and do nothing else for the rest of 213 00:16:14,140 --> 00:16:16,860 my life, just hang with otters. 214 00:16:16,860 --> 00:16:18,340 That's when I'm at my happiest. 215 00:16:20,380 --> 00:16:21,860 'As the orphans get bigger, 216 00:16:21,860 --> 00:16:25,500 'their swimming abilities will develop, too, 217 00:16:25,500 --> 00:16:28,700 'until they're as agile in the water as the fish they hunt.' 218 00:16:36,420 --> 00:16:39,580 But otters aren't just masters of the water. 219 00:16:39,580 --> 00:16:42,820 They spend up to 80% of their lives on land. 220 00:16:44,700 --> 00:16:49,940 Their ability to lead this semiaquatic double life is what allows them 221 00:16:49,940 --> 00:16:51,860 to cope with diverse habitats and prey. 222 00:16:54,900 --> 00:16:58,940 The key to this lies in their physiology, 223 00:16:58,940 --> 00:17:00,940 and back in the UK, 224 00:17:00,940 --> 00:17:05,220 I've got a furry friend to help reveal the secrets of their success. 225 00:17:07,620 --> 00:17:11,700 This is Rudy. He's an Asian small-clawed otter... 226 00:17:13,020 --> 00:17:16,020 ..or short-clawed otter, because he's got tiny little claws. 227 00:17:17,300 --> 00:17:20,420 And the aim is to get a really decent look at Rudy 228 00:17:20,420 --> 00:17:23,900 and how his body works, how his physiology works, 229 00:17:23,900 --> 00:17:26,820 how he turns from an animal that can run around on the land 230 00:17:26,820 --> 00:17:30,340 to an animal that's as fast as a fish in water, 231 00:17:30,340 --> 00:17:34,300 and it gives me an excuse to just hang out with an otter. 232 00:17:35,580 --> 00:17:37,740 I think you need to go and see the dentist, Rudy. 233 00:17:40,860 --> 00:17:45,180 This camera is going to do some nice slow motion shots 234 00:17:45,180 --> 00:17:49,660 and I can track along with the otter and then we can, you know, 235 00:17:49,660 --> 00:17:52,220 we can get a good look at how it's running. 236 00:17:52,220 --> 00:17:55,820 And Rod here is going to film Rudy swimming in close-up 237 00:17:55,820 --> 00:17:57,460 and particularly in slow motion. 238 00:17:59,340 --> 00:18:02,780 The thing I've always wondered, watching them and filming them, 239 00:18:02,780 --> 00:18:05,740 is how do they go from land to water and be so brilliant at both? 240 00:18:05,740 --> 00:18:08,820 And I think the reason I like what we're doing now is because we're 241 00:18:08,820 --> 00:18:11,740 going to get a really detailed look at that and try to get 242 00:18:11,740 --> 00:18:14,580 some understanding of how they manage to do that 243 00:18:14,580 --> 00:18:18,340 because very few animals can just flip between two worlds like that. 244 00:18:19,420 --> 00:18:20,740 Otters do it brilliantly. 245 00:18:23,820 --> 00:18:26,140 When we slow the action right down... 246 00:18:28,980 --> 00:18:30,940 ..we can see exactly what's going on. 247 00:18:35,460 --> 00:18:37,500 Otter spines are highly flexible... 248 00:18:38,940 --> 00:18:41,180 ..allowing Rudy to rotate his hips... 249 00:18:43,420 --> 00:18:48,260 ..swing his leg forward and plant his feet securely on the floor... 250 00:18:51,340 --> 00:18:54,340 ..and use his powerful tail for balance. 251 00:18:58,460 --> 00:19:01,300 And unlike most land-based carnivores, 252 00:19:01,300 --> 00:19:04,340 his front feet are well-developed 253 00:19:04,340 --> 00:19:08,060 with long, dextrous fingers for foraging and handling prey. 254 00:19:14,500 --> 00:19:18,140 By bending their highly flexible spines, 255 00:19:18,140 --> 00:19:20,220 otters are able to decrease the distance 256 00:19:20,220 --> 00:19:26,740 between the shoulder and hip by over 20%, allowing them to bound, 257 00:19:26,740 --> 00:19:28,300 running up to 18mph. 258 00:19:30,540 --> 00:19:35,220 But the adaptations that allows them to live a semiaquatic life 259 00:19:35,220 --> 00:19:38,900 become clearer as Rudy enters the water. 260 00:19:38,900 --> 00:19:41,660 A substance 800 times denser than air. 261 00:19:43,740 --> 00:19:45,980 As he puts his head into the water, 262 00:19:45,980 --> 00:19:48,780 his vision becomes blurry, just like it does for us. 263 00:19:51,100 --> 00:19:55,500 But an almost magical adaptation allows him to correct this, 264 00:19:55,500 --> 00:19:57,540 like an in-built pair of swimming goggles. 265 00:19:59,980 --> 00:20:02,820 At first, the density of the water stops light rays 266 00:20:02,820 --> 00:20:05,620 being brought into sharp focus on his retina. 267 00:20:07,900 --> 00:20:11,580 But Rudy has highly specialised muscles in his iris 268 00:20:11,580 --> 00:20:15,180 that squeeze the lens so that its face bulges forward. 269 00:20:16,860 --> 00:20:20,060 This refocuses the light rays onto the back of his eye... 270 00:20:21,220 --> 00:20:23,700 ..giving him sharp underwater vision. 271 00:20:25,740 --> 00:20:27,700 Now that he can see clearly, 272 00:20:27,700 --> 00:20:30,620 he enters the water fully and his next trick is revealed. 273 00:20:33,100 --> 00:20:36,460 Pushing his broad head forward and rotating his hips, 274 00:20:36,460 --> 00:20:39,180 he is able to straighten his body like a torpedo. 275 00:20:40,420 --> 00:20:43,620 Tucking his legs in, he reduces the water's drag... 276 00:20:47,940 --> 00:20:51,340 ..only untucking them when he wants a burst of speed. 277 00:20:54,220 --> 00:20:59,100 Next he uses his flexible spine in combination with his tail and 278 00:20:59,100 --> 00:21:01,940 webbed rear feet to turn and twist in the water. 279 00:21:04,980 --> 00:21:08,620 The agility of otters blows me away. 280 00:21:16,380 --> 00:21:19,740 Rudy has mastered the skills for a semiaquatic life 281 00:21:19,740 --> 00:21:24,020 but our orphans in Wisconsin are just learning how to make 282 00:21:24,020 --> 00:21:26,700 the most of their two worlds. 283 00:21:26,700 --> 00:21:29,580 They're now 12 weeks of age, 284 00:21:29,580 --> 00:21:32,980 old enough to move outside into an enclosure with permanent water... 285 00:21:37,220 --> 00:21:38,940 ..where Mark is going to introduce them 286 00:21:38,940 --> 00:21:40,100 to some different prey. 287 00:21:41,980 --> 00:21:45,700 So today we're going to do some freshwater clams, some crayfish, 288 00:21:45,700 --> 00:21:47,420 then we're also going to do some frogs. 289 00:21:47,420 --> 00:21:50,300 So we're going to start off by introducing the clams first and, 290 00:21:50,300 --> 00:21:52,500 since they really don't know what these things are, 291 00:21:52,500 --> 00:21:54,340 I'm going to cut them open for them, 292 00:21:54,340 --> 00:21:56,100 so I'm going to give each one a clam 293 00:21:56,100 --> 00:21:58,380 and then what we'll do is throw some in the pond, 294 00:21:58,380 --> 00:21:59,620 let them kind of figure it out, 295 00:21:59,620 --> 00:22:01,460 because they'll get the taste for it 296 00:22:01,460 --> 00:22:03,460 and realise that, hey, this is something I can eat. 297 00:22:05,300 --> 00:22:06,980 A wild otter's diet is broad. 298 00:22:08,260 --> 00:22:10,980 They catch and eat everything from snails to octopus. 299 00:22:13,220 --> 00:22:16,060 And their inquisitive nature has led 300 00:22:16,060 --> 00:22:19,300 to one species evolving an incredible talent - 301 00:22:19,300 --> 00:22:21,340 the use of tools. 302 00:22:26,540 --> 00:22:29,700 Sea otters feed on crustaceans and molluscs 303 00:22:29,700 --> 00:22:33,540 but their hard exoskeleton is notoriously tricky to get into. 304 00:22:40,460 --> 00:22:44,500 So each otter has preferred tools for accessing its favourite foods. 305 00:22:48,100 --> 00:22:50,780 Be it a rock for opening clams... 306 00:22:53,460 --> 00:22:55,940 ..the bow of an expensive boat for oysters... 307 00:23:03,220 --> 00:23:05,420 ..or an empty beer bottle for barnacles. 308 00:23:11,420 --> 00:23:14,100 By focusing on particular prey, 309 00:23:14,100 --> 00:23:16,780 sea otters have a balancing effect on the ecosystem... 310 00:23:17,820 --> 00:23:20,260 ..helping to keep it healthy. 311 00:23:24,140 --> 00:23:27,180 Otters seem to have a relentless curiosity. 312 00:23:27,180 --> 00:23:30,700 To me it's an indicator of just how intelligent they are. 313 00:23:33,260 --> 00:23:37,060 An endearing trait, and one that often results in play. 314 00:23:42,340 --> 00:23:45,260 Essential for all otters as they grow and develop... 315 00:23:49,340 --> 00:23:51,540 ..teaching them crucial life lessons. 316 00:24:15,740 --> 00:24:17,740 And it's exactly what I had to do with Honey... 317 00:24:18,740 --> 00:24:20,060 ..the otter I reared at home. 318 00:24:22,500 --> 00:24:24,260 HE GIGGLES 319 00:24:26,500 --> 00:24:29,580 But play for her wasn't always much fun for me. 320 00:24:29,580 --> 00:24:34,460 Ow! That's my skull! Ah, get off! 321 00:24:34,460 --> 00:24:37,460 This whole biting my skull thing, Honey, I'm not a fan. 322 00:24:42,900 --> 00:24:46,820 In social species, the bonds that play solidifies 323 00:24:46,820 --> 00:24:49,100 makes otter families a formidable force. 324 00:24:52,740 --> 00:24:55,500 Especially important for giant river otters, 325 00:24:55,500 --> 00:24:57,740 who regularly face deadly predators. 326 00:25:00,820 --> 00:25:02,860 With vulnerable young cubs, 327 00:25:02,860 --> 00:25:05,780 this family discovered a large black caiman in their territory. 328 00:25:12,140 --> 00:25:15,700 Identifying it as a threat, they work together, 329 00:25:15,700 --> 00:25:18,020 systematically attacking it. 330 00:25:31,860 --> 00:25:35,740 For three hours, the otters pinned it down, 331 00:25:35,740 --> 00:25:38,500 taking it in turns to attack its underside and head. 332 00:25:57,180 --> 00:26:01,660 Eventually, the enormous size and power of the caiman was no match 333 00:26:01,660 --> 00:26:07,220 for the family, whose bonds are so strong that they would risk dying for each other. 334 00:26:28,860 --> 00:26:31,220 For the orphans in Wisconsin, 335 00:26:31,220 --> 00:26:32,940 their best chance of a future in the wild 336 00:26:32,940 --> 00:26:34,460 will come from staying together. 337 00:26:36,500 --> 00:26:38,900 Now they can get a lot more exercise, 338 00:26:38,900 --> 00:26:42,500 start doing what they need to do and start being a lot less dependent on 339 00:26:42,500 --> 00:26:46,100 us, and we can start cutting off our human contact with them so they can 340 00:26:46,100 --> 00:26:49,500 learn to be otters and not rely on humans too much any more. 341 00:26:52,140 --> 00:26:55,180 They now have their most important piece of survival equipment - 342 00:26:57,820 --> 00:27:00,260 ..a warm and completely waterproof coat. 343 00:27:04,340 --> 00:27:06,540 Fur is an otter's secret weapon. 344 00:27:09,180 --> 00:27:10,980 They all rely on it to keep warm. 345 00:27:14,780 --> 00:27:17,380 But to understand its special qualities, 346 00:27:17,380 --> 00:27:19,140 we need to look at sea otters once again. 347 00:27:21,380 --> 00:27:25,420 They have the densest and most luxurious fur of any animal. 348 00:27:26,820 --> 00:27:28,300 It's such high quality 349 00:27:28,300 --> 00:27:32,180 that trappers historically measured all other fur against it. 350 00:27:33,620 --> 00:27:35,220 It's the main reason sea otters 351 00:27:35,220 --> 00:27:37,540 have been persecuted throughout their range. 352 00:27:40,700 --> 00:27:44,300 Their fur has nearly one million hairs per square inch. 353 00:27:48,580 --> 00:27:52,260 To properly appreciate the world's furriest animal, 354 00:27:52,260 --> 00:27:56,140 I've come to Monterey Bay Aquarium in California 355 00:27:56,140 --> 00:27:58,580 whose sea otter reintroduction programme has been 356 00:27:58,580 --> 00:28:00,780 instrumental in the recovery of the population. 357 00:28:03,860 --> 00:28:08,900 Beautiful. 'The aquarium's head vet, Dr Mike Murray, has anaesthetised 358 00:28:08,900 --> 00:28:10,540 'a female otter for a checkup, 359 00:28:10,540 --> 00:28:12,620 'giving me a chance to take a close look.' 360 00:28:13,820 --> 00:28:17,900 Look at the size of that. That's enormous! 361 00:28:17,900 --> 00:28:19,420 She actually feels really warm. 362 00:28:20,740 --> 00:28:24,780 That really, really thick fur they have is designed to conserve heat 363 00:28:24,780 --> 00:28:28,580 and she really doesn't, without cold water, have an opportunity to dump heat. 364 00:28:29,980 --> 00:28:32,020 Her coat is so effective 365 00:28:32,020 --> 00:28:34,900 that Dr Mike has to put bags of ice on her flippers 366 00:28:34,900 --> 00:28:36,380 to stop her overheating. 367 00:28:39,980 --> 00:28:43,700 This is the most beautiful, silky, soft fur you can imagine. 368 00:28:45,020 --> 00:28:47,460 On the outside it's much thicker 369 00:28:47,460 --> 00:28:52,820 but when you get down deep inside it's just silk-smooth. 370 00:28:52,820 --> 00:28:57,660 You can just make out the sort of pale, white skin underneath. 371 00:28:59,140 --> 00:29:01,140 It's amazing how wet it is on the outside 372 00:29:01,140 --> 00:29:04,100 and then you peel it back and it's completely dry on the inside. 373 00:29:06,300 --> 00:29:08,460 That is beautiful. 374 00:29:08,460 --> 00:29:10,540 It's so soft you can barely feel it. It's weird. 375 00:29:11,860 --> 00:29:14,540 And if you look at the undercoat, 376 00:29:14,540 --> 00:29:17,340 they've got these long guard hairs, but down deep, 377 00:29:17,340 --> 00:29:19,020 you look at those microscopically 378 00:29:19,020 --> 00:29:23,180 and they've got all these little scales that stick off the shaft of the fur 379 00:29:23,180 --> 00:29:25,700 and what the otter does when it grooms is, 380 00:29:25,700 --> 00:29:29,660 it just conditions the fur to get those things to lock together 381 00:29:29,660 --> 00:29:32,700 so that it becomes impenetrable to water, essentially, 382 00:29:32,700 --> 00:29:34,860 and they can get air in those spaces, 383 00:29:34,860 --> 00:29:38,260 very similar to a down jacket or down vest that we might be wearing. 384 00:29:39,780 --> 00:29:42,980 Looking at the undercoat in microscopic detail 385 00:29:42,980 --> 00:29:45,380 shows these scales lining the shaft of each hair. 386 00:29:46,820 --> 00:29:50,060 Grooming increases the volume of air trapped in this layer... 387 00:29:53,540 --> 00:29:56,540 ..maximising its insulation potential. 388 00:30:00,860 --> 00:30:03,780 And in the freezing waters of Alaska, 389 00:30:03,780 --> 00:30:06,180 survival relies on good insulation. 390 00:30:08,980 --> 00:30:11,620 This mother is fluffing up her baby's coat. 391 00:30:13,220 --> 00:30:14,860 By blowing into its fur 392 00:30:14,860 --> 00:30:17,660 she's filling it with air to keep him warm. 393 00:30:20,900 --> 00:30:23,580 The more trapped air, the warmer it is. 394 00:30:29,420 --> 00:30:32,780 But for it to be effective, it needs to be kept in top condition... 395 00:30:35,180 --> 00:30:38,700 ..which means otters spend hours each day grooming... 396 00:30:44,100 --> 00:30:48,220 ..using their flexible spine to reach those hard-to-get spots. 397 00:30:55,420 --> 00:30:59,860 We can see just how effective their coat is with the help of some technology. 398 00:31:01,820 --> 00:31:04,820 This is a thermal camera, so what it does, 399 00:31:04,820 --> 00:31:07,660 instead of looking at a straight image of something 400 00:31:07,660 --> 00:31:09,500 as we would normally look at through a camera, 401 00:31:09,500 --> 00:31:11,940 this looks at the heat signature of everything, so it can 402 00:31:11,940 --> 00:31:14,580 tell the difference between hot and cold and it shines up here. 403 00:31:14,580 --> 00:31:18,820 You know, the yellow bits are warmer, the purple bits are colder. 404 00:31:18,820 --> 00:31:20,660 It's going to be really interesting 405 00:31:20,660 --> 00:31:22,460 looking at the sea otter with this camera, 406 00:31:22,460 --> 00:31:25,340 because it'll show me which parts of the sea otter are retaining heat 407 00:31:25,340 --> 00:31:27,940 and which parts are giving off heat. 408 00:31:29,380 --> 00:31:31,180 OK, so she's right underneath me now. 409 00:31:31,180 --> 00:31:33,340 This is going to be a really nice shot. 410 00:31:33,340 --> 00:31:34,460 There she is. 411 00:31:38,740 --> 00:31:40,380 So you can see, looking at that, 412 00:31:40,380 --> 00:31:42,980 the bits that are really shining up yellow 413 00:31:42,980 --> 00:31:45,020 are her eyes and her mouth and nose 414 00:31:45,020 --> 00:31:47,300 and just a few bits on the side of her head, 415 00:31:47,300 --> 00:31:50,780 so those are the main bits that are losing heat. That's amazing. 416 00:31:53,140 --> 00:31:57,740 What's interesting is that the water temperature here's around 417 00:31:57,740 --> 00:32:02,260 7 Celsius, and her body temperature is around 37 Celsius. 418 00:32:02,260 --> 00:32:05,260 So we're actually looking at a 30-degree difference between 419 00:32:05,260 --> 00:32:07,100 the water temperature and her body, 420 00:32:07,100 --> 00:32:08,980 but we're not seeing it on the picture. 421 00:32:08,980 --> 00:32:10,820 Her body is almost the same colour as the water. 422 00:32:13,980 --> 00:32:15,300 So what that means is, 423 00:32:15,300 --> 00:32:17,860 that thick fur that the otter's got 424 00:32:17,860 --> 00:32:20,060 is so good at insulating the otter 425 00:32:20,060 --> 00:32:22,140 that very little heat is coming off it, 426 00:32:22,140 --> 00:32:24,860 almost no difference between the water temperature 427 00:32:24,860 --> 00:32:28,220 and the temperature of the otter on the outside of the otter 428 00:32:28,220 --> 00:32:31,740 because all the heat, that 37 degrees, is being kept inside. 429 00:32:36,900 --> 00:32:40,700 This highly specialised coat is one of the reasons otters 430 00:32:40,700 --> 00:32:43,700 are more capable on land than other semiaquatic mammals... 431 00:32:47,580 --> 00:32:48,900 ..like sea lions. 432 00:32:48,900 --> 00:32:50,420 SEA LIONS HONK 433 00:32:53,980 --> 00:33:00,140 One of the differences between these Californian sea lions and otters is 434 00:33:00,140 --> 00:33:04,060 not just the fact that they've given up their legs for flippers... 435 00:33:05,260 --> 00:33:08,300 ..but they're fat, great, big fat, lummoxing things. 436 00:33:08,300 --> 00:33:10,140 They're useless on land. 437 00:33:10,140 --> 00:33:13,700 This is pretty much the extent of what they can do on land, 438 00:33:13,700 --> 00:33:15,900 which is climb ashore and go to sleep. 439 00:33:15,900 --> 00:33:18,940 And otters? Otters can be really successful predators on land 440 00:33:18,940 --> 00:33:21,740 and the reason is, they don't have any blubber. 441 00:33:21,740 --> 00:33:23,940 These guys use blubber to keep themselves warm in the sea. 442 00:33:24,980 --> 00:33:28,620 Otters use fur, and one inch of fur 443 00:33:28,620 --> 00:33:33,380 is the equivalent, in insulating terms, of four inches of blubber. 444 00:33:41,020 --> 00:33:43,700 The otter's fur coat not only provides them 445 00:33:43,700 --> 00:33:46,100 with superb insulation in the water, 446 00:33:46,100 --> 00:33:49,740 it also allows them to have incredible agility on land... 447 00:33:53,220 --> 00:33:56,660 ..something the orphans in Wisconsin will need to take advantage of. 448 00:33:59,500 --> 00:34:01,700 At five months old, their confidence is growing. 449 00:34:02,780 --> 00:34:06,780 And their curious, intelligent nature is starting to shine through. 450 00:34:08,020 --> 00:34:09,900 So now what we can do is... 451 00:34:09,900 --> 00:34:12,060 So they know you're going to feed them, don't they? 452 00:34:12,060 --> 00:34:13,260 We can toss in a fish or two. 453 00:34:15,940 --> 00:34:18,340 And normally, as soon as you get a couple in there... 454 00:34:19,860 --> 00:34:22,020 Look at that, he's straight on it. Wow. 455 00:34:23,660 --> 00:34:25,300 That was so fast. 456 00:34:29,620 --> 00:34:32,780 It's so lovely to come back here and see how they've developed. 457 00:34:32,780 --> 00:34:35,740 I mean, they're just huge now, compared to what they were. 458 00:34:35,740 --> 00:34:39,340 They were tiny little, helpless, useless otters 459 00:34:39,340 --> 00:34:41,620 and, back then, we gave them their first fish 460 00:34:41,620 --> 00:34:45,060 and thought, "Wow, they can catch a fish, isn't that wonderful?" 461 00:34:45,060 --> 00:34:47,140 Now you watch them and they're just pros now. 462 00:34:48,100 --> 00:34:49,260 Exactly. 463 00:34:49,260 --> 00:34:50,460 If you look, 464 00:34:50,460 --> 00:34:52,380 now you have a hard time telling who 465 00:34:52,380 --> 00:34:53,940 the guy with the bum leg was. 466 00:34:53,940 --> 00:34:56,860 He doesn't show any sign of any problems any more. 467 00:34:56,860 --> 00:34:59,860 He's just as good as the other ones at catching fish 468 00:34:59,860 --> 00:35:02,060 and just as fast and agile as everybody else. 469 00:35:03,580 --> 00:35:07,580 I'm relieved that the injury to his back leg has recovered so well. 470 00:35:07,580 --> 00:35:11,620 It's testament to Mark's skills as a substitute mother. 471 00:35:11,620 --> 00:35:15,060 He's taken the camera out now. Look at that. 472 00:35:15,060 --> 00:35:17,460 The camera is going in. 473 00:35:17,460 --> 00:35:18,860 How can we get this in? 474 00:35:18,860 --> 00:35:20,740 They will figure it out. 475 00:35:20,740 --> 00:35:23,060 Oh, he's reframed it for us! 476 00:35:24,420 --> 00:35:26,460 They're just into everything, aren't they? 477 00:35:26,460 --> 00:35:28,980 Yeah. And that's otters for you, isn't it? 478 00:35:28,980 --> 00:35:33,460 Exactly. Crazy into everything. Everything. 479 00:35:33,460 --> 00:35:35,340 Just like this, with the block. 480 00:35:35,340 --> 00:35:38,700 You worry about them tipping the block over on themselves, and, er... 481 00:35:38,700 --> 00:35:40,460 Aww! 482 00:35:43,500 --> 00:35:45,140 There we go. It's sunk. 483 00:35:45,140 --> 00:35:46,740 THEY LAUGH 484 00:35:49,220 --> 00:35:53,420 They're now swimming around, looking at themselves underwater in it. 485 00:35:53,420 --> 00:35:54,900 They're doing otter selfies. 486 00:36:01,220 --> 00:36:05,020 'I just love their energy and determination.' 487 00:36:06,260 --> 00:36:09,300 These guys are clearly well on the way to having the skills 488 00:36:09,300 --> 00:36:13,780 they'll need to survive in the wild, and that time is fast approaching. 489 00:36:13,780 --> 00:36:17,900 Their release into Wisconsin's northern woods is only a month away. 490 00:36:19,220 --> 00:36:21,500 They've got each other. They do. 491 00:36:21,500 --> 00:36:25,500 I mean, one otter, you know, that's tricky. Three otters together? 492 00:36:25,500 --> 00:36:29,220 They can learn from each other, they are safer in numbers. Exactly. 493 00:36:29,220 --> 00:36:33,260 So they should do pretty well. They can certainly fish. 494 00:36:35,020 --> 00:36:36,740 So I think we'll go on out of here. 495 00:36:36,740 --> 00:36:39,380 they're starting to get a little bit too used to us. 496 00:36:39,380 --> 00:36:42,020 We're trying to keep our contact to a minimum 497 00:36:42,020 --> 00:36:44,300 so let's get on out of here. 498 00:36:44,300 --> 00:36:45,660 Cheers, guys. 499 00:36:48,060 --> 00:36:51,060 Mark's intentionally keeping contact with the orphans to a minimum. 500 00:36:52,980 --> 00:36:55,980 They need to be as independent as possible ahead of their release. 501 00:37:04,140 --> 00:37:06,460 Although they're doing well, 502 00:37:06,460 --> 00:37:10,940 catching fast, wild fish in a big open lake or flowing river 503 00:37:10,940 --> 00:37:13,780 will present them with an enormous challenge. 504 00:37:20,420 --> 00:37:23,500 They'll need to bring all their knowledge and skills together. 505 00:37:35,180 --> 00:37:40,420 To reveal how otters do this, I'm heading to Oakland Zoo in California 506 00:37:40,420 --> 00:37:44,980 where I hope to film a hunt in super-slow motion. 507 00:37:44,980 --> 00:37:49,860 Here, they enrich the lives of the otters by feeding them live prey - 508 00:37:49,860 --> 00:37:50,900 goldfish. 509 00:37:52,300 --> 00:37:57,180 Helping me dissect the action is biology professor Lei Lani Stelle. 510 00:37:57,180 --> 00:38:00,580 Check this out, Lei Lani. What this will allow us to do, 511 00:38:00,580 --> 00:38:05,100 while the otter's swimming, I can track along with it and it shoots in 512 00:38:05,100 --> 00:38:07,020 really decent slow motion. 513 00:38:07,020 --> 00:38:09,980 We can basically slow things down ten times. 514 00:38:09,980 --> 00:38:14,140 Wow, that'll give us amazing detail on what they're doing right at the 515 00:38:14,140 --> 00:38:17,380 moment when they see their food and are able to catch it. 516 00:38:19,740 --> 00:38:22,340 He's going for it. Wow! That was nice, wasn't it? 517 00:38:25,180 --> 00:38:27,420 Look at them chasing it together. 518 00:38:29,460 --> 00:38:31,700 He's having trouble getting that one! 519 00:38:31,700 --> 00:38:33,500 Look at that! 520 00:38:33,500 --> 00:38:35,580 Got it. 521 00:38:35,580 --> 00:38:41,420 Awesome. OK, let's have a look, see what we've got. 522 00:38:41,420 --> 00:38:43,100 Where's the play button? 523 00:38:48,660 --> 00:38:50,820 That's so cool to see it in slow motion, 524 00:38:50,820 --> 00:38:53,660 so you can see all of the details of the moving. 525 00:38:53,660 --> 00:38:56,740 When we were watching it, it was so fast it was hard to see. 526 00:39:00,540 --> 00:39:03,180 It's incredibly agile, isn't it? 527 00:39:06,260 --> 00:39:08,980 Yeah, you can see him doing a really quick turn 528 00:39:08,980 --> 00:39:13,780 and you can definitely see how flexible his spine is. 529 00:39:13,780 --> 00:39:17,140 So it really is, I guess, the spine doing a load of work 530 00:39:17,140 --> 00:39:20,460 and then when he needs to get the fish, the back legs seem to come out. 531 00:39:23,300 --> 00:39:26,060 And that's how, I guess, how they get that turn of speed. 532 00:39:29,220 --> 00:39:34,420 The flexible spine combined with its tail and webbed hind feet 533 00:39:34,420 --> 00:39:39,300 allow the otter supreme agility and speed in the water. 534 00:39:41,380 --> 00:39:44,660 In the final approach, it uses its underwater eyesight 535 00:39:44,660 --> 00:39:46,900 to place the fish right in front of its head. 536 00:39:59,180 --> 00:40:01,700 That's right on the tail of the fish, isn't it? 537 00:40:01,700 --> 00:40:03,900 He kind of nudged it with his nose first. Yeah. 538 00:40:04,940 --> 00:40:08,700 It definitely seems like we're noticing that they're feeling the 539 00:40:08,700 --> 00:40:10,220 fish more than anything, 540 00:40:10,220 --> 00:40:13,180 so it may be that they're detecting it with 541 00:40:13,180 --> 00:40:16,940 their whiskers first and since that has a hard-wire 542 00:40:16,940 --> 00:40:19,940 from the whiskers right to the jaw, 543 00:40:19,940 --> 00:40:21,500 they can just bite it with instinct 544 00:40:21,500 --> 00:40:24,460 without having to take that time for the brain to process the signal. 545 00:40:25,820 --> 00:40:27,900 So they're not, you know, they're not feeling it 546 00:40:27,900 --> 00:40:30,180 and thinking, "Is that to my left? Is that to my right?" 547 00:40:30,180 --> 00:40:33,580 Right. It's like an instant...like us seeing or hearing. 548 00:40:33,580 --> 00:40:37,660 Yeah. Exactly, there's no delay. And that would explain how they're 549 00:40:37,660 --> 00:40:39,500 able to pick up on the fish so quickly. 550 00:40:39,500 --> 00:40:42,940 Because I would have trouble seeing the fish and they would already grab it. 551 00:40:42,940 --> 00:40:44,940 Right. And it is incredibly fast, isn't it? 552 00:40:49,820 --> 00:40:52,220 As soon as the prey touches the whiskers, 553 00:40:52,220 --> 00:40:55,940 an incredible nervous reaction is triggered. 554 00:40:55,940 --> 00:41:00,740 The signal fired to the brain is immediately turned into a command, 555 00:41:00,740 --> 00:41:04,060 stimulating the jaw to grab. 556 00:41:04,060 --> 00:41:09,060 Cutting out any decision-making delay. 557 00:41:10,340 --> 00:41:13,180 And it all happens in a fraction of a second. 558 00:41:19,460 --> 00:41:23,380 'But I've spotted something else intriguing in the footage.' 559 00:41:25,380 --> 00:41:28,220 That otter's nosing that fish and sniffing the fish, right? 560 00:41:29,660 --> 00:41:33,500 And if you look, when it first comes up to it, it puts bubbles out. 561 00:41:33,500 --> 00:41:36,140 It's got loads of bubbles around its mouth. Right. 562 00:41:36,140 --> 00:41:39,420 Because I'm convinced otters can smell underwater. 563 00:41:39,420 --> 00:41:42,660 So do you think the bubbles are going back into the nose or into the mouth? 564 00:41:42,660 --> 00:41:44,980 I think they're going into both. Interesting. 565 00:41:44,980 --> 00:41:47,700 It's not improbable because a lot of animals can smell 566 00:41:47,700 --> 00:41:50,580 underwater, right? And it's just a chemical cue 567 00:41:50,580 --> 00:41:54,020 and as long as it's concentrated, so it's really right close to them, 568 00:41:54,020 --> 00:41:57,260 it makes sense that they would still be able to smell it underwater. 569 00:41:59,900 --> 00:42:01,940 So other animals that can smell underwater, 570 00:42:01,940 --> 00:42:07,020 do they just sniff in water or do they use bubbles in this way? 571 00:42:07,020 --> 00:42:09,580 You know, to be honest, I don't think anyone knows. 572 00:42:12,300 --> 00:42:16,540 It's thrilling to think that otters' ability to smell underwater 573 00:42:16,540 --> 00:42:19,220 could in fact be an undiscovered survival skill. 574 00:42:21,580 --> 00:42:25,740 I've long thought otters must have this secret ability, and seeing 575 00:42:25,740 --> 00:42:28,420 this has inspired me to put my theory to the test. 576 00:42:37,500 --> 00:42:40,500 I'm hoping Rudy might be able to help me once again. 577 00:42:42,940 --> 00:42:47,820 So really the only definitive way of proving that otters can smell 578 00:42:47,820 --> 00:42:49,820 underwater is to do an experiment, 579 00:42:49,820 --> 00:42:52,980 so we're going to get some fake fish and some real fish 580 00:42:52,980 --> 00:42:56,700 and we're going to try and film Rudy telling the difference 581 00:42:56,700 --> 00:42:59,020 between the fake fish and real fish. 582 00:42:59,020 --> 00:43:02,660 So what we've got here is a fake piece of plastic trout. 583 00:43:05,220 --> 00:43:08,740 We're going to put that on here 584 00:43:08,740 --> 00:43:11,620 and we present Rudy with 585 00:43:11,620 --> 00:43:14,540 two identical-looking pieces of fish... 586 00:43:16,500 --> 00:43:19,060 ..to see if he can tell the difference. 587 00:43:19,060 --> 00:43:22,420 So we're going to put this experimental block here... 588 00:43:23,780 --> 00:43:24,860 ..underwater. 589 00:43:28,260 --> 00:43:31,660 'This relies on Rudy investigating each piece underwater. 590 00:43:33,500 --> 00:43:36,180 'Deciding which one is food and then eating it. 591 00:43:37,420 --> 00:43:42,140 'And Rod and I capturing the whole thing on camera in slow motion.' 592 00:43:46,620 --> 00:43:48,540 No interest in the fake one. 593 00:43:51,220 --> 00:43:52,460 Absolutely none. 594 00:43:58,580 --> 00:44:00,740 Well, come on, Rudy, do it. 595 00:44:03,380 --> 00:44:05,060 It's so fast and it's so subtle, 596 00:44:05,060 --> 00:44:08,540 that it's very difficult to work out exactly what's going on. 597 00:44:09,900 --> 00:44:14,580 'My camera simply isn't capable of slowing it down enough to see the finer details. 598 00:44:15,660 --> 00:44:20,260 'But Rod's camera captures the action 40 times slower than real life.' 599 00:44:22,500 --> 00:44:24,700 Right, Rod, did you get it? 600 00:44:24,700 --> 00:44:26,100 Possibly. Really? 601 00:44:26,100 --> 00:44:31,060 Yeah. It's so quick and obviously we're slowing it down 40 times, 602 00:44:31,060 --> 00:44:33,660 so until we actually see it... 603 00:44:33,660 --> 00:44:36,500 So that... God, that is a close shot. There's his head. 604 00:44:41,020 --> 00:44:43,220 That's a bubble coming out of his mouth, isn't it? 605 00:44:45,820 --> 00:44:47,300 Oh, he's sucked it back in. 606 00:44:47,300 --> 00:44:48,900 It's done it. No way. 607 00:44:48,900 --> 00:44:51,340 That was it. Fantastic. 608 00:44:51,340 --> 00:44:52,340 That's amazing. 609 00:44:53,340 --> 00:44:55,140 A bubble came out of his mouth 610 00:44:55,140 --> 00:44:59,140 and just as he was lifting his head, he sucked it right back in again. 611 00:44:59,140 --> 00:45:01,340 It wasn't his nose, but it was his mouth. 612 00:45:01,340 --> 00:45:04,180 He draws it back in, tasting the fish. 613 00:45:05,580 --> 00:45:11,900 That's amazing, because you can actually see it happening perfectly. 614 00:45:11,900 --> 00:45:15,900 'Rudy actively pushes a bubble onto the surface of the fish... 615 00:45:17,580 --> 00:45:20,780 '..picking up scent molecules before he sucks it back in... 616 00:45:22,660 --> 00:45:27,140 '..obtaining enough information to determine whether it's something he wants to eat. 617 00:45:29,300 --> 00:45:33,220 'This footage helps me understand how otters might find food in 618 00:45:33,220 --> 00:45:37,460 'dark, murky waters where they can't rely on their underwater eyesight. 619 00:45:39,460 --> 00:45:41,660 'They sniff it out. 620 00:45:41,660 --> 00:45:44,740 'It's amazing to think that an animal we are so familiar with... 621 00:45:46,460 --> 00:45:48,300 '..may still hold secrets from us.' 622 00:45:53,940 --> 00:45:57,740 And good to think that the orphans may have this ability too. 623 00:46:00,380 --> 00:46:04,300 The cubs are six months old now and autumn is coming. 624 00:46:04,300 --> 00:46:05,820 It's time for their release. 625 00:46:07,380 --> 00:46:10,740 With his parenting nearly over, Mark has built a pen... 626 00:46:12,300 --> 00:46:15,020 ..which he'll leave on the shores of an isolated lake. 627 00:46:16,860 --> 00:46:20,220 'This will give the orphans somewhere familiar to come back to 628 00:46:20,220 --> 00:46:22,540 'until they're able to fend for themselves.' 629 00:46:22,540 --> 00:46:23,540 All set? 630 00:46:23,540 --> 00:46:26,820 Wow, this is the moment, guys. 631 00:46:26,820 --> 00:46:28,340 MARK WARBLES 632 00:46:31,140 --> 00:46:34,460 Oh, look at that. 633 00:46:37,180 --> 00:46:39,020 How amazing. 634 00:46:39,020 --> 00:46:41,020 You can't imagine what it's like. It's like... 635 00:46:41,020 --> 00:46:42,300 MARK WARBLES 636 00:46:42,300 --> 00:46:44,740 ..having never been outside in your life, isn't it? 637 00:46:44,740 --> 00:46:47,500 Exactly. All these new, funny things to explore. 638 00:46:52,820 --> 00:46:55,140 They're so funny. They're just into everything. 639 00:46:55,140 --> 00:46:56,300 They run for about ten feet 640 00:46:56,300 --> 00:46:58,180 and then stop and look around and then they run. 641 00:47:00,140 --> 00:47:02,260 They're just crazy. 642 00:47:02,260 --> 00:47:04,780 They're checking everything out. 643 00:47:04,780 --> 00:47:06,220 Checking my tripod out. 644 00:47:14,620 --> 00:47:17,700 You know what's lovely is the point where they get to the water... 645 00:47:19,020 --> 00:47:22,860 ..because they're suddenly going to be otters, finally. 646 00:47:22,860 --> 00:47:25,500 It's all very well looking like an otter, 647 00:47:25,500 --> 00:47:27,260 but to actually be free and be 648 00:47:27,260 --> 00:47:30,380 swimming and catching fish, that's the special bit. 649 00:47:53,380 --> 00:47:56,900 So this is the accumulation of all of our efforts coming to the end 650 00:47:56,900 --> 00:48:00,260 and this is the kind of moment we've been waiting for since we started. 651 00:48:03,700 --> 00:48:07,420 And gives you a lot of satisfaction to be able to see them out there, 652 00:48:07,420 --> 00:48:09,580 swimming and doing what they're doing... 653 00:48:11,020 --> 00:48:13,260 ..knowing that you had a chance to set it right 654 00:48:13,260 --> 00:48:15,500 for what went wrong in the first place. 655 00:48:17,260 --> 00:48:19,740 We'll still continue to put food out for them 656 00:48:19,740 --> 00:48:22,540 but they need to find their independence now. 657 00:48:22,540 --> 00:48:24,660 And they're smart enough to do it. 658 00:48:24,660 --> 00:48:26,860 I mean, you're still kind of mum, aren't you? 659 00:48:26,860 --> 00:48:28,420 But you're a hands-off mum. 660 00:48:28,420 --> 00:48:29,940 Exactly. 661 00:48:29,940 --> 00:48:33,580 Today we cut the apron strings a little bit. Right. 662 00:48:33,580 --> 00:48:39,420 'And it's obvious that the orphans are relishing their first real taste of freedom.' 663 00:48:39,420 --> 00:48:42,100 They'll just keep expanding their range little by little and start 664 00:48:42,100 --> 00:48:44,540 checking things out and getting more adventurous 665 00:48:44,540 --> 00:48:47,780 and eventually they'll go probably around the whole lake 666 00:48:47,780 --> 00:48:50,220 and, not too much longer, they'll probably start heading 667 00:48:50,220 --> 00:48:52,060 up and down the creeks that are 668 00:48:52,060 --> 00:48:54,380 coming in and out and seeing what's there. 669 00:48:59,180 --> 00:49:02,220 'In the same way a mother otter would keep catching fish 670 00:49:02,220 --> 00:49:04,140 'for her young at this age in the wild... 671 00:49:05,340 --> 00:49:07,500 '..until Mark is sure that they're using 672 00:49:07,500 --> 00:49:09,420 'all their learned and innate skills 673 00:49:09,420 --> 00:49:12,180 'he'll keep putting out food for them.' 674 00:49:12,180 --> 00:49:15,420 And what happens, do you stop feeding them first and then they go 675 00:49:15,420 --> 00:49:17,260 or do they generally just move off? 676 00:49:17,260 --> 00:49:20,700 They generally just move off, so we'll offer food for a while until 677 00:49:20,700 --> 00:49:22,980 we notice the food's not disappearing any more 678 00:49:22,980 --> 00:49:24,540 and we don't see them any more. 679 00:49:26,380 --> 00:49:28,340 So it's their first night alone, now, isn't it? 680 00:49:28,340 --> 00:49:31,060 Yeah, it'll be the first night alone but I think they'll do just fine. 681 00:49:31,060 --> 00:49:32,860 They've had a lot of fun today and I think 682 00:49:32,860 --> 00:49:34,900 they're just going to find a place to go to sleep. 683 00:49:40,940 --> 00:49:42,460 I think they're going to sleep well. 684 00:49:42,460 --> 00:49:44,860 I think so, too. They got a good supper, they should be good. 685 00:49:47,100 --> 00:49:51,180 'As night falls, I can't help but worry for them. 686 00:49:51,180 --> 00:49:53,660 'Although Mark's provided them with food, 687 00:49:53,660 --> 00:49:55,660 'for the first time in their lives 688 00:49:55,660 --> 00:49:57,660 'they will have no-one looking out for them.' 689 00:50:11,860 --> 00:50:14,740 'As soon as it's light I'm keen to check up on the orphans. 690 00:50:21,460 --> 00:50:25,500 'At first there doesn't seem to be any sign of them. 691 00:50:33,220 --> 00:50:35,420 'But then I hear some familiar chirps.' 692 00:50:35,420 --> 00:50:36,500 CHIRPING 693 00:50:44,580 --> 00:50:47,820 'I'm delighted. All three are foraging together.' 694 00:50:58,220 --> 00:51:02,500 There's something about when you see a group of otters like this, you know, 695 00:51:02,500 --> 00:51:06,300 three otters almost like this one animal and three bodies. 696 00:51:06,300 --> 00:51:11,060 They move so perfectly, so in sync with each other. 697 00:51:11,060 --> 00:51:12,900 They know where each other is the whole time. 698 00:51:12,900 --> 00:51:14,460 They know what each other is doing. 699 00:51:14,460 --> 00:51:16,460 Even though sometimes they can't see each other. 700 00:51:16,460 --> 00:51:19,380 You know, this is really murky, peaty water. 701 00:51:19,380 --> 00:51:23,460 They can't see in it, but they always know where each other is. 702 00:51:30,700 --> 00:51:35,020 For Mark to have got them from three tiny cubs to this state 703 00:51:35,020 --> 00:51:38,020 and to put them in this place and release them so quickly 704 00:51:38,020 --> 00:51:42,180 and so effectively is brilliant. I think he's done a great job. 705 00:51:46,260 --> 00:51:49,660 Just looking at these guys from this canoe, 706 00:51:49,660 --> 00:51:52,060 it's just like watching a group of wild otters 707 00:51:52,060 --> 00:51:54,140 and they're doing everything that wild otters do. 708 00:51:54,140 --> 00:51:55,780 They're behaving like wild otters. 709 00:51:55,780 --> 00:51:58,100 They're hunting along in the reeds and the lilies 710 00:51:58,100 --> 00:52:01,500 along the edge of the lake. 711 00:52:01,500 --> 00:52:04,020 And they're foraging. That's what otters do. 712 00:52:04,020 --> 00:52:07,380 They're not always out in the middle of the lake speeding after fish. 713 00:52:07,380 --> 00:52:10,260 Most of the time they spend nosing around in the weeds 714 00:52:10,260 --> 00:52:13,940 trying to find some food, and that's exactly what these guys are doing. 715 00:52:13,940 --> 00:52:15,620 So it makes me very hopeful. 716 00:52:15,620 --> 00:52:20,060 You look at them behaving like real, wild otters and you think, well, 717 00:52:20,060 --> 00:52:23,060 if you can do that within 24 hours of being released, 718 00:52:23,060 --> 00:52:25,820 I think the chances of survival for these guys are pretty high. 719 00:52:32,260 --> 00:52:35,180 'Mark has given the orphans a real second chance at life. 720 00:52:37,420 --> 00:52:39,980 'And as long as they stick together, 721 00:52:39,980 --> 00:52:42,820 'harness everything their surrogate mum has taught them... 722 00:52:43,860 --> 00:52:46,380 '..alongside their own natural instincts, 723 00:52:46,380 --> 00:52:48,900 'they should be able to cope with most things.' 724 00:52:59,380 --> 00:53:03,340 I'm reassured that otters have what it takes to survive. 725 00:53:03,340 --> 00:53:05,140 History has shown this. 726 00:53:07,780 --> 00:53:10,220 Where otter populations were at record lows... 727 00:53:11,260 --> 00:53:12,660 ..some are now coming back. 728 00:53:14,500 --> 00:53:19,540 40 years ago, the Eurasian otter was extinct across most of the UK. 729 00:53:22,180 --> 00:53:23,820 Now it's found in every county. 730 00:53:27,940 --> 00:53:32,380 And the sea otter numbered just 2,000 individuals a century ago. 731 00:53:35,020 --> 00:53:40,100 But with the help of protection and reintroduction programmes 732 00:53:40,100 --> 00:53:43,540 has made a population increase to 125,000. 733 00:53:48,780 --> 00:53:51,460 We can't get complacent. 734 00:53:51,460 --> 00:53:54,740 Across the globe otters ARE threatened, 735 00:53:54,740 --> 00:53:58,580 but where they're given the chance, they can adapt to a changing world. 736 00:53:58,580 --> 00:54:00,420 CHIRPING 737 00:54:00,420 --> 00:54:04,700 And there's one place where they've made a very surprising comeback. 738 00:54:12,380 --> 00:54:14,180 Downtown Singapore. 739 00:54:24,740 --> 00:54:28,460 Singapore is one of the busiest countries in the world. 740 00:54:30,540 --> 00:54:34,540 Attracting over 15 million visitors a year, 741 00:54:34,540 --> 00:54:37,340 it might not seem like a haven for wildlife. 742 00:54:38,980 --> 00:54:41,260 But despite the hustle and bustle, 743 00:54:41,260 --> 00:54:45,500 and having been thought extinct here just a few decades ago, 744 00:54:45,500 --> 00:54:50,460 in 2014, smooth-coated otters moved into the city centre. 745 00:54:54,540 --> 00:54:57,860 There are now thought to be well over 60 otters 746 00:54:57,860 --> 00:55:00,100 living inside the city state. 747 00:55:02,380 --> 00:55:06,900 The reason? Fresh water in Singapore's Marina Bay has, 748 00:55:06,900 --> 00:55:09,660 for the last nine years, been highly protected. 749 00:55:11,660 --> 00:55:14,220 There's next to no fishing or pollution. 750 00:55:16,740 --> 00:55:20,620 The result is a vast reservoir, absolutely full of fish. 751 00:55:23,660 --> 00:55:25,420 Perfect for otters. 752 00:55:28,660 --> 00:55:31,140 And now, on a daily basis, 753 00:55:31,140 --> 00:55:34,260 they demonstrate one of the characteristics I love most. 754 00:55:36,700 --> 00:55:38,900 Their close family bond. 755 00:55:43,620 --> 00:55:45,940 What's really freaking me out is that 756 00:55:45,940 --> 00:55:49,900 the last time I filmed a group of otters this big and this social 757 00:55:49,900 --> 00:55:52,820 and exciting was in one of the remotest parts of the Amazon. 758 00:55:52,820 --> 00:55:56,620 That was a group of giant otters, 15 of them. 759 00:55:56,620 --> 00:56:00,900 Now I've got 13 completely wild otters right in the middle of, 760 00:56:00,900 --> 00:56:04,940 I guess, one of the most densely populated cities on earth. 761 00:56:07,820 --> 00:56:12,060 'And this family has just expanded Singapore's population even further. 762 00:56:14,620 --> 00:56:17,300 'They have four 11-week-old pups.' 763 00:56:23,620 --> 00:56:26,660 'And just like the orphans in Wisconsin, 764 00:56:26,660 --> 00:56:29,060 'they, too, are on a journey of survival.' 765 00:56:47,980 --> 00:56:49,620 Otters are very sensitive animals. 766 00:56:49,620 --> 00:56:53,060 They've been in trouble across the world for a long time now. 767 00:56:53,060 --> 00:56:56,900 But, if Singapore proves anything to me, it's that they are adaptable. 768 00:56:57,980 --> 00:57:00,540 'I've no doubt otters are survivors. 769 00:57:04,660 --> 00:57:07,900 'For me, it's all about their supercharged nature. 770 00:57:10,340 --> 00:57:14,300 'And I think it's this that makes me smile every time I see one. 771 00:57:15,820 --> 00:57:19,420 'And here in Singapore there are plenty of other smiling faces. 772 00:57:20,940 --> 00:57:25,820 'That's because otters ARE special and, given a chance, 773 00:57:25,820 --> 00:57:28,580 'will always make the most of what's available to them.' 774 00:57:29,780 --> 00:57:33,780 They need nice, clean water, a decent supply of food, 775 00:57:33,780 --> 00:57:37,020 and they need to be free from persecution. 776 00:57:38,020 --> 00:57:42,060 And clearly, Singapore's provided them the perfect home. 777 00:57:48,500 --> 00:57:52,900 And that basically proves to me that these shy, nocturnal, 778 00:57:52,900 --> 00:57:55,860 secretive animals that we kind of all think otters are, 779 00:57:55,860 --> 00:57:58,260 give them the right ingredients for life... 780 00:57:59,620 --> 00:58:01,900 ..protect them, and they'll thrive. 781 00:58:20,220 --> 00:58:23,860 And in the weeks and months following their release, 782 00:58:23,860 --> 00:58:27,700 through autumn and winter, the orphans in Wisconsin 783 00:58:27,700 --> 00:58:29,340 are also thriving.