1 00:00:06,440 --> 00:00:11,280 The world's oceans are full of wonder... 2 00:00:11,440 --> 00:00:14,400 an alien world waiting to be explored... 3 00:00:17,560 --> 00:00:21,680 ...a place of extraordinary life-forms... 4 00:00:21,840 --> 00:00:25,320 with intriguing social lives... 5 00:00:25,480 --> 00:00:28,600 ...and incredible intelligence. 6 00:00:28,760 --> 00:00:32,440 To reveal their secrets, a hidden team goes undercover. 7 00:00:32,600 --> 00:00:34,520 ♪ To reveal their secrets, a hidden team goes undercover. 8 00:00:34,680 --> 00:00:36,280 Spy Creatures. 9 00:00:40,560 --> 00:00:44,280 The most innovative undersea robots in the world. 10 00:00:48,360 --> 00:00:51,760 They not only look like the animals they film. 11 00:00:51,920 --> 00:00:54,680 They interact with them as no human can. 12 00:01:00,240 --> 00:01:02,200 Equipped with hidden cameras... 13 00:01:06,720 --> 00:01:09,400 ...they reveal their astonishing lives. 14 00:01:12,400 --> 00:01:16,600 As our spies join their undersea world... 15 00:01:16,760 --> 00:01:20,640 they shed light on some of the mysteries of the deep. 16 00:01:29,200 --> 00:01:32,800 As our spies search the ocean for intelligent life, 17 00:01:32,960 --> 00:01:34,480 they find ways of thinking 18 00:01:34,640 --> 00:01:37,160 that must be seen to be believed. 19 00:01:39,880 --> 00:01:42,960 A family of sperm whales, 20 00:01:43,120 --> 00:01:45,760 the most intelligent creatures in the ocean... 21 00:01:49,680 --> 00:01:53,120 ...and owners of the largest brains on the planet. 22 00:02:00,360 --> 00:02:04,800 These intellectual giants show a social intelligence 23 00:02:04,960 --> 00:02:06,560 that appears similar to our own. 24 00:02:13,160 --> 00:02:15,760 To gain insights into their minds, 25 00:02:15,920 --> 00:02:17,600 a spy is sent among them... 26 00:02:20,200 --> 00:02:24,440 ...an autonomous submersible programmed to follow the whales. 27 00:02:26,920 --> 00:02:29,240 At over 3 metres long, 28 00:02:29,400 --> 00:02:33,400 it's the same size as a newborn whale, 29 00:02:33,560 --> 00:02:37,040 large enough to hide an array of cameras... 30 00:02:40,840 --> 00:02:43,360 ...but small enough to arouse 31 00:02:43,520 --> 00:02:45,720 the maternal interest of a female. 32 00:02:50,280 --> 00:02:54,760 Her curiosity hints at what she may be thinking... 33 00:02:57,360 --> 00:03:01,080 ...a desire to reach out and make friends. 34 00:03:07,720 --> 00:03:10,720 Seen through the camera eye of our spy... 35 00:03:15,120 --> 00:03:17,520 ...a meeting with a sentient mind. 36 00:03:30,040 --> 00:03:32,800 A first contact 37 00:03:32,960 --> 00:03:35,600 with an inquisitive and questioning being. 38 00:03:42,800 --> 00:03:44,400 Our spy's hydrophones 39 00:03:44,560 --> 00:03:47,320 now capture something extraordinary... 40 00:03:53,080 --> 00:03:55,240 She attempts to communicate. 41 00:04:00,280 --> 00:04:02,680 Another sign of her social intelligence. 42 00:04:05,760 --> 00:04:08,920 She uses the same clicks when greeting other whales. 43 00:04:13,840 --> 00:04:15,400 Her open jaw means 44 00:04:15,560 --> 00:04:18,000 she's introducing herself to our spy. 45 00:04:37,160 --> 00:04:39,520 Waiting in the wings is a calf. 46 00:04:46,680 --> 00:04:49,040 In a touching sign of approval, 47 00:04:49,200 --> 00:04:51,880 she invites the youngster to meet our spy creature. 48 00:04:55,480 --> 00:04:58,240 An encounter far closer than ever imagined. 49 00:05:04,240 --> 00:05:07,280 The camera even reveals his hitchhiking companions. 50 00:05:13,280 --> 00:05:16,600 Harmless remora fish... enjoying a free ride. 51 00:05:27,040 --> 00:05:29,200 Our spy is gaining an insight 52 00:05:29,360 --> 00:05:32,000 into how relationships form among whales. 53 00:05:35,480 --> 00:05:38,880 Being allowed so close is a sign of acceptance. 54 00:05:44,080 --> 00:05:45,400 The mother is so trusting, 55 00:05:45,560 --> 00:05:48,680 she leaves her calf and heads to the ocean depths. 56 00:05:55,960 --> 00:05:58,440 She'll dive nearly 2 miles below... 57 00:06:02,320 --> 00:06:06,080 ...leaving a friend to look after her calf. 58 00:06:06,240 --> 00:06:10,760 Spy Whale seems to be welcome, too. 59 00:06:10,920 --> 00:06:12,680 Together, they'll stay with the calf 60 00:06:12,840 --> 00:06:14,560 until the mother returns. 61 00:06:17,720 --> 00:06:21,360 Our spy is now perfectly placed to discover more 62 00:06:21,520 --> 00:06:24,600 about the social intelligence of the whales. 63 00:06:33,760 --> 00:06:35,840 In the coral reefs of Indonesia, 64 00:06:36,000 --> 00:06:38,960 there are more intelligent life-forms to be found. 65 00:06:42,640 --> 00:06:45,960 The smartest of all is the coconut octopus. 66 00:06:48,360 --> 00:06:51,080 As well as a main brain in its body, 67 00:06:51,240 --> 00:06:53,800 each of its eight arms has a brain of its own. 68 00:06:59,320 --> 00:07:02,240 All nine brains can think for themselves, 69 00:07:02,400 --> 00:07:04,680 or even think as one when required. 70 00:07:12,000 --> 00:07:15,520 To help fathom it out, another spy is needed... 71 00:07:18,320 --> 00:07:21,000 ...one programmed to walk in a similar way. 72 00:07:24,800 --> 00:07:27,400 Its aim is to communicate with the octopus... 73 00:07:30,320 --> 00:07:32,720 ...to find out how clever it really is. 74 00:07:39,360 --> 00:07:41,280 What must he be thinking? 75 00:07:49,000 --> 00:07:51,000 Then, a clue. 76 00:07:58,280 --> 00:08:01,200 He's working out whether it's friend or a foe. 77 00:08:07,280 --> 00:08:10,360 It seems our spy is a friend. 78 00:08:15,440 --> 00:08:17,240 Just as well. 79 00:08:17,400 --> 00:08:19,320 He certainly has plenty of enemies. 80 00:08:24,920 --> 00:08:27,760 His soft body means everyone's out to get him. 81 00:08:34,720 --> 00:08:36,600 And not just him. 82 00:08:43,960 --> 00:08:45,920 Such dangers are small-fry 83 00:08:46,080 --> 00:08:48,000 compared with the oceans' top predators. 84 00:08:51,400 --> 00:08:54,480 Blacktip sharks hunt octopus. 85 00:08:57,880 --> 00:09:00,880 Fortunately, our spy doesn't smell like one. 86 00:09:03,720 --> 00:09:06,920 Not so, the real thing. 87 00:09:07,080 --> 00:09:09,240 He may hide, but they could still find him. 88 00:09:20,320 --> 00:09:23,480 Time for some quick thinking. 89 00:09:23,640 --> 00:09:26,080 A hollow bamboo shows promise. 90 00:09:36,880 --> 00:09:40,160 But its open entrance is far from ideal. 91 00:09:46,560 --> 00:09:49,160 Our spy may have the answer. 92 00:09:58,280 --> 00:10:00,400 It's just what the octopus needs. 93 00:10:09,760 --> 00:10:12,040 But will he dare take it from him? 94 00:10:30,840 --> 00:10:32,480 Like a seasoned thief, 95 00:10:32,640 --> 00:10:34,800 he tries to avoid raising suspicion. 96 00:10:39,200 --> 00:10:41,320 Being aware of what others could be thinking 97 00:10:41,480 --> 00:10:43,680 is a sign of deep intelligence. 98 00:11:09,600 --> 00:11:11,680 A perfect fit! 99 00:11:14,760 --> 00:11:16,560 And just in time! 100 00:11:31,200 --> 00:11:34,400 With nothing worth eating, the sharks move on. 101 00:11:39,840 --> 00:11:42,720 The coconut octopus need hide no more. 102 00:11:45,720 --> 00:11:49,200 As a sign of acceptance, he shows his true feelings. 103 00:11:53,840 --> 00:11:56,160 As their relationship grows, 104 00:11:56,320 --> 00:11:58,480 there'll be plenty more to discover. 105 00:12:06,560 --> 00:12:08,280 Of all seagoers, 106 00:12:08,440 --> 00:12:13,840 few are cleverer than these Thailand macaques. 107 00:12:14,000 --> 00:12:15,960 Spy Macaque is discovering 108 00:12:16,120 --> 00:12:18,520 how they survive on this remote island. 109 00:12:24,760 --> 00:12:27,400 It, too, has a camera in its eye. 110 00:12:33,080 --> 00:12:35,680 It can not only film above the surface, 111 00:12:35,840 --> 00:12:38,120 but underwater, too. 112 00:12:48,800 --> 00:12:50,760 As well as being able to swim, 113 00:12:50,920 --> 00:12:54,880 it has a fully waterproof camera eye, 114 00:12:55,040 --> 00:12:57,480 perfect for filming these free divers 115 00:12:57,640 --> 00:12:59,320 searching for shellfish. 116 00:13:07,000 --> 00:13:09,720 They can hold their breath for a minute or more. 117 00:13:22,320 --> 00:13:25,800 When they come up for air, there's more seafood to find. 118 00:13:31,960 --> 00:13:36,480 Our spy has acquired Spy Oyster. 119 00:13:36,640 --> 00:13:39,840 Together, they capture a filming first. 120 00:13:41,840 --> 00:13:45,160 These monkeys have gone fishing, 121 00:13:45,320 --> 00:13:47,480 grabbing whatever is trapped in the pools. 122 00:13:55,240 --> 00:13:57,360 It takes quick-witted reactions... 123 00:14:00,720 --> 00:14:03,040 ...and a firm grip. 124 00:14:14,880 --> 00:14:16,880 Fish course over, 125 00:14:17,040 --> 00:14:18,920 there's more seafood on the menu... 126 00:14:25,240 --> 00:14:29,520 ...oysters embedded in the rocks. 127 00:14:29,680 --> 00:14:33,800 They can't be removed by brute force alone. 128 00:14:33,960 --> 00:14:37,360 It's a task only the best minds can crack... 129 00:14:39,640 --> 00:14:41,520 ...those that can wield a tool. 130 00:14:47,880 --> 00:14:49,920 A treat worth the effort. 131 00:14:56,400 --> 00:14:58,680 Finding the right rock is a knack. 132 00:15:12,200 --> 00:15:14,480 It must be the correct weight and size. 133 00:15:18,040 --> 00:15:20,640 Like this one, designed for the job in hand. 134 00:15:25,560 --> 00:15:27,480 Even so, he must be careful. 135 00:15:30,160 --> 00:15:32,280 One slip could be nasty. 136 00:15:35,880 --> 00:15:39,280 It's the perfect tool... 137 00:15:39,440 --> 00:15:41,080 ...or was. 138 00:15:45,160 --> 00:15:47,320 Oh, well. 139 00:15:50,280 --> 00:15:54,120 Knowledge comes with experience. 140 00:15:54,280 --> 00:15:56,600 It starts with a sense of curiosity. 141 00:16:05,080 --> 00:16:06,960 But others are curious, too. 142 00:16:13,360 --> 00:16:15,600 Climbing with a spy cam isn't easy. 143 00:16:21,280 --> 00:16:24,640 Whoops! 144 00:16:24,800 --> 00:16:26,360 No bother. 145 00:16:26,520 --> 00:16:28,720 If you're smart, you know how to have fun. 146 00:16:42,920 --> 00:16:45,760 A chance to make friends and let off steam. 147 00:16:55,320 --> 00:16:57,120 As our spies found, 148 00:16:57,280 --> 00:16:59,800 macaques, cast away on a remote island, 149 00:16:59,960 --> 00:17:02,440 have found clever ways to adapt. 150 00:17:05,200 --> 00:17:09,440 Creative thinking can also be used to find a mate. 151 00:17:13,880 --> 00:17:15,600 In the Sea of Japan, 152 00:17:15,760 --> 00:17:18,880 there's even a sea creature who creates works of art. 153 00:17:22,760 --> 00:17:25,880 Spy Pufferfish is on a mission to find it. 154 00:17:31,400 --> 00:17:34,080 The artist in residence won't be found among the coral. 155 00:17:36,560 --> 00:17:40,480 It needs a blank canvas to work with... 156 00:17:40,640 --> 00:17:43,440 something only the sand provides. 157 00:17:47,720 --> 00:17:50,160 And here it is, 158 00:17:50,320 --> 00:17:54,760 An exquisite sand sculpture found nowhere else on earth. 159 00:18:13,320 --> 00:18:16,840 The artist at work is a male Japanese pufferfish. 160 00:18:25,160 --> 00:18:28,000 He's designed his masterpiece to lure in a mate. 161 00:18:35,520 --> 00:18:39,080 An artistic creation to delight a female's eye. 162 00:18:47,640 --> 00:18:49,840 He uses a fin to plough a furrow... 163 00:18:52,960 --> 00:18:55,720 ...while other fins sweep the sand into ridges. 164 00:18:59,840 --> 00:19:03,160 The gullies channel the finest particles towards the centre. 165 00:19:08,280 --> 00:19:12,840 The result is a fully functional work of art. 166 00:19:13,000 --> 00:19:14,920 It's now Spy Puffer's turn. 167 00:19:30,160 --> 00:19:32,640 Artworks are best viewed at a distance. 168 00:19:42,200 --> 00:19:44,320 Oh, dear. 169 00:19:49,240 --> 00:19:51,800 Nothing compares to the true artist. 170 00:20:00,120 --> 00:20:01,960 The female will decide. 171 00:20:05,080 --> 00:20:08,120 Spy Puffer's creation is hardly worth a second look. 172 00:20:13,040 --> 00:20:15,000 She's after a masterpiece. 173 00:20:21,800 --> 00:20:24,120 But for this discerning art critic, 174 00:20:24,280 --> 00:20:26,040 there's still room for improvement... 175 00:20:29,320 --> 00:20:31,960 ...especially when some debris spoils the design... 176 00:20:34,560 --> 00:20:37,200 ...a blemish easily dealt with by the male. 177 00:20:44,920 --> 00:20:49,360 But it still needs some finishing touches, 178 00:20:49,520 --> 00:20:52,480 such as shells to decorate the ridges. 179 00:20:57,920 --> 00:21:00,320 They're more than an artistic flourish. 180 00:21:00,480 --> 00:21:02,320 They stabilise the ridges, 181 00:21:02,480 --> 00:21:04,880 slowing the water that might stir the centre... 182 00:21:07,960 --> 00:21:11,360 ...for this is where the female will lay her eggs. 183 00:21:13,280 --> 00:21:15,440 But the male has run out of shells, 184 00:21:15,600 --> 00:21:17,960 and the female is losing interest. 185 00:21:21,880 --> 00:21:24,560 Spy Puffer becomes the artist's assistant. 186 00:21:33,760 --> 00:21:35,600 The finishing touch he needs. 187 00:21:48,960 --> 00:21:51,440 All this striving for artistic perfection 188 00:21:51,600 --> 00:21:53,320 is a test of his fitness. 189 00:21:58,800 --> 00:22:01,600 Satisfied with the aesthetic details, 190 00:22:01,760 --> 00:22:03,680 the female enters the nest. 191 00:22:09,080 --> 00:22:11,480 They join together, cheek-to-cheek. 192 00:22:17,880 --> 00:22:19,520 Then, quick as a flash, 193 00:22:19,680 --> 00:22:22,080 the eggs are laid and fertilised. 194 00:22:26,480 --> 00:22:28,600 With a little help from Spy Puffer, 195 00:22:28,760 --> 00:22:31,880 the next generation of artists is secure. 196 00:22:38,520 --> 00:22:40,920 While pufferfish think creatively, 197 00:22:41,080 --> 00:22:44,640 fish shoals all think together. 198 00:22:44,800 --> 00:22:48,440 They show swarm intelligence, moving as one 199 00:22:48,600 --> 00:22:51,080 as they mirror the moves of their nearest neighbours. 200 00:22:56,280 --> 00:23:00,240 Their group thinking is about to be tested by smarter minds. 201 00:23:03,880 --> 00:23:06,720 Marlin... 202 00:23:06,880 --> 00:23:09,440 one of the ocean's fastest predators. 203 00:23:11,640 --> 00:23:16,560 They use teamwork to drive mackerel up from the depths, 204 00:23:16,720 --> 00:23:21,480 forcing them to the surface in ever-tighter balls. 205 00:23:21,640 --> 00:23:24,240 They are not alone. 206 00:23:24,400 --> 00:23:26,440 Sea lions soon join the gathering. 207 00:23:30,240 --> 00:23:34,120 Among them is a new spy creature-- 208 00:23:34,280 --> 00:23:37,800 Spy Sea Lion. 209 00:23:37,960 --> 00:23:39,520 Like the real thing, 210 00:23:39,680 --> 00:23:42,880 its flexible body lets it manoeuvre among the shoals. 211 00:23:52,640 --> 00:23:55,240 Its eye cams gain a sea lion's view 212 00:23:55,400 --> 00:23:57,360 as the marlin spear their prey. 213 00:24:03,280 --> 00:24:04,920 Like master swordsmen, 214 00:24:05,080 --> 00:24:07,960 they use their metre-long bills as deadly weapons. 215 00:24:15,280 --> 00:24:19,280 As the hunt continues, our spy films an insider's view. 216 00:24:23,360 --> 00:24:25,320 It won't be working alone. 217 00:24:27,400 --> 00:24:30,720 As frigate birds gather, another spy joins... 218 00:24:33,760 --> 00:24:36,680 ...one that captures the marlins' skills from the air. 219 00:24:43,120 --> 00:24:46,840 They corral the shoal, concentrating the ball, 220 00:24:47,000 --> 00:24:49,600 letting them pick off the fish on the outside. 221 00:24:52,240 --> 00:24:54,000 But they don't have it all their own way. 222 00:24:57,760 --> 00:24:59,920 The marlin will soon be competing 223 00:25:00,080 --> 00:25:02,800 with those with far greater intelligence. 224 00:25:07,560 --> 00:25:10,520 Spy Sea Lion now has plenty of company. 225 00:25:13,000 --> 00:25:15,680 They are here in their hundreds. 226 00:25:20,800 --> 00:25:22,200 Working together, 227 00:25:22,360 --> 00:25:24,760 they steal the bait ball from the marlin. 228 00:25:29,000 --> 00:25:32,880 Seen through the camera eye of our spy, 229 00:25:33,040 --> 00:25:36,800 our spy reveals what happens once the sea lions take over. 230 00:25:39,480 --> 00:25:42,280 It joins them as they unite to split the ball... 231 00:25:45,720 --> 00:25:49,400 ...capturing a sea lion's view from inside the shoal. 232 00:25:52,200 --> 00:25:54,680 It shows how the fish move as one. 233 00:26:00,720 --> 00:26:02,400 Its swarm intelligence 234 00:26:02,560 --> 00:26:04,440 pitched against that of the sea lions'. 235 00:26:07,600 --> 00:26:10,480 This is where true intelligence shows its worth. 236 00:26:13,960 --> 00:26:17,400 They work together to force the shoal apart. 237 00:26:17,560 --> 00:26:19,880 They can now pick off the weak and injured. 238 00:26:24,560 --> 00:26:28,000 Sea lions can eat 15 kilos of fish a day. 239 00:26:31,760 --> 00:26:35,360 But such a colossal bait ball is too much, even for them. 240 00:26:38,320 --> 00:26:40,920 They start to play with their food rather than eat it. 241 00:26:46,480 --> 00:26:48,560 Then, something unexpected. 242 00:26:54,760 --> 00:26:57,520 They gift the leftovers to the hungry marlin. 243 00:27:05,400 --> 00:27:07,560 There's even a fish for Spy Sea Lion. 244 00:27:16,200 --> 00:27:19,760 Not much use to our spy. 245 00:27:19,920 --> 00:27:21,920 It is to the marlin. 246 00:27:25,320 --> 00:27:30,040 The sea lions may have outsmarted swarm intelligence, 247 00:27:30,200 --> 00:27:32,680 but even they can be beaten by a bigger power. 248 00:27:40,320 --> 00:27:43,920 A Bryde's whale will make short work of what they've left. 249 00:27:54,600 --> 00:27:57,040 Back on the reef, there are more insights 250 00:27:57,200 --> 00:27:59,360 to be gained from the coconut octopus. 251 00:28:09,160 --> 00:28:12,760 Spy Octopus is still nurturing its newfound relationship. 252 00:28:22,600 --> 00:28:24,880 Their bond has only grown stronger. 253 00:28:29,800 --> 00:28:32,120 To feed, he must leave his hideaway. 254 00:28:41,680 --> 00:28:44,600 As a precaution, he takes the coconut shell with him. 255 00:28:54,080 --> 00:28:56,520 What was once the door to his refuge 256 00:28:56,680 --> 00:28:58,520 is now a mobile home. 257 00:29:15,280 --> 00:29:17,360 But there are more surprises in store. 258 00:29:19,680 --> 00:29:24,440 The octopus is still looking to improve his security. 259 00:29:24,600 --> 00:29:27,560 Some armour plating wouldn't go amiss. 260 00:29:31,400 --> 00:29:33,360 A shell would be perfect. 261 00:29:47,280 --> 00:29:49,920 His only problem is carrying it all. 262 00:30:03,480 --> 00:30:06,120 This is taking defence seriously. 263 00:30:13,400 --> 00:30:14,960 All bases covered, 264 00:30:15,120 --> 00:30:17,520 he's perfectly placed to stage an ambush. 265 00:30:26,960 --> 00:30:28,960 And what better than a crab? 266 00:30:32,080 --> 00:30:34,240 The chase is on! 267 00:30:38,400 --> 00:30:41,000 But the crab has a trick of its own. 268 00:30:41,160 --> 00:30:43,760 it heads to the surface. 269 00:30:43,920 --> 00:30:46,280 So does the octopus. 270 00:30:53,800 --> 00:30:55,800 He makes a grab! 271 00:31:03,400 --> 00:31:06,200 It's firmly in his grasp, but he must eat quickly. 272 00:31:09,880 --> 00:31:11,960 He's being watched. 273 00:31:13,840 --> 00:31:16,040 A rival coconut octopus. 274 00:31:19,160 --> 00:31:21,160 His colour change shows he means business. 275 00:31:28,560 --> 00:31:31,000 To up the ante, he makes himself bigger. 276 00:31:35,760 --> 00:31:39,800 But the octopus stands his ground... 277 00:31:39,960 --> 00:31:42,360 before firing a salvo of shells. 278 00:31:47,160 --> 00:31:49,400 He retreats to his fortified home... 279 00:31:54,320 --> 00:31:57,640 ...and grabs a discarded paint lid to act as a shield. 280 00:32:04,000 --> 00:32:07,400 He's now ready for anything... 281 00:32:07,560 --> 00:32:10,400 including taking the paint lid with him. 282 00:32:29,840 --> 00:32:31,640 One last challenge... 283 00:32:34,280 --> 00:32:36,080 ...but soon seen off. 284 00:32:38,760 --> 00:32:40,480 That's how he treats his enemies. 285 00:32:50,320 --> 00:32:52,440 This is how he treats his friends. 286 00:33:13,120 --> 00:33:15,000 Few are as clever, 287 00:33:15,160 --> 00:33:17,400 but for organisational skills, 288 00:33:17,560 --> 00:33:19,480 he has serious competition. 289 00:33:23,720 --> 00:33:26,240 In the tropical paradise of Belize, 290 00:33:26,400 --> 00:33:28,960 the hermit crabs have a problem. 291 00:33:34,640 --> 00:33:38,240 They've outgrown their homes... 292 00:33:38,400 --> 00:33:40,880 ...or their shells have become worse for wear. 293 00:33:47,480 --> 00:33:50,040 They need to upsize their accommodation. 294 00:33:52,680 --> 00:33:55,520 And a new home has just come on the market. 295 00:34:02,360 --> 00:34:04,320 Those interested start measuring up. 296 00:34:09,200 --> 00:34:11,080 This one certainly has potential. 297 00:34:19,920 --> 00:34:22,040 But others, too, are showing interest... 298 00:34:28,200 --> 00:34:30,280 ...even squabbling over who should move in. 299 00:34:34,040 --> 00:34:35,960 For some, it's too big. 300 00:34:36,120 --> 00:34:39,040 For others, it's too small. 301 00:34:39,200 --> 00:34:40,800 To resolve the issue, 302 00:34:40,960 --> 00:34:43,800 they must stop squabbling and cooperate. 303 00:34:49,920 --> 00:34:53,520 To find out how, another spy goes undercover... 304 00:34:57,600 --> 00:35:00,320 ...one with a camera in its shell. 305 00:35:04,680 --> 00:35:07,000 It's arrived at the perfect moment. 306 00:35:13,240 --> 00:35:17,560 The crabs line up in order of size. 307 00:35:17,720 --> 00:35:20,160 They don't all need grand accommodation. 308 00:35:22,560 --> 00:35:26,600 They just need the next size up. 309 00:35:26,760 --> 00:35:29,880 First, they must find their correct place in the queue. 310 00:35:38,640 --> 00:35:40,560 They wait until everyone is assembled. 311 00:35:45,040 --> 00:35:47,120 Then the house swap begins. 312 00:35:49,160 --> 00:35:51,120 The largest leaves his old home 313 00:35:51,280 --> 00:35:53,640 and moves into the vacant shell next door. 314 00:35:56,240 --> 00:36:00,720 Then the next size down takes over the shell he left behind. 315 00:36:00,880 --> 00:36:03,600 And so it goes on, in order of size. 316 00:36:15,160 --> 00:36:17,240 Most are content with their new home... 317 00:36:19,680 --> 00:36:21,800 ...although one seems to have house envy. 318 00:36:25,520 --> 00:36:27,960 He's eyeing up our spy. 319 00:36:31,360 --> 00:36:34,160 He just needs to check the shell for size. 320 00:36:46,480 --> 00:36:49,520 It meets his requirements, so he doesn't waste time. 321 00:36:55,360 --> 00:36:58,080 But this home comes with responsibilities... 322 00:37:01,680 --> 00:37:03,760 ...ones that involve filming, too. 323 00:37:17,320 --> 00:37:20,080 But our new spy seems to be having second thoughts. 324 00:37:23,440 --> 00:37:27,360 His old shell was a better fit after all. 325 00:37:27,520 --> 00:37:30,400 He'll keep it for a little longer. 326 00:37:38,520 --> 00:37:41,680 Our spy is now the only crab left homeless. 327 00:37:46,600 --> 00:37:51,680 The Caribbean is home to yet more clever minds. 328 00:37:51,840 --> 00:37:56,160 This tiny island in the Bahamas has been colonised by wild pigs. 329 00:37:59,240 --> 00:38:02,080 They spend much of their day just above the tide line. 330 00:38:08,880 --> 00:38:11,960 To discover how they survive on this remote island, 331 00:38:12,120 --> 00:38:14,480 Spy Piglet joins the team. 332 00:38:20,680 --> 00:38:23,880 Pigs are highly intelligent and sociable animals. 333 00:38:29,480 --> 00:38:31,920 So a new pig soon piques their interest. 334 00:38:39,720 --> 00:38:41,960 Nudging snouts is a friendly gesture. 335 00:38:44,680 --> 00:38:45,960 A promising start. 336 00:38:50,240 --> 00:38:52,920 Introductions over, they head to the sea. 337 00:38:57,960 --> 00:39:00,800 The pigs' daily ritual begins. 338 00:39:11,680 --> 00:39:14,440 To find out why they enjoy swimming so much, 339 00:39:14,600 --> 00:39:18,000 Spy Pig is soon hot on their curly tails. 340 00:39:20,640 --> 00:39:23,440 What better way to find out what's going on? 341 00:39:29,200 --> 00:39:31,320 It's clear that they are expert swimmers. 342 00:39:36,040 --> 00:39:37,840 And even here they're sociable, too. 343 00:39:45,880 --> 00:39:47,840 Our spy gets another greeting. 344 00:40:07,920 --> 00:40:10,240 Pigs were brought to the island in the '50s, 345 00:40:10,400 --> 00:40:12,280 surviving on crabs and berries 346 00:40:12,440 --> 00:40:16,040 or whatever else they could find. 347 00:40:16,200 --> 00:40:19,520 As numbers grew, they looked to the ocean for a meal. 348 00:40:24,360 --> 00:40:26,960 Tourism brought new opportunities. 349 00:40:29,600 --> 00:40:32,960 Each day, boats bringing food would visit them. 350 00:40:36,680 --> 00:40:41,120 Until the sound of outboards became their dinner bell. 351 00:40:41,280 --> 00:40:44,480 As word got around, more boats arrived, 352 00:40:44,640 --> 00:40:47,760 until the pigs' daily excursions became a way of life. 353 00:40:52,080 --> 00:40:54,400 A banquet for all. 354 00:41:03,840 --> 00:41:05,520 They may be social creatures, 355 00:41:05,680 --> 00:41:08,800 but manners are forgotten when mealtime arrives. 356 00:41:14,720 --> 00:41:17,320 Now it's every pig for itself. 357 00:41:20,520 --> 00:41:24,040 And not just pigs. 358 00:41:24,200 --> 00:41:27,040 Gulls know when it's feeding time, too. 359 00:41:37,680 --> 00:41:42,120 The pigs' intelligence created this tourist attraction. 360 00:41:42,280 --> 00:41:44,200 But it doesn't take a genius 361 00:41:44,360 --> 00:41:46,040 to know when all the food is gone. 362 00:42:02,560 --> 00:42:04,600 The search for intelligent life 363 00:42:04,760 --> 00:42:08,000 is taking our spy creatures to many ocean realms. 364 00:42:10,760 --> 00:42:12,760 But it's the reefs that provide shelter 365 00:42:12,920 --> 00:42:17,800 for a quarter of all marine life. 366 00:42:17,960 --> 00:42:21,000 Amongst all this abundance is Spy Crab. 367 00:42:24,680 --> 00:42:28,120 Beyond the reef is our spy's subject of interest. 368 00:42:33,040 --> 00:42:35,880 Fish that have found a way to keep safe, 369 00:42:36,040 --> 00:42:39,000 away from the protection of the reef. 370 00:42:47,840 --> 00:42:52,720 Our undercover crustacean will find out how they do it. 371 00:42:52,880 --> 00:42:56,520 The fish in question are saddleback clownfish. 372 00:42:56,680 --> 00:43:00,120 They use carpet anemones as their fortress and home. 373 00:43:03,440 --> 00:43:07,080 Its tentacles are laced with a deadly toxin. 374 00:43:07,240 --> 00:43:11,360 But the clownfish have acquired immunity. 375 00:43:11,520 --> 00:43:13,480 No predators dare come near. 376 00:43:18,200 --> 00:43:20,880 In return, the clownfish all muck in 377 00:43:21,040 --> 00:43:23,160 to keep the anemone spick-and-span. 378 00:43:30,040 --> 00:43:31,800 To raise a family, 379 00:43:31,960 --> 00:43:35,360 they need somewhere safe to lay their eggs. 380 00:43:35,520 --> 00:43:38,200 A bed of poison is hardly a nursery. 381 00:43:44,240 --> 00:43:47,840 So a search party sets off to find something more suitable... 382 00:43:51,040 --> 00:43:53,920 ...with Spy Crab following on behind. 383 00:43:59,120 --> 00:44:01,400 Plastics are the scourge of the ocean, 384 00:44:01,560 --> 00:44:05,280 but clownfish are keen on recycling. 385 00:44:05,440 --> 00:44:09,160 A flip-flop would make an ideal egg nursery, 386 00:44:09,320 --> 00:44:11,320 if only they could bring it back home. 387 00:44:28,160 --> 00:44:30,080 Even the enterprising clownfish 388 00:44:30,240 --> 00:44:32,240 have no use for a plastic bottle. 389 00:44:35,160 --> 00:44:37,600 They dispatch it as quickly as they can. 390 00:44:49,840 --> 00:44:51,920 They need something more sustainable. 391 00:44:55,160 --> 00:44:58,000 Another job for Spy Octopus. 392 00:45:09,560 --> 00:45:12,360 It has an environmentally friendly solution. 393 00:45:17,120 --> 00:45:19,480 Just what they were looking for! 394 00:45:27,640 --> 00:45:30,200 In an astonishing display of teamwork, 395 00:45:30,360 --> 00:45:32,720 they take the coconut shell to the anemone. 396 00:45:37,560 --> 00:45:40,000 Among fish, such close cooperation 397 00:45:40,160 --> 00:45:42,240 has rarely been filmed. 398 00:45:49,160 --> 00:45:51,080 But they have more work to do. 399 00:45:55,280 --> 00:45:57,600 A little wash and brush-up is needed. 400 00:46:00,720 --> 00:46:03,480 Let egg-laying begin. 401 00:46:16,960 --> 00:46:19,120 A nursery, at last. 402 00:46:31,760 --> 00:46:33,720 The male will tend the eggs, 403 00:46:33,880 --> 00:46:35,760 keeping them clean and well-aerated. 404 00:46:40,680 --> 00:46:45,480 A week later, their young are ready to emerge, 405 00:46:45,640 --> 00:46:50,240 the reward for the clownfishes' close cooperation, 406 00:46:50,400 --> 00:46:53,520 one where Spy Octopus played a part. 407 00:47:00,960 --> 00:47:02,600 As our spies discovered, 408 00:47:02,760 --> 00:47:05,800 sea creatures have many unique ways of thinking. 409 00:47:09,320 --> 00:47:13,240 But none match the intelligence of the biggest brains of all. 410 00:47:17,360 --> 00:47:20,120 Spy Sperm Whale was left on babysitting duties. 411 00:47:23,000 --> 00:47:27,000 It's now keeping watch on an increasingly restless calf. 412 00:47:30,040 --> 00:47:33,640 Another of its cameras reveals why he's excited. 413 00:47:35,600 --> 00:47:38,120 Below, his mother is returning. 414 00:47:40,840 --> 00:47:43,880 She's been away for many hours, and her calf is hungry. 415 00:47:47,840 --> 00:47:49,800 He's heard his mother's unique call. 416 00:47:54,240 --> 00:47:56,520 Spy Whale follows close behind... 417 00:48:00,160 --> 00:48:02,120 ...even into the depths. 418 00:48:05,760 --> 00:48:08,600 Here, our spy captures the moment 419 00:48:08,760 --> 00:48:12,480 the mother positions herself vertically to feed her calf. 420 00:48:19,120 --> 00:48:22,200 Finally, he finds the spot. 421 00:48:22,360 --> 00:48:25,600 Only now does his mother release her milk. 422 00:48:30,720 --> 00:48:32,240 Instead of suckling, 423 00:48:32,400 --> 00:48:35,280 the calf drinks the milk as it flows into the water. 424 00:48:37,560 --> 00:48:39,840 It's so rich, even diluted, 425 00:48:40,000 --> 00:48:42,120 he only needs a little to be satisfied. 426 00:48:46,520 --> 00:48:50,440 Then his mother does something surprising. 427 00:48:50,600 --> 00:48:54,320 She positions herself the other way up 428 00:48:54,480 --> 00:48:57,200 and claps the water with her tail. 429 00:49:13,760 --> 00:49:18,200 Each slap is a signal that carries for many kilometres... 430 00:49:22,320 --> 00:49:26,000 ...one heard by families from far and wide. 431 00:49:52,440 --> 00:49:55,520 For the mother and calf, it's a special moment. 432 00:50:07,400 --> 00:50:10,520 A family reunion that has rarely been filmed. 433 00:50:13,920 --> 00:50:16,440 One that includes our very own spy. 434 00:50:20,840 --> 00:50:23,120 From deep in the heart of the family, 435 00:50:23,280 --> 00:50:26,240 it now bears witness to something extraordinary. 436 00:50:31,200 --> 00:50:34,520 Siblings, cousins, aunts, and grandmothers 437 00:50:34,680 --> 00:50:37,200 join together in a rare social event. 438 00:50:40,400 --> 00:50:42,960 A meeting of intelligent minds. 439 00:50:48,400 --> 00:50:53,200 But are their thoughts ones we might recognise? 440 00:50:53,360 --> 00:50:57,800 For they share the brain cells that help make us human-- 441 00:50:57,960 --> 00:50:59,360 specialised neurons 442 00:50:59,520 --> 00:51:02,480 that give us language, empathy, and culture. 443 00:51:04,720 --> 00:51:06,720 They have more of these human-like cells 444 00:51:06,880 --> 00:51:10,120 than any animal on Earth. 445 00:51:10,280 --> 00:51:12,320 It seems they are deep in conversation. 446 00:51:14,640 --> 00:51:16,800 Within this incredible gathering, 447 00:51:16,960 --> 00:51:18,520 information is exchanged 448 00:51:18,680 --> 00:51:21,080 and bonds of friendship are strengthened. 449 00:51:24,400 --> 00:51:27,280 This rare event lasts only a few minutes 450 00:51:27,440 --> 00:51:30,280 before each group goes its separate ways. 451 00:51:35,200 --> 00:51:39,680 For now, our spy is still deep in their midst. 452 00:51:51,720 --> 00:51:54,680 Next time, our spies reveal the deep feelings 453 00:51:54,840 --> 00:51:59,520 found among the creatures of the ocean... 454 00:51:59,680 --> 00:52:03,000 to discover the origins of our own emotions.