1 00:00:02,000 --> 00:00:05,300 The animal world is full of spectacle and wonder. 2 00:00:07,300 --> 00:00:10,140 But what's it like to be right in the heart of the action? 3 00:00:12,060 --> 00:00:16,140 To find out, our team of spy creatures goes undercover. 4 00:00:18,460 --> 00:00:22,740 They not only look like the animals they film - 5 00:00:22,740 --> 00:00:24,740 they behave like them, too. 6 00:00:30,020 --> 00:00:32,780 Armed with the latest camera technology... 7 00:00:35,100 --> 00:00:37,820 ..they are heading across the globe. 8 00:00:43,620 --> 00:00:45,740 From the heat of the tropics... 9 00:00:48,860 --> 00:00:51,300 ..to the lands that lie in the north. 10 00:00:54,500 --> 00:00:57,180 From the islands of the southern seas... 11 00:01:00,500 --> 00:01:03,260 ..to the snow and ice of the frozen poles... 12 00:01:05,980 --> 00:01:09,300 ..our spies reveal the astonishing variety of life 13 00:01:09,300 --> 00:01:12,060 that thrives there 14 00:01:12,060 --> 00:01:13,740 from inside their world. 15 00:01:22,460 --> 00:01:24,860 On this assignment, our spy creatures 16 00:01:24,860 --> 00:01:27,700 explore life in the temperate zone - 17 00:01:27,700 --> 00:01:29,740 the lands that lie between the tropics 18 00:01:29,740 --> 00:01:31,340 and the Arctic Circle. 19 00:01:36,660 --> 00:01:38,300 In this northern realm, 20 00:01:38,300 --> 00:01:40,900 animals find extraordinary ways to cope 21 00:01:40,900 --> 00:01:42,580 with the changing seasons 22 00:01:42,580 --> 00:01:45,620 and the surprising opportunities they bring. 23 00:01:47,460 --> 00:01:50,700 In the mountains of Japan, winters can be harsh 24 00:01:50,700 --> 00:01:53,300 and temperatures can fall far below zero. 25 00:01:58,220 --> 00:01:59,700 The Japanese macaque 26 00:01:59,700 --> 00:02:03,020 is the only monkey that can survive this far north. 27 00:02:06,460 --> 00:02:10,580 Here, volcanic springs bring comforting warmth. 28 00:02:10,580 --> 00:02:11,980 A mountain spa. 29 00:02:14,460 --> 00:02:16,660 The perfect spot to luxuriate. 30 00:02:20,540 --> 00:02:23,420 A new member has just joined their health club. 31 00:02:24,820 --> 00:02:27,420 Spy Macaque is already making friends. 32 00:02:34,260 --> 00:02:36,980 A youngster, just nine months old. 33 00:02:48,140 --> 00:02:49,940 The spa has another new recruit. 34 00:02:57,740 --> 00:03:00,900 One that can film the monkeys' bathing rituals 35 00:03:00,900 --> 00:03:03,980 both from above and below. 36 00:03:07,460 --> 00:03:10,380 It's already capturing unique behaviour. 37 00:03:11,700 --> 00:03:14,380 As a mother grooms her baby, 38 00:03:14,380 --> 00:03:17,300 she lets warm water penetrate deep into its fur. 39 00:03:23,700 --> 00:03:25,220 The hot tub is a place 40 00:03:25,220 --> 00:03:28,060 to socialise and strengthen friendships. 41 00:03:31,260 --> 00:03:33,060 It's a shared activity. 42 00:03:33,060 --> 00:03:36,500 You scratch my back, I'll scratch yours. 43 00:03:38,940 --> 00:03:41,180 The troupe has a clear hierarchy. 44 00:03:41,180 --> 00:03:44,620 Who grooms who helps keep everyone in their place. 45 00:03:50,100 --> 00:03:52,100 It's also a chance to relax. 46 00:04:00,100 --> 00:04:02,820 Nearby, winter sports are on offer. 47 00:04:05,860 --> 00:04:08,380 The young males love play fighting. 48 00:04:08,380 --> 00:04:10,580 MACAQUES SCREECH 49 00:04:12,060 --> 00:04:15,060 One day they'll leave the troupe to join another. 50 00:04:15,060 --> 00:04:18,100 Testing their strength helps prepare them for that moment. 51 00:04:29,940 --> 00:04:34,380 Today, they have a chance to play with a snowball. 52 00:04:34,380 --> 00:04:35,740 One that can film. 53 00:04:46,380 --> 00:04:50,420 Rather than play, he admires his reflection in its lens. 54 00:04:54,500 --> 00:04:56,700 Nearby, games are almost over. 55 00:05:05,300 --> 00:05:10,540 In the spa, Spy Monkey is still making friends, 56 00:05:10,540 --> 00:05:12,580 including the curious baby. 57 00:05:26,020 --> 00:05:28,220 But when social position is everything, 58 00:05:28,220 --> 00:05:32,020 you can't always choose who your friends are. 59 00:05:32,020 --> 00:05:34,100 It's Mum who decides. 60 00:05:40,780 --> 00:05:42,900 The spa not only gives warmth, 61 00:05:42,900 --> 00:05:45,820 it gives therapy, 62 00:05:45,820 --> 00:05:47,500 helping them de-stress. 63 00:05:51,140 --> 00:05:53,260 It's used most by the females, 64 00:05:53,260 --> 00:05:55,820 especially those who are pregnant. 65 00:05:57,300 --> 00:05:59,740 As females never leave the troupe, 66 00:05:59,740 --> 00:06:03,220 they pass the custom down through the generations. 67 00:06:05,660 --> 00:06:09,060 The troupe's young males will soon be gone. 68 00:06:09,060 --> 00:06:12,500 For now, a favourite pastime is disturbing the peace. 69 00:06:27,740 --> 00:06:31,180 The baby isn't so quick off the mark. 70 00:06:31,180 --> 00:06:33,300 And Mum is nowhere to be seen. 71 00:06:45,620 --> 00:06:48,140 But what mother would ever really leave her baby? 72 00:06:58,860 --> 00:07:02,060 Now, a special kind of warmth. 73 00:07:02,060 --> 00:07:04,060 One only a mother can offer. 74 00:07:12,020 --> 00:07:14,420 But there goes her chance to relax. 75 00:07:20,140 --> 00:07:22,540 While it's still winter in Japan, 76 00:07:22,540 --> 00:07:25,020 the mountains of northwest Mexico 77 00:07:25,020 --> 00:07:27,780 are having their first taste of spring. 78 00:07:29,060 --> 00:07:30,780 It's the setting for perhaps 79 00:07:30,780 --> 00:07:33,340 the most beautiful wildlife spectacle of all. 80 00:07:34,500 --> 00:07:37,380 One that requires a unique spy creature. 81 00:07:38,460 --> 00:07:42,700 The blue-throated hummingbird is native to these forests. 82 00:07:42,700 --> 00:07:45,980 This spy version hovers just like the real thing. 83 00:07:47,780 --> 00:07:50,420 In the heart of this grove, 84 00:07:50,420 --> 00:07:53,820 half a billion monarch butterflies lie sleeping. 85 00:07:59,380 --> 00:08:01,380 They have travelled from as far as Canada 86 00:08:01,380 --> 00:08:03,780 to escape the cold northern winter. 87 00:08:06,500 --> 00:08:10,820 How they return to this exact spot is a mystery. 88 00:08:10,820 --> 00:08:14,500 Like the butterflies, hummingbirds feed on nectar. 89 00:08:14,500 --> 00:08:16,500 So our spy isn't seen as a threat. 90 00:08:18,100 --> 00:08:19,860 While resting, 91 00:08:19,860 --> 00:08:21,780 they cluster together 92 00:08:21,780 --> 00:08:24,340 to conserve precious warmth. 93 00:08:24,340 --> 00:08:25,860 But as winter ends, 94 00:08:25,860 --> 00:08:28,180 the sun warms their fragile wings. 95 00:08:32,460 --> 00:08:36,500 Once they reach a critical 13 degrees Celsius, 96 00:08:36,500 --> 00:08:38,020 they start to fly. 97 00:08:43,900 --> 00:08:45,860 As the day warms, 98 00:08:45,860 --> 00:08:47,380 the forest comes to life. 99 00:08:53,300 --> 00:08:56,500 Spy Hummingbird won't harm these delicate butterflies. 100 00:09:00,100 --> 00:09:03,740 Its moving parts are shielded to keep them safe. 101 00:09:04,780 --> 00:09:07,180 Butterflies can even safely land on its wings. 102 00:09:21,820 --> 00:09:25,260 It soon captures something quite extraordinary. 103 00:09:32,620 --> 00:09:35,900 What starts as a trickle soon becomes a stream. 104 00:09:43,340 --> 00:09:45,780 Then grows into a cascade. 105 00:09:53,740 --> 00:09:56,540 A spectacle that has rarely been filmed. 106 00:10:00,500 --> 00:10:04,060 And our spy is harmlessly in the very heart of it. 107 00:10:21,140 --> 00:10:24,260 Beauty also lies in the detail. 108 00:11:06,980 --> 00:11:09,860 After five months spent hibernating, 109 00:11:09,860 --> 00:11:11,900 each monarch must take a drink. 110 00:11:15,180 --> 00:11:18,620 It will convert their fat stores to vital sugars. 111 00:11:21,100 --> 00:11:23,380 Fuel for the long journey that lies ahead. 112 00:11:37,980 --> 00:11:41,100 Re-energized, they begin their migration 113 00:11:41,100 --> 00:11:42,740 back to North America. 114 00:11:54,500 --> 00:11:58,420 The journey will involve three successive generations, 115 00:11:58,420 --> 00:12:01,060 each completing a new stage of the journey. 116 00:12:04,140 --> 00:12:06,940 Only the last will return in the autumn. 117 00:12:10,260 --> 00:12:13,220 It's a relay race across the generations 118 00:12:13,220 --> 00:12:15,380 of up to 6,000 miles. 119 00:12:18,980 --> 00:12:22,980 How they return to this exact same grove remains a mystery. 120 00:12:33,780 --> 00:12:37,060 In Alaska, at the other end of North America, 121 00:12:37,060 --> 00:12:39,860 spring is only just starting to arrive. 122 00:12:47,980 --> 00:12:50,620 Here, bald eagles rule the skies. 123 00:12:53,460 --> 00:12:56,140 Including, for now, a spy. 124 00:13:01,020 --> 00:13:04,060 At this time of year, the glaciers are volatile, 125 00:13:04,060 --> 00:13:06,660 bringing danger to the life that thrives here. 126 00:13:09,380 --> 00:13:11,780 As the sun rises higher each day, 127 00:13:11,780 --> 00:13:13,580 the spring melt begins. 128 00:13:17,060 --> 00:13:19,780 Already, cracks have started to form. 129 00:13:23,780 --> 00:13:26,060 Soon the sea ice will be gone. 130 00:13:32,900 --> 00:13:37,540 The resident harbour seals now haul out on ice cast from a glacier. 131 00:13:44,260 --> 00:13:47,700 With spring, humpback whales also start to arrive. 132 00:13:54,620 --> 00:13:56,860 They migrated north from California 133 00:13:56,860 --> 00:13:59,860 to enjoy the feeding opportunities now found here. 134 00:14:07,340 --> 00:14:11,300 Sea otters gather in huge rafts - 135 00:14:11,300 --> 00:14:13,300 up to 2,000 in all. 136 00:14:25,100 --> 00:14:28,700 The nursing mothers congregate in the areas now free of ice. 137 00:14:39,020 --> 00:14:42,140 Spy Sea Otter joins them in their floating nursery. 138 00:14:47,820 --> 00:14:49,660 She's immediately accepted 139 00:14:49,660 --> 00:14:52,300 by these notoriously shy creatures. 140 00:14:55,300 --> 00:14:57,780 It's a privileged insider's view 141 00:14:57,780 --> 00:15:00,220 of the most sociable otter of all. 142 00:15:04,500 --> 00:15:06,780 Here, they not only have company - 143 00:15:06,780 --> 00:15:09,300 there are more eyes to spot danger. 144 00:15:11,540 --> 00:15:12,620 The spring melt 145 00:15:12,620 --> 00:15:14,660 makes the glaciers unstable. 146 00:15:41,460 --> 00:15:43,900 The icefall creates a rolling wave 147 00:15:43,900 --> 00:15:45,500 up to ten metres high. 148 00:15:48,380 --> 00:15:49,980 It may still be a danger 149 00:15:49,980 --> 00:15:51,700 over a kilometre away. 150 00:15:55,500 --> 00:15:56,700 In the turmoil, 151 00:15:56,700 --> 00:15:59,500 mothers and pups are easily separated. 152 00:16:02,900 --> 00:16:05,260 They must find refuge away from the glacier. 153 00:16:26,780 --> 00:16:28,380 In a cove, they find a solution 154 00:16:28,380 --> 00:16:30,140 to the turbulent waters. 155 00:16:32,860 --> 00:16:35,460 Kelp offers the moorings they need. 156 00:16:37,700 --> 00:16:39,140 It's just a matter 157 00:16:39,140 --> 00:16:40,780 of how best to attach themselves. 158 00:16:49,180 --> 00:16:52,060 But even this beginner is having success. 159 00:16:59,140 --> 00:17:00,700 As the ice vanishes, 160 00:17:00,700 --> 00:17:02,500 more kelp beds will soon appear. 161 00:17:03,780 --> 00:17:05,220 The otters can enjoy 162 00:17:05,220 --> 00:17:07,500 the upcoming summer in peace. 163 00:17:17,380 --> 00:17:19,980 Spring has also reached Manitoba 164 00:17:19,980 --> 00:17:21,060 in central Canada. 165 00:17:23,420 --> 00:17:24,820 It marks the beginning 166 00:17:24,820 --> 00:17:26,460 of an extraordinary awakening. 167 00:17:31,260 --> 00:17:33,140 These are garter snakes. 168 00:17:40,260 --> 00:17:42,700 After hibernating together underground, 169 00:17:42,700 --> 00:17:44,780 they emerge in their thousands. 170 00:17:49,580 --> 00:17:52,260 Remarkably, all are male. 171 00:17:56,780 --> 00:17:58,980 They warm themselves in the sun, 172 00:17:58,980 --> 00:18:00,860 preparing for the moment 173 00:18:00,860 --> 00:18:02,940 when the females emerge. 174 00:18:06,500 --> 00:18:08,300 This one has a camera. 175 00:18:12,300 --> 00:18:16,260 Our spy is entering a world governed by smell. 176 00:18:16,260 --> 00:18:19,700 Snakes use their tongues to pick up scent. 177 00:18:19,700 --> 00:18:21,820 All are searching for females. 178 00:18:27,020 --> 00:18:29,660 When the males detect a likely partner, 179 00:18:29,660 --> 00:18:31,260 they swarm all over her, 180 00:18:31,260 --> 00:18:33,700 desperate to be the first to mate. 181 00:18:36,540 --> 00:18:38,620 But Spy Snake is witnessing 182 00:18:38,620 --> 00:18:41,300 something quite extraordinary. 183 00:18:41,300 --> 00:18:43,460 Although there are no females here, 184 00:18:43,460 --> 00:18:45,060 the males are still swarming. 185 00:18:52,540 --> 00:18:54,620 And even more are joining the scrum. 186 00:19:03,980 --> 00:19:05,460 Nearby, others have also 187 00:19:05,460 --> 00:19:06,620 picked up the scent. 188 00:19:10,300 --> 00:19:12,500 Soon, there's no stopping them. 189 00:19:32,180 --> 00:19:34,060 As everyone piles in, Spy Snake 190 00:19:34,060 --> 00:19:37,060 becomes buried in the growing ball of snakes. 191 00:19:55,380 --> 00:19:57,380 Then, in the middle, 192 00:19:57,380 --> 00:19:59,580 the reason for the knot of serpents. 193 00:20:05,500 --> 00:20:06,780 An impostor - 194 00:20:06,780 --> 00:20:09,980 a male that smells like a female. 195 00:20:09,980 --> 00:20:13,340 He's deliberately attracting the males. 196 00:20:17,460 --> 00:20:20,940 His aim is to share their warmth. 197 00:20:20,940 --> 00:20:23,340 By fooling them into embracing him, 198 00:20:23,340 --> 00:20:25,100 he becomes superheated - 199 00:20:25,100 --> 00:20:27,660 a huge gain for a cold-blooded reptile 200 00:20:27,660 --> 00:20:29,260 looking for a mate. 201 00:20:31,460 --> 00:20:34,180 Finally, there she is. 202 00:20:38,020 --> 00:20:39,300 Her perfume is far stronger 203 00:20:39,300 --> 00:20:40,620 than the impostor. 204 00:20:44,100 --> 00:20:45,940 Nothing beats the real thing. 205 00:20:49,220 --> 00:20:51,460 The warmest males are already hot on her trail. 206 00:20:54,060 --> 00:20:57,500 But the superheated impostor leads the charge. 207 00:21:11,220 --> 00:21:14,380 Here, snakes that impersonate females 208 00:21:14,380 --> 00:21:15,980 get ahead in the mating game. 209 00:21:19,700 --> 00:21:21,460 Best leave them to it. 210 00:21:28,780 --> 00:21:30,180 Summer has arrived 211 00:21:30,180 --> 00:21:31,980 in the forests of southern Germany. 212 00:21:37,180 --> 00:21:38,700 The season of plenty 213 00:21:38,700 --> 00:21:41,780 for a secretive and industrious creature. 214 00:21:46,100 --> 00:21:48,300 The only clue to its presence - 215 00:21:48,300 --> 00:21:50,340 a carefully constructed woodpile. 216 00:21:55,140 --> 00:21:56,220 This is the time 217 00:21:56,220 --> 00:21:57,860 beavers raise their young. 218 00:21:59,420 --> 00:22:02,300 Making the most of the lush vegetation that summer brings. 219 00:22:04,140 --> 00:22:06,980 They recognise each other by smell. 220 00:22:06,980 --> 00:22:09,820 Rubbing noses confirms their friendship. 221 00:22:14,100 --> 00:22:15,340 They pair for life 222 00:22:15,340 --> 00:22:17,500 and live together as a family. 223 00:22:24,260 --> 00:22:26,300 They are wary of strangers. 224 00:22:28,060 --> 00:22:30,540 Newcomers enter at their own risk. 225 00:22:31,820 --> 00:22:34,420 Somehow, Spy Beaver must win them over. 226 00:22:36,260 --> 00:22:39,020 But first, he must pass the odour test. 227 00:22:43,420 --> 00:22:45,580 Real beavers have scent glands 228 00:22:45,580 --> 00:22:47,500 that tell family from foe. 229 00:22:50,100 --> 00:22:52,500 As our spy doesn't smell like a beaver, 230 00:22:52,500 --> 00:22:54,140 he's free to explore. 231 00:22:57,940 --> 00:23:00,540 Their lodge has a concealed entrance... 232 00:23:02,060 --> 00:23:04,260 ..that lets them come and go 233 00:23:04,260 --> 00:23:05,860 without being seen. 234 00:23:08,940 --> 00:23:11,180 Keeping a low profile hides them 235 00:23:11,180 --> 00:23:13,140 from predators like lynx and foxes. 236 00:23:18,380 --> 00:23:19,940 On the bank, a new spy 237 00:23:19,940 --> 00:23:21,580 is there to greet her. 238 00:23:25,620 --> 00:23:28,060 Beavers are strict vegetarians 239 00:23:28,060 --> 00:23:29,620 and Spy Baby Beaver 240 00:23:29,620 --> 00:23:31,700 is surrounded by willow - 241 00:23:31,700 --> 00:23:33,100 their favourite meal. 242 00:23:46,100 --> 00:23:48,180 Her teeth are coloured orange 243 00:23:48,180 --> 00:23:50,180 by iron deposits that strengthen them. 244 00:23:58,300 --> 00:24:00,340 They are also self-sharpening 245 00:24:00,340 --> 00:24:02,380 and slice through wood like a knife. 246 00:24:10,140 --> 00:24:14,140 Beavers can fell 300 shrubs and trees each year, 247 00:24:14,140 --> 00:24:16,380 clearing old growth and helping 248 00:24:16,380 --> 00:24:18,260 to maintain their entire ecosystem. 249 00:24:22,260 --> 00:24:23,740 For now, the youngsters 250 00:24:23,740 --> 00:24:25,300 leave it all to the grown-ups. 251 00:24:28,220 --> 00:24:29,980 They spend most of their time at play. 252 00:24:32,620 --> 00:24:35,260 Wrestling is a rarely filmed pastime. 253 00:24:57,140 --> 00:24:59,020 Beavers also have friends. 254 00:25:04,700 --> 00:25:05,740 A muskrat. 255 00:25:12,340 --> 00:25:14,700 This mini-me lives alongside the beavers, 256 00:25:14,700 --> 00:25:16,700 and even shares their lodge. 257 00:25:24,020 --> 00:25:26,060 Wherever the beaver goes, 258 00:25:26,060 --> 00:25:27,580 the muskrat follows. 259 00:25:32,660 --> 00:25:34,060 Being ten times smaller 260 00:25:34,060 --> 00:25:35,380 means the best food 261 00:25:35,380 --> 00:25:36,620 is usually out of reach. 262 00:25:37,900 --> 00:25:40,260 But while the beaver does the hard work, 263 00:25:40,260 --> 00:25:42,100 the muskrat can sit back. 264 00:25:58,140 --> 00:26:00,340 This is what friends are for. 265 00:26:11,180 --> 00:26:12,580 Beavers with young 266 00:26:12,580 --> 00:26:14,420 are always on high alert. 267 00:26:37,180 --> 00:26:38,220 A false alarm. 268 00:26:41,220 --> 00:26:42,420 But always best to err 269 00:26:42,420 --> 00:26:43,700 on the side of caution. 270 00:26:49,820 --> 00:26:51,180 After a fright, 271 00:26:51,180 --> 00:26:52,780 grooming is a comfort for everyone. 272 00:27:00,060 --> 00:27:01,940 By creating a layer of air 273 00:27:01,940 --> 00:27:03,940 between skin and underfur, 274 00:27:03,940 --> 00:27:05,780 it provides insulation. 275 00:27:11,020 --> 00:27:12,860 Harmony is soon restored. 276 00:27:15,820 --> 00:27:16,940 While the muskrat 277 00:27:16,940 --> 00:27:18,300 just keeps himself busy. 278 00:27:25,340 --> 00:27:27,980 For Mum, a well-earned massage 279 00:27:27,980 --> 00:27:30,020 after a hard day's work. 280 00:27:40,220 --> 00:27:41,900 As early summer arrives, 281 00:27:41,900 --> 00:27:44,500 Baha, California becomes the focus 282 00:27:44,500 --> 00:27:46,420 of a great natural gathering. 283 00:27:48,100 --> 00:27:50,100 Here, brown pelicans patrol 284 00:27:50,100 --> 00:27:53,060 some of the richest fishing grounds in the world. 285 00:28:01,460 --> 00:28:03,900 There's a new member of the flock. 286 00:28:03,900 --> 00:28:05,500 A spy on the wing. 287 00:28:08,940 --> 00:28:11,420 One that can film the fishing party 288 00:28:11,420 --> 00:28:12,940 wing tip to wing tip. 289 00:28:27,020 --> 00:28:28,460 Clear, warm currents 290 00:28:28,460 --> 00:28:30,300 create plankton blooms. 291 00:28:30,300 --> 00:28:32,100 Huge fish shoals are found. 292 00:28:36,660 --> 00:28:37,820 It's just a matter 293 00:28:37,820 --> 00:28:39,220 of spotting them from the air. 294 00:28:42,540 --> 00:28:44,700 Then taking them by surprise. 295 00:28:57,340 --> 00:28:59,380 But where fishing is easy, 296 00:28:59,380 --> 00:29:01,980 everyone wants a piece of the action. 297 00:29:03,820 --> 00:29:05,020 Bottlenose dolphins. 298 00:29:09,820 --> 00:29:12,140 By spreading out, they increase 299 00:29:12,140 --> 00:29:13,740 their chances of finding a shoal. 300 00:29:16,620 --> 00:29:18,620 Dolphins are intensely curious. 301 00:29:21,900 --> 00:29:23,500 They leap to check out 302 00:29:23,500 --> 00:29:25,540 the strange bird that's following them. 303 00:29:46,060 --> 00:29:47,500 Here, it's not just dolphins 304 00:29:47,500 --> 00:29:48,900 that take to the air. 305 00:29:52,980 --> 00:29:54,820 Mobula rays. 306 00:30:07,420 --> 00:30:09,260 Why they leap is a mystery. 307 00:30:14,460 --> 00:30:17,380 But it might be a signal to show where food has been found. 308 00:30:36,660 --> 00:30:41,780 For where rays are jumping, huge blooms of plankton are not far away. 309 00:30:46,460 --> 00:30:50,460 And rays converge in their tens of thousands to feed. 310 00:31:14,020 --> 00:31:16,580 The aerial view may be astonishing, 311 00:31:16,580 --> 00:31:18,500 but more wonder lies below. 312 00:31:24,380 --> 00:31:28,020 Spy Ray gets closer than any human diver can. 313 00:31:31,700 --> 00:31:33,500 Deep into the heart of the shoal. 314 00:31:50,740 --> 00:31:53,900 With a spy swimming among them 315 00:31:53,900 --> 00:31:56,100 and a spy in the sky, 316 00:31:56,100 --> 00:31:59,900 our cameras capture an event never filmed before. 317 00:32:03,900 --> 00:32:06,620 As the rays circle, they create a vortex, 318 00:32:06,620 --> 00:32:08,980 concentrating the plankton inside. 319 00:32:17,820 --> 00:32:21,060 At every turn, more plankton is sucked into the centre. 320 00:32:22,260 --> 00:32:24,900 They just have to scoop it up. 321 00:32:32,860 --> 00:32:35,060 When they feed near the surface, 322 00:32:35,060 --> 00:32:37,140 they use a different technique. 323 00:32:37,140 --> 00:32:39,300 Ripples pass through the masses, 324 00:32:39,300 --> 00:32:41,540 like a subaquatic Mexican wave. 325 00:32:55,220 --> 00:32:57,380 Soon, the leaping starts again. 326 00:33:01,500 --> 00:33:06,340 For Spy Ray, it's a case of, if you can't beat them, join them. 327 00:33:23,020 --> 00:33:27,300 As the day ends, our spy keeps leaping with the best of them. 328 00:33:36,500 --> 00:33:38,220 GULLS CRY 329 00:33:40,260 --> 00:33:42,100 It's midsummer in Alaska. 330 00:33:43,540 --> 00:33:46,020 The fishing season for grizzly bears. 331 00:33:48,180 --> 00:33:50,020 THEY GROWL PLAYFULLY 332 00:33:52,100 --> 00:33:53,900 With uncanny timing, 333 00:33:53,900 --> 00:33:57,980 mother bears bring their cubs to a remarkable event. 334 00:33:59,780 --> 00:34:03,820 Soon, a million salmon will pass up this river to spawn. 335 00:34:03,820 --> 00:34:06,740 BEAR HUFFS 336 00:34:06,740 --> 00:34:09,500 This year, a newcomer is joining them. 337 00:34:16,100 --> 00:34:20,460 With his teddy-bear looks and camera eye, he's well prepared. 338 00:34:24,140 --> 00:34:26,460 Late arrivals must be quick. 339 00:34:26,460 --> 00:34:29,020 The best fishing spots will soon be taken. 340 00:34:30,580 --> 00:34:33,260 BEAR GRUNTS 341 00:34:33,260 --> 00:34:35,700 Our spy also has a quick way down. 342 00:34:42,820 --> 00:34:44,940 He's now in prime position. 343 00:34:49,380 --> 00:34:53,380 Risky, when a mother bear is still staking out her claim. 344 00:34:56,380 --> 00:34:58,420 SHE SNORTS 345 00:35:04,140 --> 00:35:05,980 SHE SNIFFS 346 00:35:08,940 --> 00:35:11,340 But he seems to have got away with it. 347 00:35:23,460 --> 00:35:25,340 For all, it's a waiting game. 348 00:35:27,460 --> 00:35:29,580 The tide is out, and the river empty. 349 00:35:32,860 --> 00:35:36,060 But her cubs have yet to master the art of patience. 350 00:35:38,100 --> 00:35:41,060 They head out to the estuary to search for the salmon. 351 00:35:45,980 --> 00:35:48,420 Leaving mother bear to bide her time. 352 00:35:54,780 --> 00:35:58,100 Spy Bald Eagle is already on their trail. 353 00:36:00,060 --> 00:36:03,060 Bears can smell fish up to 20 miles away. 354 00:36:07,940 --> 00:36:11,380 By following their nose, they soon find where the salmon are gathering. 355 00:36:21,340 --> 00:36:23,100 With fish everywhere, 356 00:36:23,100 --> 00:36:25,820 just how hard can it be to catch one? 357 00:37:07,860 --> 00:37:10,700 Finally, after all that effort. 358 00:37:18,020 --> 00:37:20,620 Older bears know better than to waste their energy. 359 00:37:21,940 --> 00:37:24,460 They've learnt that salmon arrive on the high tide. 360 00:37:27,020 --> 00:37:29,580 But the first is not what it seems. 361 00:37:31,780 --> 00:37:34,700 Spy Salmon swims just like the real thing. 362 00:37:43,060 --> 00:37:46,780 It, too, is ready to run the gauntlet of the bears. 363 00:37:49,940 --> 00:37:52,780 In its wake are countless sockeye salmon. 364 00:37:58,260 --> 00:38:00,500 They've travelled thousands of miles 365 00:38:00,500 --> 00:38:04,100 to spawn in the river where once they were born. 366 00:38:14,340 --> 00:38:17,380 The salmon bottleneck beneath the falls, 367 00:38:17,380 --> 00:38:19,860 before taking a leap into the unknown. 368 00:38:22,180 --> 00:38:24,260 A prime spot for fishing. 369 00:38:29,940 --> 00:38:32,580 Bears can see underwater. 370 00:38:32,580 --> 00:38:34,580 Useful for targeting. 371 00:38:53,140 --> 00:38:56,100 With so many fish, it's like bobbing for apples. 372 00:39:06,900 --> 00:39:09,580 They can eat over 30 salmon a day, 373 00:39:09,580 --> 00:39:12,180 and almost double their weight in the fishing season. 374 00:39:15,700 --> 00:39:18,860 They soon become fussy, picking the most nutritious treats, 375 00:39:18,860 --> 00:39:20,900 like the skin and head. 376 00:39:24,700 --> 00:39:27,860 But any good party can attract unwelcome guests. 377 00:39:33,700 --> 00:39:35,540 THEY GRUNT 378 00:39:39,020 --> 00:39:41,420 They have good reason to feel nervous. 379 00:39:43,020 --> 00:39:45,140 Males can kill cubs. 380 00:39:53,180 --> 00:39:55,020 One mother makes a stand. 381 00:39:56,260 --> 00:39:58,100 SHE GROWLS FEROCIOUSLY 382 00:40:00,580 --> 00:40:02,220 She's joined by another. 383 00:40:04,780 --> 00:40:06,620 THEY GROWL 384 00:40:17,420 --> 00:40:22,060 He may be powerful, but he's no match for a mother's fury. 385 00:40:45,220 --> 00:40:47,140 He won't be back in a hurry. 386 00:40:51,340 --> 00:40:53,620 Now that the cubs have nothing to fear, 387 00:40:53,620 --> 00:40:55,700 why not tackle a bear of their own? 388 00:41:02,420 --> 00:41:04,220 Grab the paw first... 389 00:41:11,180 --> 00:41:12,900 That showed him. 390 00:41:14,860 --> 00:41:16,540 Now the killer bite. 391 00:41:21,780 --> 00:41:23,860 Maybe not. 392 00:41:25,220 --> 00:41:27,460 SPY BEAR GRUNTS 393 00:41:28,700 --> 00:41:31,740 Meanwhile, Spy Salmon has been left high and dry. 394 00:41:33,940 --> 00:41:35,860 Surely a better bet. 395 00:41:48,340 --> 00:41:51,420 Never mind, there's always one that gets away. 396 00:42:01,020 --> 00:42:04,260 As summer draws to an end, Istanbul and Turkey 397 00:42:04,260 --> 00:42:07,260 sets the scene for another great spectacle. 398 00:42:09,340 --> 00:42:13,180 White storks are heading south to escape Europe's upcoming winter, 399 00:42:13,180 --> 00:42:14,980 when food will be hard to find. 400 00:42:16,780 --> 00:42:20,060 Half a million will make the perilous journey to Africa 401 00:42:20,060 --> 00:42:22,300 of up to 8,000 miles. 402 00:42:28,380 --> 00:42:29,860 They have a fellow traveller. 403 00:42:33,340 --> 00:42:36,540 He joins them in the thermals that rise from the ground below. 404 00:42:41,100 --> 00:42:45,580 Spy Stork's broad wings are designed to ride these natural elevators, 405 00:42:45,580 --> 00:42:47,900 just like the real birds. 406 00:42:47,900 --> 00:42:49,940 WIND GUSTS 407 00:42:49,940 --> 00:42:52,380 The twisting columns of hot air 408 00:42:52,380 --> 00:42:54,780 offer the storks a free ride upwards. 409 00:43:05,500 --> 00:43:07,300 WIND GUSTS 410 00:43:17,580 --> 00:43:19,780 Once they reach the top of one thermal, 411 00:43:19,780 --> 00:43:22,020 they simply glide to another. 412 00:43:25,940 --> 00:43:28,940 They head to the city with hardly a wing flap. 413 00:43:30,220 --> 00:43:32,700 Good move. 414 00:43:32,700 --> 00:43:35,860 The roads and buildings of Istanbul reflect the heat, 415 00:43:35,860 --> 00:43:37,460 creating huge thermals 416 00:43:37,460 --> 00:43:38,860 which carry them upwards 417 00:43:38,860 --> 00:43:40,500 even higher than before. 418 00:44:02,700 --> 00:44:06,980 Riding only on hot air, they can reach heights of nearly a mile. 419 00:44:12,860 --> 00:44:15,060 They need the altitude. 420 00:44:15,060 --> 00:44:18,020 They now face the riskiest part of their journey. 421 00:44:18,020 --> 00:44:21,260 Because thermals don't form over water. 422 00:44:35,860 --> 00:44:37,620 As they try to glide, 423 00:44:37,620 --> 00:44:39,900 there's nothing to give them the lift they need. 424 00:44:45,180 --> 00:44:47,820 Those who hadn't gained enough height on land 425 00:44:47,820 --> 00:44:49,180 soon drop from the sky. 426 00:44:57,220 --> 00:44:59,140 To avoid plunging into the sea, 427 00:44:59,140 --> 00:45:01,340 they must flap their heavy wings. 428 00:45:05,500 --> 00:45:07,060 They start burning body fat 429 00:45:07,060 --> 00:45:08,540 just to stay airborne. 430 00:45:08,540 --> 00:45:10,300 Consuming 20 times more energy 431 00:45:10,300 --> 00:45:11,580 than when they glide. 432 00:45:16,220 --> 00:45:20,020 If a wing so much as touches the water, they will fall in and drown. 433 00:45:24,820 --> 00:45:26,660 They are battling for their lives. 434 00:45:37,300 --> 00:45:39,740 Then, suddenly, a lifeline. 435 00:45:41,940 --> 00:45:44,100 An outcrop rising from the sea. 436 00:45:56,380 --> 00:45:58,140 Just enough sun-baked rock 437 00:45:58,140 --> 00:46:01,260 to create the thermals they so desperately need. 438 00:46:12,180 --> 00:46:15,580 It's a free ride upwards that saves their lives. 439 00:46:20,220 --> 00:46:23,300 In this way, storks use islands as stepping stones 440 00:46:23,300 --> 00:46:25,060 to help survive the crossing. 441 00:46:27,060 --> 00:46:28,940 Travelling only by day, 442 00:46:28,940 --> 00:46:32,140 it can take four weeks before they arrive over the plains of Africa. 443 00:46:37,660 --> 00:46:39,380 BIRDSONG 444 00:46:46,980 --> 00:46:50,580 Here, they'll have all the insects and other food they need 445 00:46:50,580 --> 00:46:53,660 as they wait out Europe's upcoming winter. 446 00:46:53,660 --> 00:46:55,580 BIRDSONG 447 00:47:05,300 --> 00:47:08,260 In England, the early-morning mist 448 00:47:08,260 --> 00:47:11,140 signals that autumn has finally arrived. 449 00:47:13,220 --> 00:47:17,860 And with it, the greatest and most colourful transformation in nature. 450 00:47:33,900 --> 00:47:35,780 The trees survive the winter 451 00:47:35,780 --> 00:47:39,460 by taking back nutrients and chlorophyll from the leaves. 452 00:47:48,100 --> 00:47:50,980 What's left behind are the autumn hues. 453 00:47:53,900 --> 00:47:56,620 The leaves that once fed the trees are then discarded. 454 00:48:01,180 --> 00:48:03,980 Grey squirrels are among the many preparing themselves 455 00:48:03,980 --> 00:48:05,820 for the changing season. 456 00:48:08,780 --> 00:48:10,500 CROWS CAW 457 00:48:15,380 --> 00:48:19,180 Spy Squirrel is poised and ready with his camera eye. 458 00:48:24,900 --> 00:48:26,300 Well, nearly ready. 459 00:48:28,820 --> 00:48:31,100 Along with his spy nut, 460 00:48:31,100 --> 00:48:33,100 other disguised cameras are strewn 461 00:48:33,100 --> 00:48:34,500 across the forest floor. 462 00:48:43,100 --> 00:48:46,500 In autumn, squirrels stock up their winter larder. 463 00:48:49,180 --> 00:48:52,060 Each may bury around 10,000 nuts. 464 00:48:52,060 --> 00:48:54,420 In an amazing feat of memory, 465 00:48:54,420 --> 00:48:56,700 they may retrieve 4,000 of them. 466 00:48:58,420 --> 00:49:01,980 With so many nuts to find, competition is rife. 467 00:49:01,980 --> 00:49:04,100 HIGH-PITCHED SHRIEKING 468 00:49:17,220 --> 00:49:19,940 Every nut is a gift for would-be thieves. 469 00:49:20,780 --> 00:49:23,100 CROWS CAW 470 00:49:28,100 --> 00:49:31,540 In fact, around a fifth of all squirrels steal from others. 471 00:49:33,940 --> 00:49:36,180 That'll do nicely. 472 00:49:50,780 --> 00:49:53,820 It's one thing to steal a nut - 473 00:49:53,820 --> 00:49:56,660 another to keep hold of it. 474 00:50:01,220 --> 00:50:04,020 It's not just squirrels feeling the seasonal change. 475 00:50:05,460 --> 00:50:07,460 Autumn is the rutting season for red deer. 476 00:50:09,580 --> 00:50:13,140 By breeding now, they will have their young in the summer. 477 00:50:16,700 --> 00:50:18,420 Their stag. 478 00:50:18,420 --> 00:50:20,220 He tries to gather together 479 00:50:20,220 --> 00:50:21,700 as many hinds as he can. 480 00:50:23,700 --> 00:50:25,980 Perhaps 20 in all. 481 00:50:28,900 --> 00:50:31,820 Spy Squirrel is right in the middle of his herd. 482 00:50:36,300 --> 00:50:38,700 But the stag has other things on his mind. 483 00:50:41,300 --> 00:50:43,220 STAG BELLOWS 484 00:50:43,220 --> 00:50:46,580 In the rutting season, he has his work cut out. 485 00:50:49,100 --> 00:50:51,340 Rounding up his straying hinds 486 00:50:51,340 --> 00:50:52,980 is a constant battle. 487 00:51:07,980 --> 00:51:12,260 But he has an even bigger challenge - a rival. 488 00:51:13,900 --> 00:51:15,620 STAG BELLOWS 489 00:51:17,820 --> 00:51:21,220 A bevy of hinds is just what he's looking for. 490 00:51:27,740 --> 00:51:30,180 Females will go with the strongest stag. 491 00:51:30,180 --> 00:51:32,580 STAG BELLOWS 492 00:51:34,860 --> 00:51:38,260 The rival must fight to prove his mettle. 493 00:51:38,260 --> 00:51:39,700 STAGS BELLOW 494 00:51:48,020 --> 00:51:50,100 Battle lines are drawn. 495 00:51:58,460 --> 00:52:00,940 One mistake could prove fatal. 496 00:52:03,260 --> 00:52:05,340 Whoever gains most ground wins. 497 00:52:08,940 --> 00:52:11,180 Victory for the reigning stag. 498 00:52:11,180 --> 00:52:12,780 STAG BELLOWS 499 00:52:12,780 --> 00:52:15,220 Spy Squirrel may be worse for wear, 500 00:52:15,220 --> 00:52:18,700 but he still captures one final shot of the champion. 501 00:52:18,700 --> 00:52:20,300 STAG BELLOWS 502 00:52:26,700 --> 00:52:29,340 For the squirrels, there's still one last nut 503 00:52:29,340 --> 00:52:31,860 they've yet to get their paws on. 504 00:52:41,700 --> 00:52:44,740 Another trophy to squirrel away. 505 00:52:57,020 --> 00:52:59,180 Back in Germany, among the beavers, 506 00:52:59,180 --> 00:53:01,420 autumn is also well underway. 507 00:53:02,900 --> 00:53:05,380 It won't be long until the winter sets in. 508 00:53:10,980 --> 00:53:14,220 Before then, their lodge must undergo some maintenance. 509 00:53:16,580 --> 00:53:18,820 Spy Beaver investigates. 510 00:53:22,100 --> 00:53:24,380 It's the beavers' busiest time of year. 511 00:53:26,620 --> 00:53:29,340 They scour the river for building material. 512 00:53:34,940 --> 00:53:38,300 Stones help stabilise the lodge against flooding. 513 00:53:44,060 --> 00:53:47,700 Preparing their home for winter is everyone's responsibility. 514 00:53:57,900 --> 00:54:00,660 Sticks and logs bring strength to the structure. 515 00:54:08,820 --> 00:54:11,220 It can also be used to plug holes 516 00:54:11,220 --> 00:54:13,260 and reduce leaks to the main chamber. 517 00:54:20,860 --> 00:54:23,420 Small sticks are used to fill in the gaps. 518 00:54:25,340 --> 00:54:29,100 To cap it all, a thatch of turf helps weatherproof the roof. 519 00:54:33,180 --> 00:54:36,180 On the river bank, the whole family is hard at work 520 00:54:36,180 --> 00:54:38,420 collecting food and nesting material. 521 00:54:44,340 --> 00:54:46,300 Even the youngsters do their bit. 522 00:54:53,020 --> 00:54:56,260 The beavers must harvest what they can before winter sets in. 523 00:54:58,980 --> 00:55:01,380 Everything must be ferried back home. 524 00:55:04,780 --> 00:55:07,540 The muskrat uses grass as nesting material 525 00:55:07,540 --> 00:55:09,940 to furnish his own quarters in the lodge. 526 00:55:19,900 --> 00:55:23,940 As winter approaches, the beavers redouble their efforts. 527 00:55:37,300 --> 00:55:39,980 And the muskrat gets ever more ambitious. 528 00:55:52,780 --> 00:55:55,060 With everyone working flat-out, 529 00:55:55,060 --> 00:55:57,860 they'll soon be ready for the upcoming winter. 530 00:56:05,020 --> 00:56:07,900 They'll spend most of it safely tucked up inside. 531 00:56:15,780 --> 00:56:17,580 As the year comes to an end, 532 00:56:17,580 --> 00:56:19,780 the snows have returned to Japan. 533 00:56:22,940 --> 00:56:25,980 Already, the macaques are huddling together for warmth. 534 00:56:31,580 --> 00:56:33,420 Once more, their social life 535 00:56:33,420 --> 00:56:35,260 revolves around the hot tub. 536 00:56:41,460 --> 00:56:43,980 Our spies are at the end of their mission. 537 00:56:49,980 --> 00:56:52,580 Sweet dreams soon come to all. 538 00:57:07,420 --> 00:57:09,980 Time-out for our spy creatures, too. 539 00:57:16,940 --> 00:57:21,180 Next time - our spies travel to the islands of the southern seas 540 00:57:21,180 --> 00:57:24,620 to meet yet more extraordinary animals.