1 00:00:09,200 --> 00:00:11,080 From the mighty grizzly bear... 2 00:00:14,960 --> 00:00:19,000 ..to the endearing, real-life Paddington, the spectacled bear... 3 00:00:22,280 --> 00:00:26,320 ..and the majestic polar bear, king of the frozen North... 4 00:00:31,840 --> 00:00:36,840 ..this remarkable animal family has long captured our imagination. 5 00:00:38,800 --> 00:00:42,560 But as some of the biggest animals on Earth, they need 6 00:00:42,560 --> 00:00:45,880 more than just the bare necessities to get by. 7 00:00:48,280 --> 00:00:52,520 So, whether it's raiding nature's larder, 8 00:00:52,520 --> 00:00:54,560 standing up to their rivals... 9 00:00:59,640 --> 00:01:01,000 ..raising the cubs... 10 00:01:04,280 --> 00:01:07,440 ..or even proving that you're smarter than the average bear... 11 00:01:09,800 --> 00:01:13,240 ..each must draw on all its skills to survive. 12 00:01:15,760 --> 00:01:19,800 Today, bears face their biggest obstacles yet... 13 00:01:22,000 --> 00:01:25,400 ..as they try to get to grips with a changing world. 14 00:01:28,080 --> 00:01:31,760 But whatever they're confronted with, 15 00:01:31,760 --> 00:01:36,360 bears always try and take life in their stride. 16 00:01:49,320 --> 00:01:52,240 Bears are some of the most charismatic animals 17 00:01:52,240 --> 00:01:53,560 to walk our planet... 18 00:01:55,720 --> 00:01:58,840 ..and they all share the same key characteristics. 19 00:02:01,160 --> 00:02:04,720 Like this brown bear, their impressive size 20 00:02:04,720 --> 00:02:06,880 and strength sets them apart. 21 00:02:08,720 --> 00:02:12,280 They have forward-facing eyes with vision similar to our own. 22 00:02:15,440 --> 00:02:19,640 But their sense of smell is over 100 times more powerful. 23 00:02:24,280 --> 00:02:27,600 Large, dexterous paws are tipped with long claws 24 00:02:27,600 --> 00:02:30,480 that can open up even more opportunities. 25 00:02:35,960 --> 00:02:39,400 Although they're classed as carnivores, most bears eat 26 00:02:39,400 --> 00:02:42,760 a diverse mix of plants, insects and meat. 27 00:02:46,360 --> 00:02:50,760 Across the world, there are just eight species, 28 00:02:50,760 --> 00:02:53,800 yet they range over a wide variety of habitats... 29 00:02:56,200 --> 00:02:59,160 ..from the ice world of the North, 30 00:02:59,160 --> 00:03:02,200 through the mountains of Asia... 31 00:03:04,760 --> 00:03:06,760 ..to the heat of the tropics. 32 00:03:12,640 --> 00:03:16,160 To live in these very different places, they've had to adapt. 33 00:03:19,600 --> 00:03:23,240 The skills they need to survive must be learned and mastered 34 00:03:23,240 --> 00:03:24,440 over a lifetime. 35 00:03:25,480 --> 00:03:28,880 So making it as a bear is far from easy. 36 00:03:34,640 --> 00:03:37,080 Katmai National Park in Alaska - 37 00:03:37,080 --> 00:03:39,400 a wilderness where mountains 38 00:03:39,400 --> 00:03:40,760 meet the sea. 39 00:03:46,400 --> 00:03:48,400 This is home to the brown bear, 40 00:03:48,400 --> 00:03:50,400 sometimes known as the grizzly. 41 00:03:53,320 --> 00:03:55,160 GROWLS 42 00:03:55,160 --> 00:03:57,720 And they're gathering for one of the most extraordinary 43 00:03:57,720 --> 00:03:59,200 events in nature... 44 00:04:05,080 --> 00:04:06,280 ..the salmon run. 45 00:04:11,600 --> 00:04:15,960 Every summer, millions of salmon head upstream to spawn. 46 00:04:24,240 --> 00:04:27,640 Waterfalls are a natural barrier for the migrating fish... 47 00:04:30,240 --> 00:04:31,920 ..and the bears know it. 48 00:04:51,960 --> 00:04:54,360 Three cubs emerge from the forest. 49 00:04:56,480 --> 00:04:59,120 Their mother is thin and needs to eat. 50 00:05:00,160 --> 00:05:03,000 But this is a dangerous place for a young family. 51 00:05:10,680 --> 00:05:11,720 THEY GROWL 52 00:05:11,720 --> 00:05:14,320 Competition for every fish is fierce. 53 00:05:20,440 --> 00:05:23,720 For their own safety, the cubs are kept on the sidelines. 54 00:05:28,360 --> 00:05:31,200 It's a prime position to watch the action. 55 00:05:34,080 --> 00:05:37,520 Catching a powerful, slippery salmon is tough... 56 00:05:40,160 --> 00:05:44,160 ..and the grizzlies, like all bears, must work out the best way to tackle 57 00:05:44,160 --> 00:05:45,400 the food on offer. 58 00:05:47,200 --> 00:05:49,080 There's the dash and grab. 59 00:05:54,600 --> 00:05:57,600 Less energetic is the stand and wait approach. 60 00:06:01,080 --> 00:06:02,880 But it has its downsides. 61 00:06:09,440 --> 00:06:14,680 Beneath the falls, sit and wait is the most successful strategy. 62 00:06:18,280 --> 00:06:20,480 Fights can break out at any moment. 63 00:06:25,280 --> 00:06:28,280 For now, the cubs are out of their depth. 64 00:06:33,800 --> 00:06:37,400 An experienced big male can catch 30 salmon a day... 65 00:06:40,240 --> 00:06:42,880 ..and eventually most of them have had enough. 66 00:06:53,480 --> 00:06:56,280 The mother bear decides it's safe to return. 67 00:07:10,560 --> 00:07:12,520 Her cubs are depending on her. 68 00:07:24,120 --> 00:07:25,960 A perfectly timed catch. 69 00:07:29,200 --> 00:07:31,680 Patience and experience pay off... 70 00:07:37,120 --> 00:07:39,000 ..and the family can feed. 71 00:07:47,720 --> 00:07:51,080 The skill and judgment needed to master a chaotic situation 72 00:07:51,080 --> 00:07:57,080 like this, with tricky prey and other bears, takes years to learn. 73 00:08:00,080 --> 00:08:03,360 So, for cubs, lessons start early. 74 00:08:07,480 --> 00:08:09,680 The forested areas of North America 75 00:08:09,680 --> 00:08:14,640 are home to the grizzlies' smaller cousin, the American black bear. 76 00:08:17,360 --> 00:08:20,880 These cubs are nearly four months old and, at this age, 77 00:08:20,880 --> 00:08:23,120 they're learning new skills every day. 78 00:08:29,360 --> 00:08:31,880 Play fighting improves their coordination 79 00:08:31,880 --> 00:08:33,440 and builds muscle strength. 80 00:08:38,520 --> 00:08:42,320 It also helps sort out who's who in the pecking order. 81 00:08:48,480 --> 00:08:51,920 The youngest cub soon learns her lowly position. 82 00:08:56,360 --> 00:08:59,440 She may be last in line, but she still benefits 83 00:08:59,440 --> 00:09:00,800 from her mother's milk. 84 00:09:03,960 --> 00:09:06,120 It's almost 25% fat. 85 00:09:07,760 --> 00:09:10,560 That's five times as rich as cow's milk. 86 00:09:10,560 --> 00:09:14,480 THEY GRUNT 87 00:09:17,320 --> 00:09:21,520 Soon, these cubs will move on to solids, so they're starting 88 00:09:21,520 --> 00:09:23,800 to investigate other food around them. 89 00:09:32,960 --> 00:09:37,160 In spring, young leaves and ants are a good source of protein. 90 00:09:38,840 --> 00:09:41,240 But it's too early for pine nuts. 91 00:09:52,280 --> 00:09:56,880 Learning what they can eat and when will be vital in the future. 92 00:10:05,240 --> 00:10:08,200 But right now, the cubs are vulnerable, 93 00:10:08,200 --> 00:10:10,520 and there are more pressing issues. 94 00:10:15,400 --> 00:10:18,000 There are predators in these forests. 95 00:10:21,680 --> 00:10:24,160 A bald eagle could snatch and kill a cub... 96 00:10:29,560 --> 00:10:30,800 ..as could a coyote. 97 00:10:33,360 --> 00:10:36,200 Most dangerous of all are grey wolves. 98 00:10:43,440 --> 00:10:46,240 But there is a place the cubs can seek safety. 99 00:10:58,480 --> 00:11:01,000 Thanks to their strong, curved claws... 100 00:11:02,720 --> 00:11:05,360 ..these bear cubs can climb from a young age. 101 00:11:08,200 --> 00:11:10,480 But perfecting the technique takes time. 102 00:11:13,160 --> 00:11:16,400 They need to work out which trees are best for gripping onto. 103 00:11:20,240 --> 00:11:24,240 Smaller trees and branches are good for practice - 104 00:11:24,240 --> 00:11:25,640 well, most of the time. 105 00:11:29,320 --> 00:11:31,160 This tree is too flaky. 106 00:11:36,240 --> 00:11:38,080 This tree is too slippy. 107 00:11:44,360 --> 00:11:46,920 But this tree is just right. 108 00:11:53,880 --> 00:11:55,520 Going up is one thing... 109 00:12:00,600 --> 00:12:04,160 ..but coming down again can require a helping hand. 110 00:12:05,560 --> 00:12:10,160 THEY GROWL 111 00:12:13,640 --> 00:12:16,240 All bears must learn how to avoid danger... 112 00:12:17,800 --> 00:12:21,920 ..and there's one species that's come up with an unusual strategy. 113 00:12:31,520 --> 00:12:32,880 India... 114 00:12:35,960 --> 00:12:37,760 ..home to the sloth bear. 115 00:12:40,440 --> 00:12:43,240 Here, there are fewer tall trees to escape into. 116 00:12:46,320 --> 00:12:49,920 And, in any case, the local predators are skilled climbers. 117 00:12:53,240 --> 00:12:57,080 So these sloth bear cubs need a different escape plan. 118 00:13:02,520 --> 00:13:05,480 WAILING 119 00:13:05,480 --> 00:13:09,280 When their mother sounds the alarm, 120 00:13:09,280 --> 00:13:11,280 they head for the safest place around. 121 00:13:14,400 --> 00:13:17,200 Her shaggy coat means the cubs can climb 122 00:13:17,200 --> 00:13:22,480 onto her back, clinging on using strong forelegs and toes. 123 00:13:27,760 --> 00:13:32,040 It's unusual for a big cat to challenge a sloth bear mother... 124 00:13:33,520 --> 00:13:36,360 ..unlike her cubs, who so often do. 125 00:13:42,960 --> 00:13:47,440 A mother bear is the cubs' protection and their only guide. 126 00:13:54,520 --> 00:13:57,000 With so many skills to learn, 127 00:13:57,000 --> 00:14:00,440 most bear cubs stay with their mother for two to three years. 128 00:14:00,440 --> 00:14:02,880 THEY GROWL 129 00:14:04,760 --> 00:14:08,040 In Alaska, a five-month-old grizzly bear cub 130 00:14:08,040 --> 00:14:10,000 is working out his boundaries. 131 00:14:14,800 --> 00:14:18,240 Adult bears spend most of their lives alone, 132 00:14:18,240 --> 00:14:22,360 so this time with his mother helps him learn how to interact 133 00:14:22,360 --> 00:14:23,640 with other bears. 134 00:14:27,520 --> 00:14:30,720 All cubs need to master their new surroundings. 135 00:14:32,520 --> 00:14:33,840 In the Arctic, 136 00:14:33,840 --> 00:14:37,040 young polar bears emerge from their den to take their first 137 00:14:37,040 --> 00:14:38,400 steps in the snow. 138 00:14:41,240 --> 00:14:43,200 This cub is more cautious. 139 00:14:47,800 --> 00:14:50,240 They need to get to grips with this terrain quickly. 140 00:14:53,320 --> 00:14:56,320 Soon, they will have to walk many miles in search of food. 141 00:15:02,200 --> 00:15:06,840 In Canada, another grizzly bear cub is trying his luck at fishing. 142 00:15:11,160 --> 00:15:12,960 His mother shows how it's done. 143 00:15:18,120 --> 00:15:21,640 Observational learning is one of the most effective ways for cubs 144 00:15:21,640 --> 00:15:26,400 to pick up new skills, and, with so many salmon here, 145 00:15:26,400 --> 00:15:27,960 he's got a good chance. 146 00:15:33,880 --> 00:15:36,120 Now to hold on to it. 147 00:15:47,480 --> 00:15:49,520 As cubs grow more independent... 148 00:15:51,320 --> 00:15:54,160 ..they start trying things out for themselves. 149 00:15:59,080 --> 00:16:03,120 In the woodlands of Minnesota, a fallen tree holds something 150 00:16:03,120 --> 00:16:05,360 that bears are famously fond of... 151 00:16:07,480 --> 00:16:09,000 ..honey. 152 00:16:09,000 --> 00:16:11,800 BEES BUZZ 153 00:16:11,800 --> 00:16:13,920 And it hasn't gone unnoticed. 154 00:16:20,800 --> 00:16:23,880 This nine-month-old black bear cub may have never 155 00:16:23,880 --> 00:16:25,680 encountered bees before... 156 00:16:30,440 --> 00:16:33,920 ..and sometimes learning can be a painful process. 157 00:16:41,760 --> 00:16:42,760 HE GROWLS 158 00:16:46,640 --> 00:16:50,200 His more experienced mother has a tried and tested technique. 159 00:16:53,240 --> 00:16:57,000 This smash and grab leads to fewer stings. 160 00:17:08,160 --> 00:17:10,840 Honeycomb provides sugars and protein 161 00:17:10,840 --> 00:17:12,760 from the bee larvae inside. 162 00:17:16,240 --> 00:17:21,320 Much of a cub's learning is focused on food. As one of the biggest land 163 00:17:21,320 --> 00:17:26,720 animals, some bears need over 5,000 calories just on an average day. 164 00:17:28,880 --> 00:17:30,520 In many parts of the world, 165 00:17:30,520 --> 00:17:35,440 bears have to adapt and specialise to fuel their sizable appetites. 166 00:17:38,440 --> 00:17:41,000 The Andes Mountains in South America, 167 00:17:41,000 --> 00:17:44,080 home to this continent's only bear. 168 00:17:46,960 --> 00:17:50,520 White facial markings are a clue to its name - 169 00:17:50,520 --> 00:17:52,440 the spectacled bear. 170 00:17:52,440 --> 00:17:55,840 But to many of us, it's far more familiar as the storybook 171 00:17:55,840 --> 00:17:57,920 character of Paddington. 172 00:18:03,000 --> 00:18:06,800 Like its fictional counterpart, this bear has a sweet tooth... 173 00:18:08,560 --> 00:18:13,360 ..although in these cloud forests, marmalade sandwiches 174 00:18:13,360 --> 00:18:15,120 aren't an option. 175 00:18:19,280 --> 00:18:22,480 Fortunately, there's another high-calorie food here... 176 00:18:26,640 --> 00:18:31,040 ..bromeliads - a family of plants that includes the pineapple. 177 00:18:35,080 --> 00:18:37,720 Growing metres off the ground, they're out of reach 178 00:18:37,720 --> 00:18:39,320 for most large mammals. 179 00:18:44,960 --> 00:18:49,880 Bromeliads are notoriously robust plants, but the spectacled bear 180 00:18:49,880 --> 00:18:52,040 can break them apart with ease. 181 00:18:58,360 --> 00:19:02,240 That's because, relative to its size, it has the largest jaw muscle 182 00:19:02,240 --> 00:19:07,880 of any bear species and grinding teeth that are secured into its jaws 183 00:19:07,880 --> 00:19:10,240 with three roots instead of two. 184 00:19:13,480 --> 00:19:15,680 It's after the sugar-rich core. 185 00:19:24,320 --> 00:19:27,040 The spectacled bear will also eat palm nuts, 186 00:19:27,040 --> 00:19:29,320 birds' eggs and small animals. 187 00:19:30,920 --> 00:19:34,600 But half of its diet is made up of these high-energy plants. 188 00:19:41,400 --> 00:19:44,760 Unfortunately, bromeliads tend to be widely scattered 189 00:19:44,760 --> 00:19:46,640 across this mountainous terrain... 190 00:19:55,040 --> 00:19:57,000 ..so these bears have to search 191 00:19:57,000 --> 00:19:59,040 their entire territory to find food... 192 00:20:01,480 --> 00:20:04,640 ..which can be up to 115 square miles. 193 00:20:07,640 --> 00:20:10,600 They have a surprising skill to help them. 194 00:20:13,200 --> 00:20:16,880 Research has shown that spectacled bears can remember the location 195 00:20:16,880 --> 00:20:21,080 of important resources by building up a mental map of the area. 196 00:20:31,600 --> 00:20:35,720 Higher up the mountain is the paramo - a land swathed 197 00:20:35,720 --> 00:20:36,960 in tall grasses. 198 00:20:39,160 --> 00:20:42,040 It's too cold for tree-growing bromeliads, 199 00:20:42,040 --> 00:20:44,160 but not too cold for puyas - 200 00:20:44,160 --> 00:20:48,800 giant ground bromeliads that can stand over three metres tall. 201 00:20:56,240 --> 00:20:57,880 But getting to their sugary centre 202 00:20:57,880 --> 00:21:00,080 requires a different technique. 203 00:21:10,840 --> 00:21:13,880 The spectacled bear can satisfy its need for calories 204 00:21:13,880 --> 00:21:17,560 by using its strength and its ability to find 205 00:21:17,560 --> 00:21:19,640 and remember food sources. 206 00:21:23,880 --> 00:21:28,320 But on the other side of the world, a very different habitat presents 207 00:21:28,320 --> 00:21:30,200 an even greater challenge. 208 00:21:34,080 --> 00:21:38,280 Across Asia, many of the forests are populated by one kind 209 00:21:38,280 --> 00:21:40,920 of plant - bamboo. 210 00:21:41,960 --> 00:21:45,200 In China alone, bamboo forests cover 211 00:21:45,200 --> 00:21:48,680 an area of over 20,000 square miles. 212 00:21:48,680 --> 00:21:51,520 But for an animal trying to make it here, 213 00:21:51,520 --> 00:21:53,720 there's just one problem. 214 00:21:56,720 --> 00:21:59,400 Bamboo is incredibly tough and fibrous 215 00:21:59,400 --> 00:22:02,480 and particularly low in calories. 216 00:22:10,200 --> 00:22:12,440 So, to conquer this landscape, 217 00:22:12,440 --> 00:22:15,880 one bear has done something quite extraordinary. 218 00:22:20,720 --> 00:22:23,800 The giant panda has adapted its body 219 00:22:23,800 --> 00:22:25,440 and even its behaviour 220 00:22:25,440 --> 00:22:28,840 to almost exclusively eat bamboo. 221 00:22:33,720 --> 00:22:37,320 The bear spends its days searching the Qinling Mountains for the most 222 00:22:37,320 --> 00:22:39,240 nutritious parts of the plant. 223 00:22:44,760 --> 00:22:46,800 It usually sits down to eat... 224 00:22:49,160 --> 00:22:51,240 ..so that its flexible forepaws 225 00:22:51,240 --> 00:22:53,480 are free to help harvest the bamboo. 226 00:22:57,760 --> 00:23:01,160 It's the only bear that has evolved a wrist bone to act as 227 00:23:01,160 --> 00:23:02,800 an opposable thumb... 228 00:23:04,240 --> 00:23:07,000 ..allowing it to select and manipulate the most tender 229 00:23:07,000 --> 00:23:08,680 part of the plant. 230 00:23:16,840 --> 00:23:19,560 To prevent injury from bamboo splinters, 231 00:23:19,560 --> 00:23:23,560 its oesophagus and stomach are lined with tough, thick walls. 232 00:23:26,480 --> 00:23:30,040 But its digestive system, like those of other bears, is built 233 00:23:30,040 --> 00:23:34,160 for eating meat, and it lacks the plant-digesting bacteria 234 00:23:34,160 --> 00:23:35,320 of a true herbivore. 235 00:23:43,960 --> 00:23:47,760 So, to get enough nutrients, it has to feed for up to 14 hours 236 00:23:47,760 --> 00:23:54,160 a day and chew its way through 12 kilos or more of bamboo. 237 00:23:56,840 --> 00:24:00,680 This low-energy diet also affects a panda's behaviour. 238 00:24:01,760 --> 00:24:06,920 To avoid exhaustion, it limits unnecessary socialising and walking 239 00:24:06,920 --> 00:24:09,080 in tricky terrain. 240 00:24:21,800 --> 00:24:23,560 Bamboo is evergreen, 241 00:24:23,560 --> 00:24:26,080 so the panda can eat all year round. 242 00:24:33,600 --> 00:24:37,840 It's even come up with a method of breaking ice off frozen leaves 243 00:24:37,840 --> 00:24:39,880 by using its warm snout. 244 00:24:47,640 --> 00:24:52,080 Fossil evidence suggests that pandas have been eating bamboo for the last 245 00:24:52,080 --> 00:24:57,560 four million years, but their complete dependence on one plant 246 00:24:57,560 --> 00:24:59,240 has put them in danger. 247 00:25:08,720 --> 00:25:13,480 Pandas once thrived across eastern and southern China 248 00:25:13,480 --> 00:25:16,360 but, as the forests made way for human development, 249 00:25:16,360 --> 00:25:20,440 their population crashed to just 1,000 bears. 250 00:25:22,080 --> 00:25:26,720 Today, their range is restricted to six isolated mountain ranges. 251 00:25:28,880 --> 00:25:33,120 Over the last six decades, efforts have been made to save the panda 252 00:25:33,120 --> 00:25:36,560 by giving them protection and setting up reserves. 253 00:25:39,200 --> 00:25:42,240 And in the early 1980s, China opened its first 254 00:25:42,240 --> 00:25:44,080 captive breeding centre. 255 00:25:50,200 --> 00:25:54,280 This programme has been very successful, with over 300 pandas 256 00:25:54,280 --> 00:25:55,680 born in captivity. 257 00:25:59,960 --> 00:26:02,760 Some of these are now being released into the wild. 258 00:26:09,720 --> 00:26:12,880 Work to bring this bear back from the brink of extinction 259 00:26:12,880 --> 00:26:14,520 is starting to pay off. 260 00:26:17,840 --> 00:26:20,960 Today, the wild population has nearly doubled 261 00:26:20,960 --> 00:26:23,720 to just over 1,800 pandas. 262 00:26:30,240 --> 00:26:34,880 An almost exclusively vegetarian diet is the exception for bears. 263 00:26:37,120 --> 00:26:42,640 Most need more protein to thrive, and they'll go to extreme lengths 264 00:26:42,640 --> 00:26:43,760 to get it. 265 00:26:49,240 --> 00:26:53,160 In India's dry grasslands, food is hard to come by. 266 00:26:57,880 --> 00:27:00,280 This fortress holds the answer. 267 00:27:02,280 --> 00:27:04,120 But how to get inside? 268 00:27:05,560 --> 00:27:08,080 The sloth bear is the real-life Baloo... 269 00:27:09,200 --> 00:27:11,800 ..the character in Rudyard Kipling's Jungle Book. 270 00:27:14,920 --> 00:27:18,080 Its distinctive shaggy coat made early explorers think 271 00:27:18,080 --> 00:27:24,000 it was a sloth, but it's the bear's powerful paws and unusual face 272 00:27:24,000 --> 00:27:26,880 which are key to how it gets its food. 273 00:27:37,000 --> 00:27:41,160 Under cover of darkness, it targets the mound's inhabitants... 274 00:27:44,040 --> 00:27:45,440 ..termites. 275 00:27:47,720 --> 00:27:51,240 They build these giant mounds, which are fortified by a wall 276 00:27:51,240 --> 00:27:52,640 of sun-baked clay. 277 00:27:56,040 --> 00:27:59,480 Most termites are less than two centimetres long, 278 00:27:59,480 --> 00:28:02,600 but there could be over a million of them inside. 279 00:28:11,360 --> 00:28:15,960 To get to them, the sloth bear has just the tools for the job. 280 00:28:17,440 --> 00:28:21,200 It uses eight centimetre-long claws to tear into the mound. 281 00:28:28,320 --> 00:28:32,360 Soldier termites have pincers, but they're no match for this bear's 282 00:28:32,360 --> 00:28:33,840 next form of attack. 283 00:28:40,000 --> 00:28:44,040 Long, floppy lips and a lack of front teeth allow it to use 284 00:28:44,040 --> 00:28:48,720 its mouth like a hoover and suck up hundreds of termites at a time. 285 00:28:56,480 --> 00:28:59,800 It can also shut its nostrils to avoid inhaling dirt 286 00:28:59,800 --> 00:29:01,520 or any stray insects. 287 00:29:06,640 --> 00:29:12,080 A sloth bear can demolish an entire termite colony in a single night. 288 00:29:19,200 --> 00:29:21,440 Rich in fat as well as protein, 289 00:29:21,440 --> 00:29:24,240 termites provide almost double the number of calories 290 00:29:24,240 --> 00:29:25,280 as a rump steak. 291 00:29:30,800 --> 00:29:35,120 Insects like these can form 95% of a sloth bear's diet. 292 00:29:38,360 --> 00:29:39,560 Around the world, 293 00:29:39,560 --> 00:29:43,400 physical adaptations allow different bear species to specialise 294 00:29:43,400 --> 00:29:45,440 on the most nutritious food available. 295 00:29:49,400 --> 00:29:50,920 In Southeast Asia, 296 00:29:50,920 --> 00:29:53,720 nothing is out of reach for the sun bear. 297 00:29:58,240 --> 00:30:01,280 Sickle-shaped claws and bare-soled feet 298 00:30:01,280 --> 00:30:04,760 mean it can access fruit in the jungle's tallest trees. 299 00:30:07,280 --> 00:30:10,000 Powerful paws expose insect larvae... 300 00:30:11,960 --> 00:30:16,280 ..and they use a 25 centimetre-long tongue to fish them out. 301 00:30:27,920 --> 00:30:29,280 Japan. 302 00:30:31,320 --> 00:30:34,160 On the rocky slopes of the Hida Mountains, 303 00:30:34,160 --> 00:30:38,360 an Asiatic black bear uses its sense of smell and careful 304 00:30:38,360 --> 00:30:40,640 footwork to uncover its prey... 305 00:30:42,280 --> 00:30:43,600 ..ants. 306 00:30:47,560 --> 00:30:51,240 It can spend up to eight hours a day flipping these rocks. 307 00:30:56,320 --> 00:31:00,360 When it comes to food, most bears show a remarkable level 308 00:31:00,360 --> 00:31:01,480 of resourcefulness... 309 00:31:03,120 --> 00:31:05,800 ..and that's just as well because the bears 310 00:31:05,800 --> 00:31:07,480 living in the Northern Hemisphere 311 00:31:07,480 --> 00:31:09,720 face a particularly difficult challenge. 312 00:31:13,560 --> 00:31:15,800 North America. 313 00:31:15,800 --> 00:31:19,600 In seasonal climates, the food available changes 314 00:31:19,600 --> 00:31:20,680 with the time of year... 315 00:31:22,520 --> 00:31:26,080 ..so bears like these grizzlies have to switch food sources 316 00:31:26,080 --> 00:31:27,200 every few weeks. 317 00:31:31,520 --> 00:31:33,320 Spring brings new growth. 318 00:31:37,760 --> 00:31:42,320 Succulent sedges and grasses provide a welcome protein boost. 319 00:31:46,480 --> 00:31:51,920 As summer approaches, seafood appears on the menu, but the bears 320 00:31:51,920 --> 00:31:53,400 need to plan ahead. 321 00:31:56,000 --> 00:31:58,080 They time their hunting during 322 00:31:58,080 --> 00:32:00,680 the 3-5 hour window of low tide. 323 00:32:03,320 --> 00:32:04,960 On the exposed sand, 324 00:32:04,960 --> 00:32:07,200 they detect their prey by smell. 325 00:32:11,640 --> 00:32:13,200 Clams. 326 00:32:21,000 --> 00:32:24,880 Grizzlies can eat as many as 100 clams in one low tide. 327 00:32:33,040 --> 00:32:37,280 They'll also gather seaweed, barnacles and mussels to add 328 00:32:37,280 --> 00:32:39,080 to their varied diet. 329 00:32:48,400 --> 00:32:49,800 But in early autumn, 330 00:32:49,800 --> 00:32:51,240 the bears' appetites 331 00:32:51,240 --> 00:32:52,840 suddenly go into overdrive. 332 00:32:55,360 --> 00:32:56,440 On the coast, 333 00:32:56,440 --> 00:32:59,800 this coincides with the appearance of a major food source. 334 00:33:06,000 --> 00:33:07,520 The salmon are back. 335 00:33:09,160 --> 00:33:12,600 Hormonal changes cause the bears to enter a phase 336 00:33:12,600 --> 00:33:15,200 of excessive eating, or hyperphagia. 337 00:33:17,280 --> 00:33:20,520 They eat almost continuously without ever feeling full. 338 00:33:22,360 --> 00:33:25,760 At this time of year, grizzlies can consume up to 100,000 339 00:33:25,760 --> 00:33:27,840 calories a day. 340 00:33:30,680 --> 00:33:33,920 That's the equivalent of over 1,000 boiled eggs. 341 00:33:40,280 --> 00:33:42,640 But this gluttony has a purpose. 342 00:33:52,960 --> 00:34:00,320 HOWLING 343 00:34:01,800 --> 00:34:04,280 As winter tightens its grip in the North... 344 00:34:06,640 --> 00:34:09,160 ..feeding opportunities begin to disappear. 345 00:34:23,120 --> 00:34:26,520 For many large animals, this can spell disaster. 346 00:34:33,040 --> 00:34:34,920 But bears have a solution. 347 00:34:37,320 --> 00:34:40,560 It's all down to an extraordinary feat of physiology. 348 00:34:45,320 --> 00:34:50,160 After their autumn feeding frenzy, they retreat to a den. 349 00:34:55,520 --> 00:34:58,560 Inside, they enter a state of hibernation. 350 00:35:03,120 --> 00:35:04,840 In this deep sleep, 351 00:35:04,840 --> 00:35:07,360 their body temperature drops several degrees 352 00:35:07,360 --> 00:35:11,200 and their heartbeat slows to as few as ten beats a minute. 353 00:35:23,640 --> 00:35:25,840 They don't eat or drink for seven months. 354 00:35:28,120 --> 00:35:32,960 Instead, they rely solely on their fat reserves to stay alive. 355 00:35:35,400 --> 00:35:39,480 Grizzlies, American, and Asiatic black bears all enter this 356 00:35:39,480 --> 00:35:42,480 deep form of hibernation in colder climes. 357 00:35:45,480 --> 00:35:48,640 They don't experience any heart complications, blood clots or 358 00:35:48,640 --> 00:35:52,400 even bone and muscle loss during this extended period of inactivity. 359 00:35:58,600 --> 00:36:02,040 The implications for human medicine are huge. 360 00:36:02,040 --> 00:36:05,680 NASA scientists are hoping the bears' biochemical secrets 361 00:36:05,680 --> 00:36:10,320 will one day help astronauts with long distance space travel. 362 00:36:10,320 --> 00:36:12,840 BIRDSONG 363 00:36:15,520 --> 00:36:19,680 With the arrival of spring, the bears emerge healthy and lean. 364 00:36:21,720 --> 00:36:26,200 After their long fast, they stock up in the meadows. 365 00:36:28,640 --> 00:36:31,680 Bears have had to adapt to make the most of the food available. 366 00:36:34,200 --> 00:36:37,240 But it's not the only challenge they face. 367 00:36:37,240 --> 00:36:41,560 Adult bears lead mostly solitary lives. 368 00:36:42,840 --> 00:36:45,160 And as the season warms up, 369 00:36:45,160 --> 00:36:48,760 many animals have just one thing on their mind. 370 00:36:53,520 --> 00:36:58,440 So, how does a bear find a mate? 371 00:37:01,720 --> 00:37:03,960 The answer involves trees... 372 00:37:06,000 --> 00:37:08,960 ..and a good old-fashioned back scratch. 373 00:37:20,840 --> 00:37:24,560 As they rub, they mark the tree with their scent. 374 00:37:26,040 --> 00:37:29,960 It's like leaving a calling card. 375 00:37:34,760 --> 00:37:37,400 The higher they can rub, the better. 376 00:37:37,400 --> 00:37:41,480 This way, their scent can travel further. 377 00:37:43,240 --> 00:37:46,000 And it doesn't take long for these chemical signals 378 00:37:46,000 --> 00:37:47,840 to attract other bears... 379 00:37:50,840 --> 00:37:53,320 ..who then leave their own messages. 380 00:37:58,240 --> 00:38:02,840 It's thought that this unusual form of communication helps 381 00:38:02,840 --> 00:38:08,120 individuals work out who's around, who to avoid and who's available. 382 00:38:11,480 --> 00:38:14,000 Now, all they need to do is get together. 383 00:38:20,160 --> 00:38:24,600 On the Alaskan coast, the dating game has moved to the next stage. 384 00:38:30,120 --> 00:38:33,120 Male and female grizzlies gather on the meadows. 385 00:38:34,400 --> 00:38:36,800 Some travel for hundreds of miles to be here. 386 00:38:43,120 --> 00:38:46,320 The big males show off with a strut... 387 00:38:46,320 --> 00:38:48,800 ..known as the cowboy walk. 388 00:38:50,440 --> 00:38:53,000 But there's more to this swagger than meets the eye. 389 00:38:54,400 --> 00:38:56,480 As they twist their paws into the grass, 390 00:38:56,480 --> 00:39:01,520 they leave behind a scent trail, made up of 26 volatile chemicals. 391 00:39:05,800 --> 00:39:08,440 The effect is enhanced with urine. 392 00:39:16,280 --> 00:39:20,040 These pungent scents and body postures signal the bear's 393 00:39:20,040 --> 00:39:24,960 intent to mate and help males establish a hierarchy. 394 00:39:26,800 --> 00:39:28,720 But when males are evenly matched, 395 00:39:28,720 --> 00:39:32,440 there's only one way to resolve their differences. 396 00:39:34,800 --> 00:39:38,360 GROWLING AND ROARING 397 00:40:03,960 --> 00:40:08,280 With the battle over, the victor can continue his courtship. 398 00:40:14,680 --> 00:40:18,880 In some parts of the world, finding a mate is even more challenging. 399 00:40:21,880 --> 00:40:23,560 The Arctic. 400 00:40:27,360 --> 00:40:32,760 Freezing temperatures and gale force winds make this land of snow and ice 401 00:40:32,760 --> 00:40:36,200 one of the most inhospitable places on the planet. 402 00:40:42,560 --> 00:40:45,560 But to a polar bear, it's home. 403 00:40:52,280 --> 00:40:55,960 Polar bears evolved from brown bears many thousands of years ago 404 00:40:55,960 --> 00:40:57,760 and spread north. 405 00:41:01,280 --> 00:41:03,840 Here, a lone male occupies 406 00:41:03,840 --> 00:41:05,600 a massive home range, 407 00:41:05,600 --> 00:41:08,920 sometimes in excess of 100,000 square miles. 408 00:41:13,760 --> 00:41:17,520 That's an area over 200 times bigger than Greater London. 409 00:41:20,320 --> 00:41:24,560 So, the chances of meeting a mate here seem vanishingly small. 410 00:41:31,320 --> 00:41:34,480 But this Arctic nomad has a strategy. 411 00:41:42,440 --> 00:41:44,160 In common with grizzlies, 412 00:41:44,160 --> 00:41:47,720 polar bears have sweat glands on the soles of their feet... 413 00:41:49,600 --> 00:41:52,600 ..so their footprints are full of information. 414 00:41:55,440 --> 00:41:58,480 All a male has to do is follow them. 415 00:42:00,600 --> 00:42:04,160 But his long distance trek is no guarantee of romance 416 00:42:04,160 --> 00:42:05,360 on the first date. 417 00:42:07,560 --> 00:42:10,440 When he finds her, he's got to impress. 418 00:42:12,920 --> 00:42:16,160 She'll only mate with him if she thinks he's fit and strong. 419 00:42:21,120 --> 00:42:23,600 So she puts him to the test. 420 00:42:29,640 --> 00:42:33,120 His downhill tobogganing lacks style, 421 00:42:33,120 --> 00:42:34,440 but he's keeping up. 422 00:42:39,160 --> 00:42:41,320 The next challenge is a rocky ascent. 423 00:42:44,200 --> 00:42:45,800 The female makes it look easy. 424 00:42:47,920 --> 00:42:52,080 Weighing almost twice as much as her, at close to half a tonne, 425 00:42:52,080 --> 00:42:54,360 size isn't on the male's side. 426 00:42:58,240 --> 00:43:00,520 He needs some encouragement. 427 00:43:00,520 --> 00:43:03,680 And she has a unique way of giving it. 428 00:43:10,880 --> 00:43:14,720 This is one of the few times that polar bears come together as adults. 429 00:43:17,440 --> 00:43:19,400 Courtship can last three weeks. 430 00:43:21,600 --> 00:43:23,520 Then, they'll go their separate ways. 431 00:43:29,520 --> 00:43:33,120 The female will spend the winter months under the snow, 432 00:43:33,120 --> 00:43:35,560 where she'll give birth to her cubs. 433 00:43:38,480 --> 00:43:41,360 And the male will endure the coldest weather that 434 00:43:41,360 --> 00:43:43,720 any bear on the planet must face. 435 00:43:48,400 --> 00:43:51,400 Temperatures will drop as low as minus 40 degrees. 436 00:43:52,880 --> 00:43:57,240 But this extraordinary bear has mastered the art of staying warm. 437 00:43:58,760 --> 00:44:02,520 A double-layered fur coat not only helps to keep out the cold, 438 00:44:02,520 --> 00:44:06,920 but it also keeps the heat in by trapping infrared radiation. 439 00:44:09,320 --> 00:44:14,560 And underneath is a layer of pure blubber, up to 11cm thick, 440 00:44:14,560 --> 00:44:16,400 which provides vital insulation. 441 00:44:18,840 --> 00:44:23,840 But to maintain its ample waistline, a polar bear needs high fat food... 442 00:44:26,160 --> 00:44:27,320 ..seals. 443 00:44:30,240 --> 00:44:33,240 And the best place to catch them is on the sea ice. 444 00:44:38,520 --> 00:44:42,360 This is where the seals create breathing holes and dens. 445 00:44:47,360 --> 00:44:49,360 The polar bear's sense of smell, 446 00:44:49,360 --> 00:44:52,920 said to be seven times more powerful than a bloodhound, 447 00:44:52,920 --> 00:44:56,480 can pick up the scent of a seal from over a mile away. 448 00:45:07,640 --> 00:45:09,840 To help it walk across the ice sheet, 449 00:45:09,840 --> 00:45:14,640 large paws act like snow shoes to spread the weight, 450 00:45:14,640 --> 00:45:17,320 while bumps of skin on the footpads 451 00:45:17,320 --> 00:45:20,160 and hairs between the toes provide grip. 452 00:45:31,800 --> 00:45:37,040 It can pinpoint its prey by smell 90cm beneath the ice. 453 00:45:53,960 --> 00:45:57,000 But seals are agile swimmers 454 00:45:57,000 --> 00:46:00,080 and nine out of ten hunts end in failure. 455 00:46:08,320 --> 00:46:12,120 There are successes and to survive, 456 00:46:12,120 --> 00:46:17,080 each bear must catch at least one adult seal every ten to 12 days. 457 00:46:22,400 --> 00:46:26,040 But, today, polar bears are facing a new challenge. 458 00:46:28,480 --> 00:46:33,720 With rising year-round temperatures, their hunting grounds are shrinking. 459 00:46:36,040 --> 00:46:39,760 Enormous masses of ice that were frozen for thousands of years 460 00:46:39,760 --> 00:46:42,320 have broken apart and melted away. 461 00:46:46,560 --> 00:46:52,800 Each year, the Arctic's frozen ocean is becoming smaller and thinner. 462 00:46:55,280 --> 00:46:58,680 Polar bears are being forced to swim ever greater distances 463 00:46:58,680 --> 00:47:00,320 to hunt seals. 464 00:47:08,120 --> 00:47:11,280 With their powers of endurance pushed to the limit, 465 00:47:11,280 --> 00:47:15,200 many will starve or even drown. 466 00:47:20,040 --> 00:47:22,520 If current trends continue, 467 00:47:22,520 --> 00:47:26,640 some scientists predict the summer sea ice in the Arctic could be 468 00:47:26,640 --> 00:47:30,640 gone within half a century and with it, 469 00:47:30,640 --> 00:47:33,440 potentially a third of all polar bears. 470 00:47:54,520 --> 00:47:56,280 In some parts of the Arctic, 471 00:47:56,280 --> 00:48:00,080 polar bears are trying to adapt to this changing world. 472 00:48:06,800 --> 00:48:10,440 Driven by hunger, the normally solitary bears have been 473 00:48:10,440 --> 00:48:13,680 filmed coming together to feed on our leftovers. 474 00:48:17,480 --> 00:48:20,800 It's a desperate and slightly alarming strategy. 475 00:48:25,240 --> 00:48:26,640 In today's world, 476 00:48:26,640 --> 00:48:29,720 people are increasingly encroaching on the wilderness. 477 00:48:37,120 --> 00:48:39,640 This is a problem for all animals. 478 00:48:39,640 --> 00:48:43,040 But the bears' opportunistic nature means many of them 479 00:48:43,040 --> 00:48:46,200 will try to take on this new challenge. 480 00:48:46,200 --> 00:48:48,800 SIREN WAILS 481 00:48:48,800 --> 00:48:53,400 Bears have an in-built curiosity and the largest brains, 482 00:48:53,400 --> 00:48:55,480 relative to body size, of all carnivores. 483 00:48:59,600 --> 00:49:02,000 They've discovered a way in to our world. 484 00:49:03,200 --> 00:49:05,880 LAUGHTER 485 00:49:05,880 --> 00:49:08,320 And cubs follow the lead of their mothers. 486 00:49:10,000 --> 00:49:14,000 With their dextrous paws, they are practically made for breaking 487 00:49:14,000 --> 00:49:15,520 and entering. 488 00:49:20,120 --> 00:49:25,440 Unlike many animals, they'll readily investigate anything new 489 00:49:25,440 --> 00:49:29,000 and quickly work out if it can be useful. 490 00:49:36,400 --> 00:49:40,360 Because of their broad diet, they thrive on our food. 491 00:49:43,680 --> 00:49:47,160 Some scientists believe that the bears' problem-solving abilities 492 00:49:47,160 --> 00:49:50,520 mean they should be ranked with monkeys, in terms of intelligence. 493 00:49:59,000 --> 00:50:02,360 And many of them have worked out that modern life can bring 494 00:50:02,360 --> 00:50:03,960 multiple benefits. 495 00:50:07,840 --> 00:50:10,080 The bear's right next to us! 496 00:50:10,080 --> 00:50:12,960 Where we live in such close proximity, 497 00:50:12,960 --> 00:50:16,440 our relationship with bears can at times be fraught. 498 00:50:16,440 --> 00:50:20,240 Oh, my goodness! Oh, my...! SCREAMS 499 00:50:23,600 --> 00:50:27,880 But there is a place where it's become almost harmonious. 500 00:50:31,200 --> 00:50:33,000 The north east coast of Japan... 501 00:50:35,920 --> 00:50:37,960 ..and the salmon are gathering offshore. 502 00:50:40,160 --> 00:50:42,000 Soon, they'll head inland to spawn. 503 00:50:50,040 --> 00:50:52,320 This is the Ussuri brown bear. 504 00:51:00,240 --> 00:51:02,040 They've been coming to these shores 505 00:51:02,040 --> 00:51:03,160 for centuries. 506 00:51:07,720 --> 00:51:10,000 More recently, the autumn bonanza 507 00:51:10,000 --> 00:51:13,440 of salmon has attracted other fishermen. 508 00:51:22,600 --> 00:51:25,000 Both of them are dependent on this food source. 509 00:51:30,440 --> 00:51:33,400 While the bears fish in the shallows, 510 00:51:33,400 --> 00:51:35,800 the fishermen target salmon out at sea. 511 00:51:40,720 --> 00:51:43,520 In the past, people here were more fearful of these animals 512 00:51:43,520 --> 00:51:45,320 and tried to fence them out. 513 00:51:48,240 --> 00:51:51,120 But the bears never became a threat 514 00:51:51,120 --> 00:51:56,680 and now around 200 peacefully share space with the human population. 515 00:51:59,440 --> 00:52:03,160 It's a unique relationship, where both can reap the rewards. 516 00:52:08,320 --> 00:52:11,360 In the modern world, bears and people will 517 00:52:11,360 --> 00:52:16,000 increasingly need to share space and resources like food and water. 518 00:52:19,760 --> 00:52:23,960 And, for bears, working out how to do this starts from a young age. 519 00:52:26,200 --> 00:52:31,760 Serranias del Burro, a mountainous region in Mexico's north east. 520 00:52:38,360 --> 00:52:43,360 It's home to the black bear, which is endangered in this country. 521 00:52:47,040 --> 00:52:48,600 For this family, 522 00:52:48,600 --> 00:52:51,600 the biggest challenge in the heat of summer isn't food... 523 00:52:54,880 --> 00:52:56,360 ..it's finding enough to drink. 524 00:52:57,680 --> 00:53:01,440 The underlying limestone rock soaks up the rain, 525 00:53:01,440 --> 00:53:04,200 leaving no permanent streams. 526 00:53:06,400 --> 00:53:08,440 Fortunately, there's another source, 527 00:53:08,440 --> 00:53:11,880 but reaching it requires skill and cunning. 528 00:53:19,640 --> 00:53:21,800 This is an area used for cattle grazing. 529 00:53:27,200 --> 00:53:30,120 The ranchers have set up watering holes by tapping into 530 00:53:30,120 --> 00:53:31,920 underground springs. 531 00:53:40,920 --> 00:53:42,880 The bears can take advantage of this, 532 00:53:42,880 --> 00:53:46,560 but the cattle are desperate for water too. 533 00:53:55,720 --> 00:53:59,000 They're naturally wary of potential predators 534 00:53:59,000 --> 00:54:01,320 and armed with sharp horns 535 00:54:01,320 --> 00:54:04,280 which could easily injury or even kill a bear. 536 00:54:22,560 --> 00:54:24,560 The livestock move off. 537 00:54:34,760 --> 00:54:37,560 The family finally have their chance to drink. 538 00:54:41,800 --> 00:54:43,240 But they're still not alone. 539 00:54:48,120 --> 00:54:49,840 It's a big male... 540 00:54:52,400 --> 00:54:54,040 ..and the cubs aren't safe. 541 00:55:05,280 --> 00:55:07,640 Their mother has taught them well. 542 00:55:16,080 --> 00:55:17,560 As the male cools off... 543 00:55:20,160 --> 00:55:21,680 ..they have to be patient. 544 00:55:23,480 --> 00:55:25,720 Finally, the coast is clear. 545 00:55:31,840 --> 00:55:34,640 The ranchers here are very tolerant of bears. 546 00:55:36,920 --> 00:55:39,680 They even provide a step up for the cubs. 547 00:55:54,520 --> 00:55:57,640 Weighing up the risks and taking advantage of 548 00:55:57,640 --> 00:56:01,440 new opportunities are vital skills for bear cubs to learn. 549 00:56:08,400 --> 00:56:12,400 All too soon, they will have to take their first steps towards 550 00:56:12,400 --> 00:56:16,680 independence and stand on their own two feet. 551 00:56:31,560 --> 00:56:35,520 After spending their early years in the care of their mother, 552 00:56:35,520 --> 00:56:38,640 young bears face a very different world. 553 00:56:43,320 --> 00:56:45,360 For the first time in their lives... 554 00:56:48,360 --> 00:56:49,840 ..they are alone. 555 00:56:59,120 --> 00:57:01,400 To be a bear takes a lot of skill. 556 00:57:05,680 --> 00:57:07,280 From avoiding danger... 557 00:57:08,880 --> 00:57:10,360 ..surviving the seasons... 558 00:57:11,760 --> 00:57:15,040 ..and learning to tackle whatever food is in front of them... 559 00:57:21,080 --> 00:57:23,640 ..and if they can do that, 560 00:57:23,640 --> 00:57:25,320 they'll reap the rewards. 561 00:57:35,040 --> 00:57:37,360 But the bears' biggest challenge yet... 562 00:57:40,040 --> 00:57:42,240 ..is today's rapidly changing world. 563 00:57:46,880 --> 00:57:52,120 Six of the eight species of bear are vulnerable to extinction. 564 00:57:55,080 --> 00:57:57,680 There is more pressure than ever on their habitats 565 00:57:57,680 --> 00:57:59,520 and the food they depend on. 566 00:58:01,960 --> 00:58:06,600 They'll need our help and our willingness to share space. 567 00:58:08,560 --> 00:58:11,200 If we give them the chance, 568 00:58:11,200 --> 00:58:15,080 their brains, brawn and ability to adapt... 569 00:58:16,560 --> 00:58:17,760 ..will do the rest.