WEBVTT 00:00:09.400 --> 00:00:12.186 Narrator: Autumn in Africa. 00:00:12.229 --> 00:00:16.059 The changing season brings new opportunities. 00:00:17.234 --> 00:00:20.672 For some, rain offers relief 00:00:20.716 --> 00:00:24.067 and a chance to escape summer's heat. 00:00:24.111 --> 00:00:26.113 On the ocean floor, 00:00:26.156 --> 00:00:29.507 falling temperatures signal a time to feast. 00:00:31.379 --> 00:00:35.035 While, along the coast, giants hunt. 00:00:36.862 --> 00:00:40.170 As the days grows shorter, predators cash in. 00:00:42.955 --> 00:00:46.916 Deep in the undergrowth, tiny warriors emerge... 00:00:48.309 --> 00:00:51.181 ...and the competition to breed heats up. 00:00:54.315 --> 00:00:59.233 Autumn is a season of mammoth migrations 00:00:59.276 --> 00:01:01.757 and miniature love affairs 00:01:01.800 --> 00:01:07.067 for the creatures living through Africa's wild year. 00:01:50.414 --> 00:01:54.418 In the Southern Hemisphere, summer is drawing to a close. 00:02:01.512 --> 00:02:04.602 The Earth's axis tilts further from the sun 00:02:04.646 --> 00:02:07.127 and marks the transition into autumn. 00:02:10.739 --> 00:02:13.742 Days become shorter 00:02:13.785 --> 00:02:15.613 and the weather becomes drier. 00:02:21.010 --> 00:02:23.491 This is the season for the natural world 00:02:23.534 --> 00:02:25.797 to prepare for the cold months of winter... 00:02:30.585 --> 00:02:33.762 ...and store energy for the leaner times ahead. 00:02:49.169 --> 00:02:52.389 It's late March and, off the coast of South Africa, 00:02:52.433 --> 00:02:56.915 70,000 Cape fur seals cram together on a single island. 00:03:05.402 --> 00:03:08.797 The 12,000 pups born here five months earlier 00:03:08.840 --> 00:03:10.320 are now fully weaned. 00:03:12.496 --> 00:03:14.106 The arrival of autumn marks 00:03:14.150 --> 00:03:16.196 their first season of independence. 00:03:19.634 --> 00:03:23.986 To survive, the adolescent seals must now feed themselves. 00:03:28.643 --> 00:03:32.647 And that means heading into treacherous open water, 00:03:32.690 --> 00:03:34.866 away from the island's sanctuary. 00:03:42.178 --> 00:03:44.702 The rich feeding grounds of the Atlantic Ocean are 00:03:44.746 --> 00:03:46.008 on their doorstep. 00:03:52.667 --> 00:03:56.279 But they are not the only predators in these waters 00:03:56.323 --> 00:03:57.541 looking for a meal. 00:04:04.200 --> 00:04:07.508 Another formidable hunter is circling the island. 00:04:09.118 --> 00:04:11.338 A great white shark is on the lookout 00:04:11.381 --> 00:04:12.774 for her next meal. 00:04:15.037 --> 00:04:18.910 Autumn draws large numbers of great whites to these waters, 00:04:18.954 --> 00:04:21.435 attracted by the promise of an easy meal. 00:04:25.352 --> 00:04:28.398 As the young seals venture offshore for the first time, 00:04:28.442 --> 00:04:30.922 their naiveté makes them vulnerable. 00:04:34.012 --> 00:04:36.406 They make the perfect prey for a great white -- 00:04:36.450 --> 00:04:39.061 high in energy-rich fat and muscle. 00:04:42.282 --> 00:04:46.198 A deep channel lies between the island and the open ocean. 00:04:46.242 --> 00:04:50.159 The great white patrols the depths, waiting to strike. 00:04:54.990 --> 00:04:57.340 If the adolescent seals are to feed, 00:04:57.384 --> 00:05:00.082 they have no choice but to cross the channel first. 00:05:03.564 --> 00:05:06.088 It gives the shark the perfect opportunity 00:05:06.131 --> 00:05:07.916 to launch a high-speed attack. 00:05:12.442 --> 00:05:14.966 A group of adults head to the feeding grounds first. 00:05:18.405 --> 00:05:20.363 They are incredibly agile. 00:05:20.407 --> 00:05:23.366 Flexible spines and streamlined flippers 00:05:23.410 --> 00:05:25.325 help them turn in a split second. 00:05:28.937 --> 00:05:31.679 The seals stick close together in a tight group, 00:05:31.722 --> 00:05:34.812 making it harder for the shark to identify a target. 00:05:37.467 --> 00:05:40.949 The more experienced seals rely on an early warning system 00:05:40.992 --> 00:05:42.603 to help them detect an attack. 00:05:46.998 --> 00:05:48.696 As a shark builds up speed, 00:05:48.739 --> 00:05:51.612 it pushes a large amount of water in front of its nose. 00:05:53.440 --> 00:05:55.398 The seals sense the change in water pressure 00:05:55.442 --> 00:05:57.966 and react quickly, changing direction. 00:06:01.926 --> 00:06:05.103 They are too fast for the shark to change course 00:06:05.147 --> 00:06:07.236 and she misses her target. 00:06:07.279 --> 00:06:08.150 This time. 00:06:16.811 --> 00:06:20.510 Ultimately, less than half of shark hunts prove successful. 00:06:23.731 --> 00:06:25.689 But the shark has another chance. 00:06:28.083 --> 00:06:30.477 She turns her focus to a new target. 00:06:32.653 --> 00:06:35.525 A group of adolescents lingr in the safety of the shallows. 00:06:37.397 --> 00:06:38.920 But driven by hunger, 00:06:38.963 --> 00:06:41.836 they must now run the gantlet across the deep channel. 00:06:43.403 --> 00:06:46.014 This may be their first time encountering a great white. 00:06:47.798 --> 00:06:49.713 The youngsters don't have the experience 00:06:49.757 --> 00:06:51.367 of the oldest seals in the colony... 00:06:53.978 --> 00:06:56.198 ...and the group quickly starts to split up. 00:07:03.423 --> 00:07:05.555 The shark launches its attack from the deep, 00:07:05.599 --> 00:07:08.428 reaching a speed of 25 miles per hour 00:07:08.471 --> 00:07:09.864 just below the surface. 00:07:11.474 --> 00:07:13.868 The impact of the attack stuns the seal 00:07:13.911 --> 00:07:17.828 and gives the great white time to turn and finish the kill. 00:07:21.963 --> 00:07:26.054 Forty-eight serrated teeth make light work of the marine mammal. 00:07:44.986 --> 00:07:46.770 The arrival of autumn will test 00:07:46.814 --> 00:07:49.730 the seal colony's youngsters to the limit. 00:07:51.688 --> 00:07:54.038 They must learn how to detect and evade 00:07:54.082 --> 00:07:57.825 the danger from the deep, if they are to survive. 00:08:09.271 --> 00:08:12.013 Inland, the transition into autumn 00:08:12.056 --> 00:08:13.710 heralds the arrival of rain 00:08:13.754 --> 00:08:15.756 in many parts of Southern Africa. 00:08:17.279 --> 00:08:19.890 The residual heat of summer collides 00:08:19.934 --> 00:08:23.372 with cold fronts rolling in from the coast, 00:08:23.415 --> 00:08:26.418 creating thunderstorms that sweep across the land. 00:08:31.554 --> 00:08:33.600 The rain triggers a burst of growth, 00:08:33.643 --> 00:08:35.689 regenerating grasslands. 00:08:38.039 --> 00:08:40.389 It's a chance for grazers to bulk up. 00:08:44.219 --> 00:08:46.613 But as temperatures continue to fall, 00:08:46.656 --> 00:08:48.658 the rains will eventually stop... 00:08:51.139 --> 00:08:54.708 ...and many will face a long, dry, winter. 00:09:06.023 --> 00:09:08.373 For now, there's a glut of food. 00:09:12.552 --> 00:09:14.684 And, with the rain, mud. 00:09:33.007 --> 00:09:36.793 Wallowing is fun as well as functional for this buffalo. 00:09:42.582 --> 00:09:44.758 Mud is nature's sunblock. 00:09:45.889 --> 00:09:48.109 It also doubles as insect repellent. 00:09:51.199 --> 00:09:54.550 As the mud dries, it forms a layer on the buffalo's hide... 00:09:56.073 --> 00:09:58.293 ...providing relief on hot days. 00:10:00.643 --> 00:10:02.558 When the mud eventually falls off... 00:10:03.864 --> 00:10:06.170 ...it takes irritating parasites with it. 00:10:18.095 --> 00:10:21.403 The rains bring temporary relief for the buffalo, 00:10:21.446 --> 00:10:23.057 as well as many other inhabitants 00:10:23.100 --> 00:10:24.928 of Southern Africa's bushveld. 00:10:33.458 --> 00:10:34.329 April. 00:10:35.852 --> 00:10:37.593 And, for another creature, 00:10:37.637 --> 00:10:40.683 the arrival of autumn mars a change in diet. 00:10:45.993 --> 00:10:48.778 The Amatola Mountains in the Eastern Cape 00:10:48.822 --> 00:10:50.867 are home to some of the last remaining 00:10:50.911 --> 00:10:53.130 montane forests on the continent. 00:11:02.009 --> 00:11:04.620 This is the refuge of the samango monkey... 00:11:08.668 --> 00:11:10.234 ...South Africa's only 00:11:10.278 --> 00:11:12.149 exclusively forest-dwellig primate. 00:11:19.896 --> 00:11:22.856 But the spread of farming and timber plantations 00:11:22.899 --> 00:11:25.946 is threatening the future of this rare species. 00:11:34.345 --> 00:11:36.434 With their habitat shrinking, 00:11:36.478 --> 00:11:39.568 the samango monkey is now vulnerable to extinction. 00:11:45.661 --> 00:11:50.013 In order to survive, this family has had to learn to adapt. 00:11:57.455 --> 00:11:59.501 They've developed resourceful strategies 00:11:59.544 --> 00:12:01.111 in their search for food 00:12:01.155 --> 00:12:04.593 and autumn is one of their busiest times of year. 00:12:05.986 --> 00:12:08.640 With winter approaching, nutritious food is 00:12:08.684 --> 00:12:11.469 in short supply in the Amatola Mountains. 00:12:11.513 --> 00:12:15.735 But beyond the forest boundary, a bounty awaits. 00:12:17.171 --> 00:12:19.695 The troop sets off in search of breakfast, 00:12:19.739 --> 00:12:21.131 led by the alpha male. 00:12:25.919 --> 00:12:28.748 What they are after lies deep in suburbia. 00:12:34.275 --> 00:12:39.193 Early European settlers planted hazelnut hedges, fruit trees, 00:12:39.236 --> 00:12:43.066 berry canes, and oaks to remind themselves of home. 00:12:46.287 --> 00:12:48.550 Native to the Northern Hemisphere, 00:12:48.593 --> 00:12:50.160 the recent drop in temperature 00:12:50.204 --> 00:12:53.076 has triggered many of the trees' nuts to ripen. 00:12:55.078 --> 00:12:59.474 In Europe and North America, squirrels, deer, and chipmunks 00:12:59.517 --> 00:13:01.868 depend on these as a staple food source. 00:13:03.870 --> 00:13:07.917 But here, the samangos have the feast to themselves. 00:13:11.878 --> 00:13:14.968 If they can work out a way to safely reach them. 00:13:17.884 --> 00:13:19.581 In their way is a road. 00:13:21.278 --> 00:13:22.932 And they know it's dangerous. 00:13:25.587 --> 00:13:29.330 In previous years, monkeys have paid with their lives. 00:13:32.942 --> 00:13:35.945 Some choose a different route and head high. 00:13:45.346 --> 00:13:49.698 It's a precarious balancing act, even for these agile climbers. 00:14:10.937 --> 00:14:13.983 Safely across, the troop head for the trees. 00:14:20.685 --> 00:14:21.904 The acorns and pine nuts 00:14:21.948 --> 00:14:24.341 are packed with nutrient-rich calories. 00:14:28.955 --> 00:14:32.132 The troop gorge themselves on the autumn glut. 00:14:37.659 --> 00:14:41.141 The extra energy will help them store fat before the winter. 00:14:55.851 --> 00:14:57.070 On the floor below, 00:14:57.113 --> 00:15:00.203 the fallen leaves hide small insects, 00:15:00.247 --> 00:15:02.031 an important source of protein. 00:15:15.044 --> 00:15:18.308 Once full, some of the troop take time out to bond... 00:15:24.314 --> 00:15:26.969 ...while others head deeper into the suburbs, 00:15:27.013 --> 00:15:28.710 in search of more variety. 00:15:31.060 --> 00:15:33.628 A young male hits the jackpot. 00:15:37.458 --> 00:15:38.589 An orange tree. 00:15:48.991 --> 00:15:50.950 After checking the coast is clear, 00:15:50.993 --> 00:15:52.603 he heads for his prize. 00:15:55.998 --> 00:15:58.783 Samango monkeys are highly adaptable 00:15:58.827 --> 00:16:00.829 and can digest different food types. 00:16:06.748 --> 00:16:08.706 Across the seasons, 00:16:08.750 --> 00:16:11.883 it allows them to make the mot of whatever's on offer 00:16:11.927 --> 00:16:12.972 and thrive. 00:16:16.801 --> 00:16:18.673 In a changing landscape, 00:16:18.716 --> 00:16:21.458 it means they can also exploit their human neighbors. 00:16:29.379 --> 00:16:32.643 The troop makes the return journey as night falls. 00:16:34.471 --> 00:16:37.735 They head back to the security of the forest, 00:16:37.779 --> 00:16:38.823 where they'll sleep. 00:16:54.448 --> 00:16:56.015 It's now late April 00:16:56.058 --> 00:16:58.234 and, as temperatures continue to drop, 00:16:58.278 --> 00:17:00.062 the thunderstorms that bring rain 00:17:00.106 --> 00:17:03.283 to large areas of Southern Africa disappear. 00:17:10.159 --> 00:17:13.119 On the coast, the relentless offshore gusts 00:17:13.162 --> 00:17:15.773 that pound the coast throughout the summer 00:17:15.817 --> 00:17:17.384 also begin to ease. 00:17:23.129 --> 00:17:27.785 With the arrival of autumn in a hidden underwater forest, 00:17:27.829 --> 00:17:29.135 calm falls. 00:17:36.055 --> 00:17:37.621 Kelp provides a sanctuary 00:17:37.665 --> 00:17:40.059 for a myriad of underwater species. 00:17:44.802 --> 00:17:46.195 Red roman fish... 00:17:47.588 --> 00:17:48.719 ...sea urchins... 00:17:50.939 --> 00:17:54.899 ...and pyjama sharks all shelter here, 00:17:54.943 --> 00:17:58.164 alongside a very rare forest inhabitant. 00:18:00.949 --> 00:18:02.429 Coated in seaweed, 00:18:02.472 --> 00:18:05.214 it's perfectly camouflaged on the ocean floor. 00:18:08.826 --> 00:18:12.569 Abalone are an endangered species of marine snail. 00:18:20.142 --> 00:18:22.318 Its large muscular foot 00:18:22.362 --> 00:18:25.713 propels it forward in search of algae to feed on. 00:18:31.153 --> 00:18:33.721 The outer edge is a sensory organ covered 00:18:33.764 --> 00:18:35.462 by a host of tentacles. 00:18:39.205 --> 00:18:42.251 The flat shell is covered in a set of holes used 00:18:42.295 --> 00:18:44.384 to push water through to the gills. 00:18:51.478 --> 00:18:53.828 But they also serve another purpose. 00:18:56.222 --> 00:18:59.399 Autumn is the abalone's breeding season. 00:19:09.452 --> 00:19:12.020 This male flushes billions of sperm 00:19:12.063 --> 00:19:14.588 through the holes in its shell into the water. 00:19:17.678 --> 00:19:19.767 As they float close to the female, 00:19:19.810 --> 00:19:21.464 she starts to contract 00:19:21.508 --> 00:19:24.075 and squeezes out millions of her eggs, 00:19:24.119 --> 00:19:25.686 ready to be fertilized. 00:19:29.994 --> 00:19:32.432 Autumn's calm waters are crucial 00:19:32.475 --> 00:19:36.305 for giving the breeding abalone the best chance of success. 00:19:46.054 --> 00:19:49.144 Only one in 10,000 fertilized eggs 00:19:49.188 --> 00:19:51.146 will make it to the larval stage. 00:20:03.419 --> 00:20:06.988 Those that do survive will live out their lives 00:20:07.031 --> 00:20:09.991 in this pristine underwater forest. 00:20:19.218 --> 00:20:22.308 250 miles off the African mainland, 00:20:22.351 --> 00:20:26.225 the island of Madagascar has an entirely different climate. 00:20:30.620 --> 00:20:33.144 The wet season is coming to an end here, 00:20:33.188 --> 00:20:37.061 but temperatures remain between 75° and 85. 00:20:39.977 --> 00:20:42.676 This helps create a lush, tropical environment 00:20:42.719 --> 00:20:44.243 for the island's inhabitants. 00:20:49.117 --> 00:20:51.337 Isolated from the mainland 00:20:51.380 --> 00:20:53.774 for 88 million years, 00:20:53.817 --> 00:20:56.907 life here has evolved in unique ways. 00:21:09.224 --> 00:21:12.445 Four hundred species of reptile live on the island, 00:21:12.488 --> 00:21:16.231 90% of which are found nowhere else on earth. 00:21:22.063 --> 00:21:25.588 Including an incredible variety of chameleons. 00:21:32.987 --> 00:21:35.946 April is the start of their mating season 00:21:35.990 --> 00:21:38.558 and, across the island, male chameleons 00:21:38.601 --> 00:21:40.342 are securing their territory 00:21:40.386 --> 00:21:43.302 to give themselves the best chance of success. 00:21:55.139 --> 00:21:59.970 This male Parson's chameleon has already staked his claim. 00:22:00.014 --> 00:22:02.712 Now, he's on the lookout for a female. 00:22:10.416 --> 00:22:14.289 This is the largest species of chameleon in the world. 00:22:20.164 --> 00:22:21.905 At around two feet long, 00:22:21.949 --> 00:22:24.821 he's a fearsome proposition to other chameleons... 00:22:29.173 --> 00:22:31.219 ...and is unlikely to be disturbed. 00:22:35.528 --> 00:22:38.313 But even with romance on his mind, 00:22:38.357 --> 00:22:39.836 he still needs to eat. 00:22:45.059 --> 00:22:47.278 With both eyes fixed on his target, 00:22:47.322 --> 00:22:51.500 he unleashes his deadly tongue at a speed of 16 feet a second. 00:22:55.548 --> 00:22:57.724 He's an ambush predator, 00:22:57.767 --> 00:23:00.335 engulfing his prey with a swift kill. 00:23:05.688 --> 00:23:07.429 While he enjoys lunch, 00:23:07.473 --> 00:23:09.475 the rest of the chameleon community 00:23:09.518 --> 00:23:11.128 is abuzz with activity. 00:23:17.483 --> 00:23:20.747 These lizards are masters of camouflage, 00:23:20.790 --> 00:23:23.532 able to change color to match their background. 00:23:25.665 --> 00:23:27.841 But there's more to this remarkable ability 00:23:27.884 --> 00:23:29.190 than just blending in. 00:23:34.195 --> 00:23:37.241 It's also a form of visual communication... 00:23:38.808 --> 00:23:40.723 ...allowing them to convey their mood... 00:23:42.203 --> 00:23:43.465 ...body temperature, 00:23:43.509 --> 00:23:45.902 and even if they are ready to mate. 00:23:51.255 --> 00:23:55.564 A panther chameleon suddenly spots a potential challenger. 00:23:57.305 --> 00:24:00.439 It's a young rival male climbing onto his branch. 00:24:14.627 --> 00:24:17.630 The larger male approaches to investigate. 00:24:17.673 --> 00:24:21.111 His vibrant color portrays his anger at the intruder. 00:24:26.726 --> 00:24:29.642 The smaller male realizes he's outranked... 00:24:32.775 --> 00:24:34.081 ...and signals his submission 00:24:34.124 --> 00:24:36.431 by dialing down his bright tones. 00:25:01.412 --> 00:25:03.632 But the victor still isn't satisfied 00:25:03.676 --> 00:25:05.504 and chases the challenger away. 00:25:28.744 --> 00:25:31.094 The young chameleon will have to look elsewhere 00:25:31.138 --> 00:25:33.662 in the forest for a territory of his own. 00:25:47.589 --> 00:25:49.286 With the onset of autumn, 00:25:49.330 --> 00:25:53.160 sea temperatures along the coast of KwaZulu-Natal in South Africa 00:25:53.203 --> 00:25:54.291 begin to fall. 00:25:56.206 --> 00:25:58.992 It's the trigger for some animals to migrate. 00:26:04.432 --> 00:26:09.568 A hawksbill turtle senses it's time to seek out warmer waters. 00:26:12.614 --> 00:26:14.747 She relies on the environment around her 00:26:14.790 --> 00:26:16.836 to regulate her internal temperature. 00:26:23.146 --> 00:26:26.410 If the temperatures are too cold, she won't survive. 00:26:37.291 --> 00:26:39.815 She begins her long migration north, 00:26:39.859 --> 00:26:42.992 following the warm currents of the Indian Ocean. 00:27:09.149 --> 00:27:11.891 And she's not the only animal on the move. 00:27:20.203 --> 00:27:24.599 This ragged-tooth shark is also on her annual autumn migration. 00:27:27.080 --> 00:27:30.692 But while the turtle is moving north to escape the cold, 00:27:30.736 --> 00:27:33.826 she's moving south to find cooler temperatures. 00:27:43.270 --> 00:27:46.752 She's completing a 600-mile round trip back 00:27:46.795 --> 00:27:49.276 to the cold waters of her breeding grounds... 00:27:52.105 --> 00:27:56.152 ...where her journey will culminate in a remarkable event. 00:27:57.197 --> 00:27:59.852 While some shark species lay eggs, 00:27:59.895 --> 00:28:02.506 other species give birth to live young. 00:28:05.553 --> 00:28:07.990 The ragged-tooth female is pregnant 00:28:08.034 --> 00:28:10.384 and, after ten months' gestation, 00:28:10.427 --> 00:28:13.953 she's ready to bring new life into the world. 00:28:27.531 --> 00:28:29.751 She's joined by other females. 00:28:39.500 --> 00:28:44.723 They may appear calm, but inside, a battle is raging. 00:28:49.466 --> 00:28:53.383 The gestation of their shark pups is a violent affair. 00:28:56.343 --> 00:29:01.000 Initially, the embryos are fed by an internal supply of yolk, 00:29:01.043 --> 00:29:02.784 which helps them grow strong. 00:29:04.960 --> 00:29:07.049 But once the yolk runs out, 00:29:07.093 --> 00:29:10.531 the larger pups feed on the other developing embryos. 00:29:15.797 --> 00:29:18.626 Until only the strongest two survive. 00:29:21.542 --> 00:29:25.241 Autumn signals the culmination of the hard-won battle. 00:29:43.390 --> 00:29:46.045 It's April and, while the ragged-tooth sharks 00:29:46.088 --> 00:29:47.437 prepare to give birth... 00:29:49.091 --> 00:29:51.833 ...a pair of harlequin shrimp are getting ready for winter. 00:29:58.884 --> 00:30:00.450 They are on the hunt 00:30:00.494 --> 00:30:02.670 and they have very specific tastes. 00:30:07.893 --> 00:30:09.242 Starfish. 00:30:12.985 --> 00:30:16.031 Except, this hunt doesn't end in death. 00:30:20.557 --> 00:30:23.996 During winter, starfish are harder to come by, 00:30:24.039 --> 00:30:26.389 as they move offshore to deeper waters. 00:30:28.174 --> 00:30:29.871 So, the harlequin shrimp have evolved 00:30:29.915 --> 00:30:32.831 a bizarre method to avoid a food shortage. 00:30:38.662 --> 00:30:40.882 With winter fast approaching, 00:30:40.926 --> 00:30:43.493 these two harlequin shrimp are stocking up... 00:30:44.799 --> 00:30:46.714 ...in a rather sinister way. 00:30:48.368 --> 00:30:50.761 The male and female work together 00:30:50.805 --> 00:30:54.504 to overpower the starfish by flipping it onto its back 00:30:54.548 --> 00:30:56.898 before using their claws to pierce 00:30:56.942 --> 00:30:59.858 the tough covering of the starfish limb, 00:30:59.901 --> 00:31:02.295 to expose the soft flesh inside. 00:31:07.648 --> 00:31:11.695 With the starfish upside-down and unable to escape, 00:31:11.739 --> 00:31:14.698 they begin to eat the invertebrate alive. 00:31:16.744 --> 00:31:18.659 They start at the tip of the arm, 00:31:18.702 --> 00:31:20.356 working their way along, 00:31:20.400 --> 00:31:22.576 until they reach the central disk. 00:31:24.317 --> 00:31:26.972 But it doesn't kill the starfish straightaway. 00:31:28.016 --> 00:31:30.062 Starfish have special stem cells 00:31:30.105 --> 00:31:32.064 that allow their limbs to regenerate. 00:31:38.070 --> 00:31:39.158 The shrimp have evolved 00:31:39.201 --> 00:31:40.942 to keep the starfish alive 00:31:40.986 --> 00:31:42.465 as long as possible. 00:31:43.858 --> 00:31:46.600 By not killing them, and leaving some limbs intact, 00:31:46.643 --> 00:31:50.386 they can prolong their supply of food and feast... 00:31:54.390 --> 00:31:58.177 ...a big advantage with winter's lean months on the horizon. 00:32:14.845 --> 00:32:18.197 Autumn has long been associated with harvests 00:32:18.240 --> 00:32:21.504 and a time to build energy reserves before winter sets in. 00:32:25.944 --> 00:32:29.556 But, unlike their counterparts in the Northern Hemisphere, 00:32:29.599 --> 00:32:33.168 Southern Africa's animals don't hibernate in the colder months. 00:32:40.393 --> 00:32:43.874 Instead, some of them take advantage of the shifting season 00:32:43.918 --> 00:32:45.180 to multiply. 00:32:52.100 --> 00:32:53.884 After the autumn equinox, 00:32:53.928 --> 00:32:56.235 the gap between sunset and moonrise 00:32:56.278 --> 00:32:57.801 is the shortest in the year. 00:33:00.979 --> 00:33:06.114 It's called the harvest moon and it means more light. 00:33:12.164 --> 00:33:16.037 It's late April and the first full moon of the season. 00:33:22.826 --> 00:33:27.701 In South Africa's Western Cape. this is a time for romance. 00:33:32.793 --> 00:33:36.797 Autumn's misty nights and the abundant moonlight combine 00:33:36.840 --> 00:33:38.668 to lure frogs out of hiding. 00:34:02.692 --> 00:34:07.741 These Cape rain frogs are not the most agile of amphibians. 00:34:11.701 --> 00:34:13.312 They dehydrate easily... 00:34:15.575 --> 00:34:18.186 ...so they rely on damp nights to mate. 00:34:26.151 --> 00:34:27.587 Unlike other frogs, 00:34:27.630 --> 00:34:30.938 who can mount each other in more traditional ways, 00:34:30.981 --> 00:34:34.942 their limbs are too short and their bodies are too... 00:34:34.985 --> 00:34:35.725 chubby. 00:34:41.644 --> 00:34:44.256 And it doesn't help that the female is larger. 00:34:48.434 --> 00:34:50.349 Which presents a bit of a problem, 00:34:50.392 --> 00:34:51.437 when it comes to mating. 00:34:54.309 --> 00:34:57.443 So, they've had to evolve a different approach. 00:35:01.055 --> 00:35:03.579 The females secretes a special glue 00:35:03.623 --> 00:35:06.234 which stops the male from sliding off... 00:35:08.541 --> 00:35:11.457 ...allowing him to fertilize her eggs externally. 00:35:13.502 --> 00:35:16.723 Unusually, she doesn't lay her eggs in water, 00:35:16.766 --> 00:35:18.072 but underground. 00:35:19.334 --> 00:35:21.554 Instead of turning into tadpoles, 00:35:21.597 --> 00:35:23.599 after around eight weeks, 00:35:23.643 --> 00:35:25.688 they will hatch straight into frogs. 00:35:27.125 --> 00:35:30.867 The Cape rain frogs' courtship might not be pretty, 00:35:30.911 --> 00:35:33.261 but, it gets the job done. 00:35:45.882 --> 00:35:50.148 As April turns to May, winter looms on the horizon. 00:35:59.331 --> 00:36:01.463 Animals that take longer to produce young 00:36:01.507 --> 00:36:04.292 need to mate before winter arrives, 00:36:04.336 --> 00:36:07.817 so their offspring will be born in the abundance of spring. 00:36:14.563 --> 00:36:17.218 Autumn is their time to attract a mate. 00:36:22.441 --> 00:36:25.618 For this male impala, that means rutting. 00:36:29.143 --> 00:36:32.712 He must prove he's the strongest male in the grasslands. 00:36:45.333 --> 00:36:46.769 As the days get shorter 00:36:46.813 --> 00:36:48.641 and the nights get longer, 00:36:48.684 --> 00:36:51.383 his testosterone levels skyrocket. 00:36:54.386 --> 00:36:56.779 If he can prove he's the dominant male, 00:36:56.823 --> 00:36:59.304 he'll win the exclusive breeding rights 00:36:59.347 --> 00:37:01.349 to his own harem of females. 00:37:15.494 --> 00:37:16.712 A fight breaks out. 00:37:23.980 --> 00:37:26.548 A wrong move could result in a broken neck 00:37:26.592 --> 00:37:28.071 or a fatal wound. 00:37:44.262 --> 00:37:46.264 The loser is banished. 00:37:48.744 --> 00:37:50.877 He'll have to join a separate bachelor herd, 00:37:50.920 --> 00:37:52.618 with other weaker males, 00:37:52.661 --> 00:37:55.490 until he can claim a herd of females of his own. 00:37:58.188 --> 00:38:00.669 But the Victor's job is far from over. 00:38:02.454 --> 00:38:04.673 Until the mating season finishes, 00:38:04.717 --> 00:38:07.154 he'll continue to fight off suitors 00:38:07.197 --> 00:38:10.200 as they vie for a shot at taking his harem over. 00:38:18.426 --> 00:38:20.385 A restless month lies ahead. 00:38:29.481 --> 00:38:31.134 By late autumn, 00:38:31.178 --> 00:38:33.702 the sun's strength has weakened in Southern Africa. 00:38:38.794 --> 00:38:40.840 As May turns to June, 00:38:40.883 --> 00:38:44.017 the early season rains are a distant memory. 00:38:48.021 --> 00:38:50.632 This is the start of the dry season. 00:38:55.724 --> 00:38:58.336 The savannah turns to its winter hue... 00:39:01.077 --> 00:39:04.080 ...making the camouflage of an elusive cat 00:39:04.124 --> 00:39:05.995 even more effective. 00:39:10.304 --> 00:39:11.610 The caracal. 00:39:20.880 --> 00:39:24.057 She's the master of bushveld espionage... 00:39:29.541 --> 00:39:32.413 ...which isn't good news for her prey, 00:39:32.457 --> 00:39:34.197 a fully grown guinea fowl. 00:39:37.810 --> 00:39:42.031 Thick fur on her foot pads silence her approach. 00:39:47.602 --> 00:39:50.039 She needs to get within striking distance. 00:40:01.660 --> 00:40:05.707 Powerful hind legs help her jump over six feet in the air. 00:40:14.629 --> 00:40:15.717 A pounce! 00:40:15.761 --> 00:40:17.240 And it's all over. 00:40:23.638 --> 00:40:26.075 The feathers offer little nutritional value. 00:40:36.869 --> 00:40:40.699 She uses her fine front teeth to strip them away 00:40:40.742 --> 00:40:42.396 and reach the flesh beneath. 00:41:00.545 --> 00:41:02.503 But she must eat quickly. 00:41:02.547 --> 00:41:05.463 Her meal could be stolen by larger predators in the area. 00:41:11.120 --> 00:41:15.560 Each of her ears is controlled by approximately 20 muscles, 00:41:15.603 --> 00:41:19.781 helping her to hone in on prey and any approaching threats. 00:41:23.263 --> 00:41:27.310 The dry season ushers in a time of plenty for big predators. 00:41:28.486 --> 00:41:31.967 Game becomes easier to see through the drying vegetation, 00:41:32.011 --> 00:41:34.579 as it concentrates around water sources, 00:41:34.622 --> 00:41:36.624 making hunting easier. 00:41:40.585 --> 00:41:44.806 With the onset of the winter dry season and shortening days, 00:41:44.850 --> 00:41:46.547 there's also a drop in temperature 00:41:46.591 --> 00:41:47.592 across the savannah. 00:41:51.900 --> 00:41:55.077 This sets in motion a series of events deep 00:41:55.121 --> 00:41:56.557 in the earth below. 00:42:07.916 --> 00:42:10.789 These harvester termites are in full swing, 00:42:10.832 --> 00:42:12.007 preparing for winter. 00:42:20.799 --> 00:42:23.628 Underground, they have thousands of mouths to feed. 00:42:25.847 --> 00:42:27.849 It will take a coordinated effort 00:42:27.893 --> 00:42:29.851 for the colony to be ready in time. 00:42:33.333 --> 00:42:35.030 It's all hands on deck. 00:42:37.990 --> 00:42:39.644 The termites harvest grass 00:42:39.687 --> 00:42:44.039 to transport it to storage chambers 19 feet below ground... 00:42:45.824 --> 00:42:49.175 ...supplies that will feed the colony throughout winter. 00:42:52.439 --> 00:42:54.702 If they have the muscle power, that is. 00:43:03.711 --> 00:43:08.586 Their queen is capable of laying up to 25,000 eggs a day, 00:43:08.629 --> 00:43:10.065 so their work is cut out. 00:43:14.679 --> 00:43:16.376 To meet the demand, 00:43:16.419 --> 00:43:18.944 the colony labor force is divided into roles. 00:43:25.690 --> 00:43:28.736 Cutters use their powerful, serrated mandibles 00:43:28.780 --> 00:43:31.478 to make short work of the grass, 00:43:31.521 --> 00:43:33.698 while workers haul the clippings away. 00:44:06.078 --> 00:44:07.688 Across the savannah, 00:44:07.732 --> 00:44:10.343 the undergrowth is a hive of activity. 00:44:17.306 --> 00:44:19.308 The autumnal drop in temperatures 00:44:19.352 --> 00:44:21.354 forces many from the underworld 00:44:21.397 --> 00:44:24.096 to come to the surface to gather supplies. 00:44:30.145 --> 00:44:32.365 These fungus-growing termites 00:44:32.408 --> 00:44:35.237 are collecting their nutrients from elephant dung, 00:44:35.281 --> 00:44:38.806 in order to cultivate a fungus on which the colony feed. 00:44:46.945 --> 00:44:50.470 They are far from their colony, and vulnerable, 00:44:50.513 --> 00:44:51.906 with nowhere to hide. 00:44:56.084 --> 00:44:59.000 A raiding party of Matabele ants strike. 00:45:03.222 --> 00:45:06.094 They feed exclusively on termites 00:45:06.138 --> 00:45:09.358 and autumn has provided them with a glut of food. 00:45:14.581 --> 00:45:16.844 It's a strategic and methodical attack. 00:45:22.676 --> 00:45:25.461 The smaller ants seek out the underground colony, 00:45:25.505 --> 00:45:27.246 flushing the termites out, 00:45:27.289 --> 00:45:29.639 while the larger ants lie in wait. 00:45:40.172 --> 00:45:42.740 The subterranean warriors make short work 00:45:42.783 --> 00:45:44.785 of the exposed termites 00:45:44.829 --> 00:45:46.874 and return to their nest with their pillage. 00:45:48.833 --> 00:45:51.226 Precious energy for the winter ahead, 00:45:51.270 --> 00:45:53.576 when the termites are harder to find. 00:46:22.867 --> 00:46:25.391 The increased activity on the savannah floor 00:46:25.434 --> 00:46:27.132 has not gone unnoticed. 00:46:41.102 --> 00:46:43.409 An ant wanders off its trail 00:46:43.452 --> 00:46:45.846 and straight into a minefield. 00:46:56.422 --> 00:47:01.253 A web of sunken traps dug by antlion larvae 00:47:01.296 --> 00:47:03.298 to catch unsuspecting prey. 00:47:07.172 --> 00:47:09.696 Autumn's flurry of insect activity 00:47:09.739 --> 00:47:12.307 has triggered the tiny predators into action. 00:47:15.745 --> 00:47:19.445 Strong, venom-filled pincers wait at the bottom 00:47:19.488 --> 00:47:21.795 to catch any unlucky visitors. 00:47:38.464 --> 00:47:42.990 Once an ant falls in the trap, the antlion larvae flick sand, 00:47:43.034 --> 00:47:45.297 making it harder for the ant to escape. 00:47:52.957 --> 00:47:54.306 The trap is working. 00:47:59.920 --> 00:48:01.922 The ant fights to escape the jaws. 00:48:11.540 --> 00:48:15.066 But another flick of sand sends it sliding back down again. 00:48:22.116 --> 00:48:25.293 Once firmly in the larvae's vise-like grip, 00:48:25.337 --> 00:48:27.208 it doesn't stand a chance. 00:48:41.005 --> 00:48:44.138 This is the last chance for the larvae to feast. 00:48:44.182 --> 00:48:45.661 When winter arrives, 00:48:45.705 --> 00:48:48.229 they will burrow deeper underground 00:48:48.273 --> 00:48:50.579 and remain inactive until spring. 00:49:13.820 --> 00:49:16.562 Autumn triggers changes in the life cycles 00:49:16.605 --> 00:49:18.607 of many in the animal kingdom. 00:49:23.917 --> 00:49:26.354 Rare creatures have revealed themselves 00:49:26.398 --> 00:49:29.270 and predators have gathered to take advantage. 00:49:33.883 --> 00:49:37.061 As this short window of opportunity closes, 00:49:37.104 --> 00:49:38.497 the dry season sweeps 00:49:38.540 --> 00:49:41.587 across large swathes of Southern Africa. 00:49:47.897 --> 00:49:51.249 The new season will challenge all life. 00:49:54.078 --> 00:49:55.514 Over the coming months, 00:49:55.557 --> 00:49:59.257 winter will bring a dramatic conclusion 00:49:59.300 --> 00:50:02.129 to Africa's wild year.