1 00:00:23,691 --> 00:00:26,319 There's something magical about dolphins. 2 00:00:30,990 --> 00:00:32,909 They appear so friendly. 3 00:00:35,453 --> 00:00:37,205 Yet so otherworldly. 4 00:00:41,250 --> 00:00:43,294 They're clearly intelligent. 5 00:00:46,756 --> 00:00:47,840 And agile. 6 00:00:56,808 --> 00:01:00,686 But we've still barely glimpsed beneath the surface. 7 00:01:05,983 --> 00:01:08,861 Now we can immerse ourselves in their world, 8 00:01:09,529 --> 00:01:12,698 we're discovering just how sophisticated they are. 9 00:01:21,457 --> 00:01:23,084 And the deeper we look, 10 00:01:24,335 --> 00:01:25,878 the more like us they seem. 11 00:01:52,738 --> 00:01:56,159 Born into a world where he can't even breathe, 12 00:01:57,827 --> 00:01:59,787 a young Atlantic spotted dolphin 13 00:01:59,871 --> 00:02:02,790 has a lot to learn about surviving at sea. 14 00:02:06,878 --> 00:02:09,755 A good thing he has someone to show him the way. 15 00:02:13,926 --> 00:02:14,760 Mom. 16 00:02:19,557 --> 00:02:22,685 And a wider group of family and friends. 17 00:02:39,035 --> 00:02:40,912 They'll help teach him 18 00:02:41,704 --> 00:02:43,206 how to find food… 19 00:02:45,291 --> 00:02:47,835 and how to avoid danger. 20 00:02:54,300 --> 00:02:56,677 But dolphin society is complicated. 21 00:02:58,137 --> 00:02:59,805 The greatest challenge 22 00:02:59,889 --> 00:03:02,016 is learning how to fit in. 23 00:03:15,071 --> 00:03:17,365 These warm, shallow waters 24 00:03:17,448 --> 00:03:19,909 are also home to another species. 25 00:03:21,827 --> 00:03:23,621 Bottlenose dolphins. 26 00:03:31,254 --> 00:03:35,508 This might seem the perfect place for a mother to raise her newborn calf… 27 00:03:37,635 --> 00:03:38,594 but even here, 28 00:03:39,303 --> 00:03:41,097 life isn't easy. 29 00:03:49,397 --> 00:03:51,023 They're being followed. 30 00:03:55,778 --> 00:03:57,196 A group of males, 31 00:03:58,114 --> 00:03:59,615 looking for a mate. 32 00:04:02,827 --> 00:04:05,663 They could attack the baby to get to Mom. 33 00:04:18,009 --> 00:04:20,177 More dolphins join the chase. 34 00:04:28,394 --> 00:04:31,314 Mom does all she can to protect her calf. 35 00:04:39,238 --> 00:04:40,323 Eventually, 36 00:04:40,948 --> 00:04:42,325 she fights them off. 37 00:04:45,703 --> 00:04:47,747 But her baby is nowhere to be seen. 38 00:04:58,049 --> 00:05:01,177 Alone, he stands little chance. 39 00:05:25,951 --> 00:05:28,371 Reunited with Mom… 40 00:05:30,539 --> 00:05:32,083 and her allies, 41 00:05:33,459 --> 00:05:37,546 the calf a little wiser in the ways of the world. 42 00:05:39,131 --> 00:05:43,719 But his lessons in becoming a dolphin have only just begun. 43 00:05:57,900 --> 00:06:01,278 Dolphins are air-breathing mammals, like us. 44 00:06:03,989 --> 00:06:07,076 Their ancestors once lived on dry land, 45 00:06:08,702 --> 00:06:10,955 but 50 million years ago, 46 00:06:11,038 --> 00:06:13,165 they did something amazing. 47 00:06:14,875 --> 00:06:16,168 Left the land 48 00:06:16,252 --> 00:06:19,296 to enter a life aquatic. 49 00:06:24,176 --> 00:06:25,845 While one branch of the family 50 00:06:25,928 --> 00:06:29,557 became huge, filter-feeding baleen whales… 51 00:06:31,976 --> 00:06:34,728 they turned into streamlined, 52 00:06:34,812 --> 00:06:36,939 quick-thinking predators. 53 00:06:39,817 --> 00:06:44,488 Today, over 40 species of dolphin hunt the oceans of the world. 54 00:06:50,077 --> 00:06:51,996 From tropical waters… 55 00:06:55,958 --> 00:06:57,877 to polar seas, 56 00:06:59,462 --> 00:07:03,591 and even in rivers thousands of miles inland, 57 00:07:05,509 --> 00:07:07,303 wherever there is prey, 58 00:07:08,429 --> 00:07:11,849 there's a dolphin with a clever way of catching it. 59 00:07:21,484 --> 00:07:24,945 Orca are the largest members of the family. 60 00:07:27,198 --> 00:07:29,867 They can grow nearly 30 feet long 61 00:07:30,409 --> 00:07:33,162 and weigh seven tons. 62 00:07:37,833 --> 00:07:41,504 Each needs to catch over 100 lb. of food a day. 63 00:07:43,756 --> 00:07:45,841 Not easy in the polar winter. 64 00:07:46,967 --> 00:07:49,261 Unless you know where to look. 65 00:08:02,733 --> 00:08:04,652 During the coldest months, 66 00:08:04,735 --> 00:08:07,988 their favorite prey shelters in protected fjords. 67 00:08:13,786 --> 00:08:14,703 Herring. 68 00:08:16,038 --> 00:08:19,124 In their billions. 69 00:08:31,387 --> 00:08:33,973 Tracking down their exact location 70 00:08:34,056 --> 00:08:35,224 can be tricky. 71 00:08:39,603 --> 00:08:41,564 Catching them is even harder. 72 00:08:51,031 --> 00:08:53,325 Led by an experienced female, 73 00:08:54,451 --> 00:08:58,664 the family pod home in on the vast shoal. 74 00:09:02,293 --> 00:09:04,587 As long as the herring keep formation, 75 00:09:05,963 --> 00:09:07,756 they're hard to single out. 76 00:09:18,934 --> 00:09:20,811 But the orca have a plan. 77 00:09:24,106 --> 00:09:26,317 With pulsing calls, 78 00:09:27,276 --> 00:09:29,528 and by flashing their white bellies… 79 00:09:32,448 --> 00:09:35,409 they herd the herring into the shallows. 80 00:09:50,507 --> 00:09:54,345 In the panic, the fish form tighter and tighter shoals. 81 00:10:04,396 --> 00:10:06,023 Until finally, 82 00:10:06,106 --> 00:10:08,651 the orca can strike. 83 00:10:19,828 --> 00:10:24,166 Smashing their tail flukes creates powerful pressure waves. 84 00:10:29,213 --> 00:10:31,799 A barrage of knockout blows. 85 00:10:39,598 --> 00:10:41,475 Once the fish are stunned, 86 00:10:42,267 --> 00:10:45,020 the orca can eat at leisure. 87 00:11:09,086 --> 00:11:13,340 Dolphins maximize their hunting success by working as a team. 88 00:11:15,259 --> 00:11:17,177 And out in the open ocean, 89 00:11:17,261 --> 00:11:19,555 they operate on an epic scale. 90 00:11:25,102 --> 00:11:28,272 A stampede of spinner dolphins. 91 00:11:30,566 --> 00:11:34,236 A super pod over a thousand strong. 92 00:11:51,128 --> 00:11:54,089 They make such an effective hunting force, 93 00:11:54,798 --> 00:11:57,885 they can afford plenty of downtime. 94 00:12:11,648 --> 00:12:13,484 {\an8}Two hundred miles east of Brazil, 95 00:12:14,651 --> 00:12:17,196 this archipelago is a favorite stop-off 96 00:12:17,279 --> 00:12:19,239 for Atlantic spinner dolphins. 97 00:12:22,951 --> 00:12:25,412 They head for the island's shallow bays. 98 00:12:28,624 --> 00:12:32,461 The first arrivals are in high spirits. 99 00:12:47,976 --> 00:12:51,104 The Olympic gymnasts of the dolphin family. 100 00:12:52,439 --> 00:12:55,400 They can leap ten feet 101 00:12:56,276 --> 00:12:58,320 and spin seven times. 102 00:13:11,166 --> 00:13:12,793 It looks a lot of fun. 103 00:13:15,087 --> 00:13:18,257 But it's thought there's more to these acrobatics. 104 00:13:26,139 --> 00:13:28,225 Perhaps they're communicating, 105 00:13:28,308 --> 00:13:30,811 greeting other dolphins entering the bay. 106 00:13:45,868 --> 00:13:47,661 With safety in numbers, 107 00:13:48,495 --> 00:13:50,664 the spinners can relax. 108 00:14:02,509 --> 00:14:04,720 But they can't switch off completely, 109 00:14:05,470 --> 00:14:07,055 or they would drown. 110 00:14:08,432 --> 00:14:11,810 So they shut down one side of their brain at a time… 111 00:14:13,896 --> 00:14:16,315 with one eye on where they're going. 112 00:14:18,233 --> 00:14:20,861 Sleep swimming at half speed. 113 00:14:27,659 --> 00:14:30,037 While older dolphins rest, 114 00:14:31,413 --> 00:14:34,041 the younger ones play. 115 00:14:56,521 --> 00:14:58,523 A game of seaweed catch. 116 00:15:28,261 --> 00:15:30,430 It seems simple enough. 117 00:15:33,850 --> 00:15:37,396 But this is surprisingly sophisticated play. 118 00:15:39,606 --> 00:15:41,692 Manipulating objects, 119 00:15:43,068 --> 00:15:46,154 copying moves and, most importantly, 120 00:15:46,238 --> 00:15:47,823 understanding each other. 121 00:15:48,907 --> 00:15:54,496 A skill every young dolphin must master as it grows. 122 00:16:00,377 --> 00:16:02,254 By a year old, 123 00:16:02,337 --> 00:16:06,717 an Atlantic spotted calf is almost fluent in dolphin. 124 00:16:22,232 --> 00:16:25,652 Much can be communicated through body language and touch. 125 00:16:27,738 --> 00:16:29,823 A flipper rub reassures, 126 00:16:30,824 --> 00:16:32,325 like holding hands. 127 00:16:35,412 --> 00:16:39,416 But some things can only be said with sound. 128 00:16:43,003 --> 00:16:45,005 His mom repeats a unique call. 129 00:16:48,842 --> 00:16:50,343 Her signature whistle. 130 00:16:53,472 --> 00:16:55,807 It helps him to find her in a crowd. 131 00:17:00,645 --> 00:17:02,939 And once he's learned to copy it, 132 00:17:03,023 --> 00:17:04,900 he can call her by her name. 133 00:17:08,070 --> 00:17:11,615 Now it's time to experiment with a whistle of his own. 134 00:17:16,495 --> 00:17:17,788 Like children, 135 00:17:17,871 --> 00:17:20,707 dolphins take years learning to speak. 136 00:17:23,168 --> 00:17:25,128 And once they start talking… 137 00:17:28,298 --> 00:17:30,884 …they never let up. 138 00:17:38,266 --> 00:17:42,229 But a dolphin's sonic skills go way beyond words. 139 00:17:48,151 --> 00:17:51,947 The local bottlenose are searching for food on the sea floor. 140 00:17:54,116 --> 00:17:56,076 There doesn't appear to be much here. 141 00:17:57,869 --> 00:18:02,040 But they can see things we can't. 142 00:18:09,381 --> 00:18:12,467 They fire a stream of high-pitched clicks. 143 00:18:13,677 --> 00:18:16,638 Five hundred per second. 144 00:18:24,688 --> 00:18:26,690 And interpret the echoes 145 00:18:26,773 --> 00:18:29,609 to pinpoint fish hiding in the sand. 146 00:18:52,424 --> 00:18:55,844 Echolocation is an extraordinary sixth sense… 147 00:18:57,888 --> 00:19:03,185 that allows dolphins to hunt in the most unlikely of places. 148 00:19:15,155 --> 00:19:16,448 A muddy estuary, 149 00:19:17,490 --> 00:19:20,076 and the tide is dropping. 150 00:19:21,745 --> 00:19:25,999 Right now, heading inland could be a risky move. 151 00:19:38,720 --> 00:19:43,308 But this dolphin knows the estuary is full of fish. 152 00:19:53,944 --> 00:19:55,946 Using echolocation, 153 00:19:56,029 --> 00:20:00,659 she can navigate the silty waters and find her prey. 154 00:20:08,708 --> 00:20:10,293 Only problem is, 155 00:20:10,377 --> 00:20:13,338 at low tide they hide in the oyster beds. 156 00:20:15,257 --> 00:20:18,343 Charging in would shred her sensitive skin. 157 00:20:20,804 --> 00:20:25,141 Somehow, she needs to get the fish into the open. 158 00:20:38,863 --> 00:20:42,784 Pumping her tail, she flushes them out of hiding 159 00:20:43,868 --> 00:20:47,289 and towards the sandy banks, where it's safe to strike. 160 00:20:55,755 --> 00:20:58,883 Only a few dolphins have learned to hunt like this. 161 00:21:03,722 --> 00:21:05,807 And the technique only works 162 00:21:05,890 --> 00:21:08,101 for a few hours each day. 163 00:21:14,774 --> 00:21:17,360 When the tide begins to rise, 164 00:21:17,444 --> 00:21:19,362 the fish disperse. 165 00:21:22,741 --> 00:21:24,659 A new strategy is needed. 166 00:21:28,705 --> 00:21:30,707 She joins forces with friends 167 00:21:32,042 --> 00:21:35,503 and together they head towards wider channels. 168 00:21:39,549 --> 00:21:40,550 Then, 169 00:21:42,427 --> 00:21:43,636 they wait. 170 00:22:28,056 --> 00:22:30,266 Each time a shoal swims past, 171 00:22:30,350 --> 00:22:32,227 the dolphins attack, 172 00:22:33,895 --> 00:22:37,023 creating bow waves that wash the fish ashore. 173 00:22:54,624 --> 00:22:58,378 Through echolocation and coordination, 174 00:22:58,461 --> 00:23:01,548 they conjure a feast from the mud. 175 00:23:08,304 --> 00:23:10,306 Out in the big blue, 176 00:23:10,390 --> 00:23:13,810 dolphins must push their super senses to the limits. 177 00:23:21,151 --> 00:23:23,027 The challenge of hunting in the abyss 178 00:23:23,111 --> 00:23:27,824 has created one of the most extraordinary dolphins of all. 179 00:23:48,511 --> 00:23:51,097 Pilot whales may look strange, 180 00:23:51,806 --> 00:23:55,935 but their bulbous foreheads hold the secret to their success. 181 00:23:57,187 --> 00:24:01,274 They project long-range sonic beams hundreds of feet. 182 00:24:02,317 --> 00:24:05,820 The most powerful echolocation of any dolphin. 183 00:24:10,283 --> 00:24:13,036 {\an8} 184 00:24:13,745 --> 00:24:16,873 {\an8}It enables pilot whales to hunt shoals of squid 185 00:24:16,956 --> 00:24:19,083 over half a mile down. 186 00:24:29,469 --> 00:24:33,181 But young calves can't hold their breath long enough to follow. 187 00:24:37,560 --> 00:24:40,688 So the family take turns 188 00:24:40,772 --> 00:24:42,732 babysitting at the surface. 189 00:24:45,985 --> 00:24:48,696 Grandma is over 50 years old. 190 00:24:50,031 --> 00:24:53,368 But she still produces milk to keep the youngsters fed. 191 00:25:02,460 --> 00:25:05,922 These dolphins live up to 70 years 192 00:25:06,923 --> 00:25:09,217 and stay with the family for life. 193 00:25:10,093 --> 00:25:15,014 Possibly the longest, most loyal bonds of any animal. 194 00:25:22,480 --> 00:25:24,649 When the hunting party surfaces, 195 00:25:24,732 --> 00:25:26,734 it's clear they've had success. 196 00:25:32,824 --> 00:25:34,409 Time to move on. 197 00:25:35,785 --> 00:25:38,913 Grandma has a mental map of their ocean home. 198 00:25:40,039 --> 00:25:43,835 She listens for the sounds of waves crashing on islands 199 00:25:43,918 --> 00:25:46,588 and currents washing around sea mouths. 200 00:25:49,591 --> 00:25:52,385 Acoustic landmarks revealing the route. 201 00:25:59,392 --> 00:26:00,602 But sometimes, 202 00:26:01,853 --> 00:26:04,355 even these great navigators lose their way. 203 00:26:09,819 --> 00:26:10,695 Every year, 204 00:26:11,696 --> 00:26:15,325 hundreds of dolphins strand on beaches around the world. 205 00:26:16,284 --> 00:26:18,828 Pilot whales more often than most. 206 00:26:20,997 --> 00:26:23,958 It only takes one or two to go off course… 207 00:26:26,044 --> 00:26:29,589 and family members feel compelled to swim to their side. 208 00:26:33,176 --> 00:26:36,304 Sometimes, their distress calls bring hundreds more. 209 00:26:44,479 --> 00:26:46,397 Natural disasters, 210 00:26:46,481 --> 00:26:48,858 noise pollution, and ill health 211 00:26:48,941 --> 00:26:51,110 all seem to play a part. 212 00:26:53,613 --> 00:26:57,241 {\an8}But the exact triggers for these events are poorly understood. 213 00:26:57,325 --> 00:26:59,327 {\an8} 214 00:27:04,666 --> 00:27:08,169 {\an8}People do all they can to keep stranded whales alive 215 00:27:08,252 --> 00:27:10,963 and try to help them back out to sea. 216 00:27:20,473 --> 00:27:24,018 The connection between humans and dolphins runs deep. 217 00:27:25,728 --> 00:27:30,149 We share a thrill-seeking side found in few other animals. 218 00:27:31,275 --> 00:27:36,280 And we express ourselves in ways that have no obvious role in survival. 219 00:27:41,077 --> 00:27:43,871 But it seems there's purpose to all this play. 220 00:27:46,332 --> 00:27:48,710 It produces a rush of hormones 221 00:27:48,793 --> 00:27:51,963 that create feelings of confidence and joy. 222 00:27:53,673 --> 00:27:56,926 Playing together heightens these emotions… 223 00:27:59,095 --> 00:28:03,057 encouraging teamwork and time spent with friends. 224 00:28:17,113 --> 00:28:20,408 Perhaps this is why dolphins seek the company of others. 225 00:28:34,797 --> 00:28:36,924 Playing with their own kind. 226 00:28:41,763 --> 00:28:42,597 With us. 227 00:28:46,601 --> 00:28:48,603 And with other animals. 228 00:29:15,379 --> 00:29:18,299 Dolphins are famous for their friendly nature. 229 00:29:20,468 --> 00:29:22,887 But they also have a darker side. 230 00:29:36,651 --> 00:29:39,987 When the ocean's top predators go hunting, 231 00:29:40,071 --> 00:29:42,114 nothing is safe. 232 00:30:01,634 --> 00:30:04,220 Southern right whales. 233 00:30:06,347 --> 00:30:08,599 Up to 80 tons. 234 00:30:10,101 --> 00:30:12,895 Ten times heavier than an orca. 235 00:30:21,362 --> 00:30:23,155 But working as a team, 236 00:30:24,115 --> 00:30:26,784 orca are almost unstoppable. 237 00:30:32,081 --> 00:30:34,500 The right whales make for the shallows 238 00:30:34,584 --> 00:30:36,586 to avoid attack from below. 239 00:30:40,923 --> 00:30:43,801 But orca don't give up easily. 240 00:30:48,055 --> 00:30:49,891 Taking turns, 241 00:30:49,974 --> 00:30:52,894 they smash into the whales' flanks, 242 00:30:52,977 --> 00:30:54,687 hitting them where it hurts. 243 00:31:05,072 --> 00:31:07,116 The whales strike back. 244 00:31:35,061 --> 00:31:39,190 But it's only when the sounds of struggle attract more right whales 245 00:31:40,733 --> 00:31:43,736 that the orca finally back off. 246 00:31:50,576 --> 00:31:53,329 Orca's ability to take on such large prey 247 00:31:53,412 --> 00:31:55,957 earned them the nickname "whale killers," 248 00:31:56,624 --> 00:31:57,458 or 249 00:31:58,209 --> 00:31:59,418 "killer whales." 250 00:32:02,922 --> 00:32:05,341 Dolphins are not just ruthless hunters. 251 00:32:06,634 --> 00:32:10,221 They can also be surprisingly aggressive to each other. 252 00:32:24,402 --> 00:32:25,653 By six years old, 253 00:32:26,237 --> 00:32:28,197 this young spotted dolphin 254 00:32:28,280 --> 00:32:31,409 has finally developed his trademark spots. 255 00:32:37,373 --> 00:32:39,041 He's seeing less of Mom… 256 00:32:41,085 --> 00:32:44,296 and spending more time hanging out with friends. 257 00:32:48,884 --> 00:32:52,555 Building alliances is crucial in these early years. 258 00:33:02,773 --> 00:33:06,610 Dolphins form more numerous, more intense relationships 259 00:33:06,694 --> 00:33:09,864 than any other animal except us. 260 00:33:14,994 --> 00:33:18,205 As he matures, life will become more complicated. 261 00:33:22,126 --> 00:33:24,628 And he'll need all the friends he can get. 262 00:33:36,766 --> 00:33:40,352 A community of bottlenose dolphins in Western Australia 263 00:33:40,436 --> 00:33:45,357 is considered the most sophisticated dolphin society of all. 264 00:33:48,319 --> 00:33:50,988 Two thousand live in this one bay. 265 00:34:02,124 --> 00:34:04,251 During the breeding season, 266 00:34:04,335 --> 00:34:07,713 who you know becomes more important than ever. 267 00:34:09,757 --> 00:34:11,675 Males that are able to team up 268 00:34:11,759 --> 00:34:14,011 have more chance of winning a mate. 269 00:34:28,359 --> 00:34:31,237 This trio hangs out on the east side of the bay. 270 00:34:37,535 --> 00:34:41,539 They've been best friends for 20 years. 271 00:34:44,834 --> 00:34:49,296 Swimming in sync shows just how tight they are. 272 00:34:51,757 --> 00:34:55,845 And choreographed moves help impress the opposite sex. 273 00:35:02,935 --> 00:35:04,645 There's the crossover. 274 00:35:07,273 --> 00:35:08,482 The butterfly. 275 00:35:12,111 --> 00:35:13,946 The duo tail touch. 276 00:35:16,157 --> 00:35:17,992 Synchronous dives. 277 00:35:20,161 --> 00:35:21,537 Dual leaps. 278 00:35:22,997 --> 00:35:24,582 Tango moves. 279 00:35:25,249 --> 00:35:29,044 And the inverse rooster strut. 280 00:35:32,256 --> 00:35:36,010 The slicker the routine, the more attractive they seem. 281 00:35:41,557 --> 00:35:42,808 Even so, 282 00:35:42,892 --> 00:35:45,561 it often takes days to win over a female. 283 00:35:51,692 --> 00:35:54,403 And now they have competition. 284 00:35:56,530 --> 00:35:57,907 On the west side, 285 00:35:57,990 --> 00:36:00,117 rival gangs are forming. 286 00:36:03,412 --> 00:36:05,706 The east side trio needs backup. 287 00:36:09,001 --> 00:36:11,795 So they call on a wider circle of friends. 288 00:36:31,440 --> 00:36:33,234 Weaker gangs usually back down. 289 00:36:35,611 --> 00:36:37,988 But when the sides are equally matched, 290 00:36:39,365 --> 00:36:41,825 fights can cause serious injury. 291 00:37:30,082 --> 00:37:31,083 An hour later, 292 00:37:32,167 --> 00:37:33,377 it's all over. 293 00:37:38,299 --> 00:37:41,593 Through strong allegiances and tight teamwork, 294 00:37:41,677 --> 00:37:44,221 the east side friends emerge victorious 295 00:37:44,847 --> 00:37:48,642 {\an8}and win the chance to father the next generation. 296 00:37:48,726 --> 00:37:50,728 {\an8} 297 00:37:52,813 --> 00:37:54,940 Intelligence and collaboration 298 00:37:55,024 --> 00:37:58,986 have enabled dolphins to navigate life in the ocean. 299 00:38:01,405 --> 00:38:03,824 But their home is changing fast. 300 00:38:08,620 --> 00:38:12,291 Even these adaptable animals are struggling to cope. 301 00:38:18,630 --> 00:38:20,716 Our seas are becoming noisier. 302 00:38:22,843 --> 00:38:23,719 Warmer. 303 00:38:25,471 --> 00:38:26,847 And more polluted. 304 00:38:34,313 --> 00:38:35,939 Instead of seaweed, 305 00:38:36,023 --> 00:38:39,151 many dolphins now play with plastic bags. 306 00:38:49,661 --> 00:38:55,334 Swallowing trash kills over 100,000 marine mammals every year. 307 00:38:56,377 --> 00:38:58,629 And chemical contamination 308 00:38:58,712 --> 00:39:01,382 threatens their ability to reproduce. 309 00:39:04,718 --> 00:39:09,348 But industrial-scale fishing is the biggest problem dolphins face… 310 00:39:12,017 --> 00:39:14,436 rapidly depleting their vital food 311 00:39:15,062 --> 00:39:19,233 and drowning hundreds of thousands of them each year. 312 00:39:28,283 --> 00:39:31,412 However, even small changes in our actions 313 00:39:31,495 --> 00:39:33,747 can make a big difference. 314 00:39:47,428 --> 00:39:49,346 When fishermen trawl for shrimp… 315 00:39:52,099 --> 00:39:54,601 other animals are caught in their nets. 316 00:39:57,104 --> 00:40:00,607 But these fishermen now incorporate special openings 317 00:40:00,691 --> 00:40:02,901 so larger animals can escape. 318 00:40:06,196 --> 00:40:09,408 And the local bottlenose have learned to seek them out, 319 00:40:10,868 --> 00:40:14,788 {\an8}using the exit holes to pick out a prize of fish. 320 00:40:31,472 --> 00:40:34,641 Entering these death traps is a risky maneuver. 321 00:40:38,812 --> 00:40:41,732 But these hungry dolphins take their chances. 322 00:40:56,538 --> 00:40:58,332 And the fishermen tolerate them. 323 00:41:01,251 --> 00:41:03,086 There's no loss to their catch. 324 00:41:08,509 --> 00:41:11,261 We still have a lot to learn about dolphins. 325 00:41:12,054 --> 00:41:15,432 And while some species are on the brink of extinction, 326 00:41:17,100 --> 00:41:20,354 new ones are still being found. 327 00:41:26,693 --> 00:41:31,949 It's long been thought there were five species of river dolphin in the world. 328 00:41:32,032 --> 00:41:35,285 Now biologists believe they've discovered a sixth. 329 00:41:37,371 --> 00:41:42,543 Only around 1,000 Araguaian river dolphins are thought to exist. 330 00:41:46,296 --> 00:41:48,048 But every day 331 00:41:48,131 --> 00:41:50,384 in this Brazilian town, 332 00:41:50,467 --> 00:41:52,803 a small number come to hang out. 333 00:41:54,930 --> 00:41:58,475 The local children can hardly wait. 334 00:42:03,730 --> 00:42:08,151 {\an8}It's easy to understand their affinity with these magical animals. 335 00:42:12,739 --> 00:42:17,035 {\an8}Humans and dolphins may inhabit very different worlds… 336 00:42:19,538 --> 00:42:23,041 but there's much in our nature that we share. 337 00:42:30,132 --> 00:42:32,843 A deep connection to be cherished 338 00:42:33,719 --> 00:42:36,513 for generations to come.