1 00:00:00,500 --> 00:00:01,501 ♪ MUSIC ♪ 2 00:00:01,501 --> 00:00:03,503 NARRATOR: Donkeys stranded on a desert island 3 00:00:03,503 --> 00:00:07,674 conquer the arid wilderness. 4 00:00:07,674 --> 00:00:09,476 Pigs in paradise 5 00:00:09,476 --> 00:00:13,680 sunbathe on a Caribbean beach. 6 00:00:13,680 --> 00:00:16,316 And off the east coast of the United States 7 00:00:16,316 --> 00:00:22,789 two herds of horses share one island. 8 00:00:22,789 --> 00:00:24,725 Animals gone wild 9 00:00:24,725 --> 00:00:27,794 must adjust to life on their own. 10 00:00:27,794 --> 00:00:30,430 That means unusual adaptations 11 00:00:30,430 --> 00:00:33,500 and surprising behaviors. 12 00:00:33,500 --> 00:00:35,202 But their very success 13 00:00:35,202 --> 00:00:46,813 could be their downfall. 14 00:00:46,813 --> 00:00:48,548 NARRATOR: Inside the different realms 15 00:00:48,548 --> 00:00:52,185 of the wild kingdom 16 00:00:52,185 --> 00:00:53,854 members of a single species 17 00:00:53,854 --> 00:00:57,658 assemble in droves. 18 00:00:57,658 --> 00:00:58,725 One flock, 19 00:00:58,725 --> 00:01:00,260 herd 20 00:01:00,260 --> 00:01:01,628 or troop 21 00:01:01,628 --> 00:01:04,398 reigns supreme. 22 00:01:04,398 --> 00:01:14,441 These are the world's great 23 00:01:14,441 --> 00:01:24,418 These are the world's great 24 00:01:24,418 --> 00:01:26,486 NARRATOR: The small Dutch island of Bonaire 25 00:01:26,486 --> 00:01:32,826 lies off the northwest coast of Venezuela. 26 00:01:32,826 --> 00:01:36,096 Just over 100 square miles in total area 27 00:01:36,096 --> 00:01:38,765 this tiny island of dry land 28 00:01:38,765 --> 00:01:41,768 and sparse bush, is the adopted home 29 00:01:41,768 --> 00:01:47,741 of one the world's most iconic beasts of burden, 30 00:01:47,741 --> 00:01:51,445 the donkey. 31 00:01:51,445 --> 00:01:53,747 Donkeys have been living wild on Bonaire 32 00:01:53,747 --> 00:01:58,285 for over 500 years. 33 00:01:58,285 --> 00:02:00,053 Most of them have distinctive stripes 34 00:02:00,053 --> 00:02:06,693 that form a cross down their back. 35 00:02:06,693 --> 00:02:09,129 This has led to a long association 36 00:02:09,129 --> 00:02:13,834 between the donkeys and Christianity. 37 00:02:13,834 --> 00:02:16,770 Other than snakes, donkeys are the only animals 38 00:02:16,770 --> 00:02:22,709 that speak in the Bible. 39 00:02:22,709 --> 00:02:25,178 The cross is actually a trait 40 00:02:25,178 --> 00:02:27,814 inherited from the Nubian wild ass, 41 00:02:27,814 --> 00:02:29,750 one of two sub-species from which 42 00:02:29,750 --> 00:02:34,121 all domestic donkeys are descended. 43 00:02:36,223 --> 00:02:38,525 The donkey's ancestors made their home 44 00:02:38,525 --> 00:02:42,729 in the desert land of Northeast Africa, 45 00:02:42,729 --> 00:02:50,404 between Egypt and Somalia. 46 00:02:50,404 --> 00:02:53,573 Then over 5,000 years ago 47 00:02:53,573 --> 00:02:55,342 humans domesticated them, 48 00:02:55,342 --> 00:02:58,111 and brought them across the far reaches of Asia 49 00:02:58,111 --> 00:03:00,647 and into Europe. 50 00:03:00,647 --> 00:03:02,616 In the 16th century, 51 00:03:02,616 --> 00:03:04,217 it was the Spanish conquistadors 52 00:03:04,217 --> 00:03:12,092 that brought donkeys to Bonaire. 53 00:03:12,092 --> 00:03:15,762 For centuries, donkeys were used in Bonaire's salt trade, 54 00:03:15,762 --> 00:03:20,200 alongside enslaved African people. 55 00:03:20,200 --> 00:03:23,670 When slavery was abolished on the island in 1862, 56 00:03:23,670 --> 00:03:27,174 the salt business industrialized. 57 00:03:27,174 --> 00:03:31,078 The donkeys were set free. 58 00:03:31,078 --> 00:03:38,118 Today, they are a reminder of the island's history. 59 00:03:38,118 --> 00:03:41,354 The feral donkeys quickly adapted to Bonaire. 60 00:03:41,354 --> 00:03:47,427 They are naturally suited to desert environments like these. 61 00:03:47,427 --> 00:03:56,336 In the 1950s, their population exceeded 1,200. 62 00:03:56,336 --> 00:04:05,212 There were 10 donkeys for every square mile. 63 00:04:05,212 --> 00:04:07,214 Their diet here consists of grass, 64 00:04:07,214 --> 00:04:12,552 shrubs and desert plants. 65 00:04:12,552 --> 00:04:14,087 The plants also give the donkeys 66 00:04:14,087 --> 00:04:20,060 most of the water they need. 67 00:04:20,060 --> 00:04:22,362 The thick hooves protecting donkey's feet 68 00:04:22,362 --> 00:04:27,601 actually benefit from the rough and rocky ground. 69 00:04:27,601 --> 00:04:30,804 Their hooves are the same material as human fingernails, 70 00:04:30,804 --> 00:04:37,777 and never stop growing. 71 00:04:37,777 --> 00:04:40,680 Trekking across the hard terrain files them down 72 00:04:40,680 --> 00:04:48,588 protecting from painful overgrowth. 73 00:04:48,588 --> 00:04:51,525 To keep cool, the donkeys kick up the desert dust 74 00:04:51,525 --> 00:04:56,530 and cover their bodies. 75 00:04:56,530 --> 00:05:07,073 This insulates them from the hot sun. 76 00:05:07,073 --> 00:05:11,077 Male donkeys are called jacks. 77 00:05:11,077 --> 00:05:13,079 The dominant jack will lead a herd 78 00:05:13,079 --> 00:05:17,050 of around 20 individuals. 79 00:05:17,050 --> 00:05:20,187 The herd includes a harem of up to eight females, 80 00:05:20,187 --> 00:05:22,155 their foals, and often 81 00:05:22,155 --> 00:05:26,793 a few subordinate males too. 82 00:05:26,793 --> 00:05:30,830 These days, the donkey's desert home is changing. 83 00:05:30,830 --> 00:05:34,167 Development on the island and a growing tourism industry 84 00:05:34,167 --> 00:05:37,237 have intensified competition for territory 85 00:05:37,237 --> 00:05:42,075 between jacks. 86 00:05:42,075 --> 00:05:45,345 And, as humans move in on the donkey's turf, 87 00:05:45,345 --> 00:05:56,523 conflicts with their new neighbors are inevitable. 88 00:05:56,523 --> 00:05:57,624 NARRATOR: In the Bahamas, 89 00:05:57,624 --> 00:06:00,327 the Exumas are an island chain 90 00:06:00,327 --> 00:06:04,464 about the length of Long Island, New York. 91 00:06:04,464 --> 00:06:07,334 This is Big Major Cay. 92 00:06:07,334 --> 00:06:10,170 One of the 365 sandy isles 93 00:06:10,170 --> 00:06:13,173 that make up the chain. 94 00:06:13,173 --> 00:06:18,345 It's home to some surprising castaways. 95 00:06:18,345 --> 00:06:21,815 Stranded here, 96 00:06:21,815 --> 00:06:27,487 pigs in paradise. 97 00:06:27,487 --> 00:06:29,789 These are the same species of swine 98 00:06:29,789 --> 00:06:32,826 that can be found on farmer's fields across the globe. 99 00:06:32,826 --> 00:06:39,799 But these ones are feral. 100 00:06:39,799 --> 00:06:45,005 Domesticated pigs are descended from wild boars. 101 00:06:46,740 --> 00:06:49,175 These pigs may live in the Bahamas now, 102 00:06:49,175 --> 00:06:53,813 but their ancestors hail from Asia. 103 00:06:53,813 --> 00:06:56,449 More than ten thousand years ago, 104 00:06:56,449 --> 00:06:58,618 people there started capturing and breeding 105 00:06:58,618 --> 00:07:04,758 wild boars for food. 106 00:07:04,758 --> 00:07:07,360 Today domesticated pigs are found 107 00:07:07,360 --> 00:07:12,265 on every continent except Antarctica. 108 00:07:12,265 --> 00:07:14,267 About one billion domestic pigs 109 00:07:14,267 --> 00:07:16,436 are alive at any given time, 110 00:07:16,436 --> 00:07:18,471 making them among the most numerous 111 00:07:18,471 --> 00:07:22,342 large animals in the world. 112 00:07:22,342 --> 00:07:24,711 But here, domestic pigs have gone wild, 113 00:07:24,711 --> 00:07:30,583 and live feral lives. 114 00:07:30,583 --> 00:07:35,121 Whether it's a nursery rhyme about pigs going to market, 115 00:07:35,121 --> 00:07:37,290 a folk tale featuring three little pigs 116 00:07:37,290 --> 00:07:40,760 hiding from the big bad wolf, 117 00:07:40,760 --> 00:07:42,295 or a classic novel 118 00:07:42,295 --> 00:07:44,698 where a well-meaning spider named Charlotte, 119 00:07:44,698 --> 00:07:47,567 tries to save her barnyard buddy. 120 00:07:47,567 --> 00:07:49,436 Stories about pigs 121 00:07:49,436 --> 00:07:52,138 have been igniting the imagination of children 122 00:07:52,138 --> 00:07:58,445 for centuries. 123 00:07:58,445 --> 00:08:01,581 Big Major Cay is no exception. 124 00:08:01,581 --> 00:08:07,187 The origin of these pigs has become a local legend. 125 00:08:07,187 --> 00:08:09,222 Some speculate that they swam to shore 126 00:08:09,222 --> 00:08:15,362 following a 16th century shipwreck. 127 00:08:15,362 --> 00:08:18,164 The truth is they were actually brought here 128 00:08:18,164 --> 00:08:21,134 as livestock from the Bahamian capital, Nassau 129 00:08:21,134 --> 00:08:27,707 in the 1990s. 130 00:08:27,707 --> 00:08:30,477 At first, there were only five juvenile pigs 131 00:08:30,477 --> 00:08:33,313 and they were fed and fenced in. 132 00:08:33,313 --> 00:08:39,252 But when they grew larger, they escaped. 133 00:08:39,252 --> 00:08:42,789 The pigs survived on the island for seven generations. 134 00:08:42,789 --> 00:08:49,763 Now, the population has grown to over 30. 135 00:08:49,763 --> 00:08:52,198 They may technically be domestic pigs, 136 00:08:52,198 --> 00:08:53,666 but these boars and sows 137 00:08:53,666 --> 00:08:59,706 haven't lost their innate ability to find food. 138 00:08:59,706 --> 00:09:03,176 This behavior is called rooting. 139 00:09:03,176 --> 00:09:04,310 Pigs see the world 140 00:09:04,310 --> 00:09:08,014 through a heightened sense of smell. 141 00:09:08,014 --> 00:09:10,016 Digging with their elongated snouts, 142 00:09:10,016 --> 00:09:11,317 they can sniff out edible roots 143 00:09:11,317 --> 00:09:16,790 as far as three feet underground. 144 00:09:16,790 --> 00:09:19,025 Most of their diet comes from roots, 145 00:09:19,025 --> 00:09:26,166 but they also eat wild cabbage and berries. 146 00:09:26,166 --> 00:09:27,100 They get their water 147 00:09:27,100 --> 00:09:34,641 from the island's three inland springs. 148 00:09:34,641 --> 00:09:41,581 By nature pigs are social, gregarious creatures. 149 00:09:41,581 --> 00:09:46,319 They travel in groups, called sounders. 150 00:09:46,319 --> 00:09:48,755 This one consists of three mature sows, 151 00:09:48,755 --> 00:09:56,229 one boar, and their offspring. 152 00:09:56,229 --> 00:09:58,598 A curious disposition and a broad diet 153 00:09:58,598 --> 00:10:02,302 means pigs can find food in just about any range, 154 00:10:02,302 --> 00:10:07,807 making them one of the world's most adaptable animals. 155 00:10:07,807 --> 00:10:12,645 But there's a downside to their success. 156 00:10:12,645 --> 00:10:15,415 With no predators, the number of pigs here 157 00:10:15,415 --> 00:10:16,816 will continue to grow 158 00:10:16,816 --> 00:10:22,121 until there's not enough food and water for everyone. 159 00:10:22,121 --> 00:10:25,358 Potentially devastating the island's native ecosystem 160 00:10:25,358 --> 00:10:33,833 in the process. 161 00:10:33,833 --> 00:10:36,336 NARRATOR: Assateague is a barrier island 162 00:10:36,336 --> 00:10:37,871 running parallel to the East Coast 163 00:10:37,871 --> 00:10:39,672 of the United States, 164 00:10:39,672 --> 00:10:44,811 from Maryland to Virginia. 165 00:10:44,811 --> 00:10:47,213 It's a narrow strip of sand and sediment 166 00:10:47,213 --> 00:10:54,153 almost 37 miles long. 167 00:10:54,153 --> 00:11:00,493 Another island, with another species gone wild. 168 00:11:00,493 --> 00:11:03,596 Horses. 169 00:11:03,596 --> 00:11:06,099 Assateague's horses have free rein 170 00:11:06,099 --> 00:11:14,173 over the island's open meadows. 171 00:11:14,173 --> 00:11:17,343 Worldwide the population of domestic and feral horses 172 00:11:17,343 --> 00:11:20,580 is estimated to be 58 million, 173 00:11:20,580 --> 00:11:27,153 with over nine million in the United States alone. 174 00:11:27,153 --> 00:11:29,289 There are so many horses in the U.S., 175 00:11:29,289 --> 00:11:31,357 that if they were to form their own state, 176 00:11:31,357 --> 00:11:35,695 it'd be the eleventh most populous in the country. 177 00:11:38,598 --> 00:11:40,667 Prior to their domestication, 178 00:11:40,667 --> 00:11:42,602 horses roamed the open plains 179 00:11:42,602 --> 00:11:45,672 and grasslands of the Eurasian steppes, 180 00:11:45,672 --> 00:11:51,744 from Ukraine to Mongolia. 181 00:11:51,744 --> 00:11:54,213 First domesticated as a food source, 182 00:11:54,213 --> 00:11:56,683 humans eventually realized that tame horses 183 00:11:56,683 --> 00:12:00,720 made great workers. 184 00:12:00,720 --> 00:12:02,755 Over thousands of years, 185 00:12:02,755 --> 00:12:05,725 people brought horses with them across the globe, 186 00:12:05,725 --> 00:12:11,230 just like pigs and donkeys. 187 00:12:11,230 --> 00:12:13,700 Assateague Island's horses have been here 188 00:12:13,700 --> 00:12:20,673 since before the American Revolution. 189 00:12:20,673 --> 00:12:26,713 But how they got here, is a mystery. 190 00:12:26,713 --> 00:12:29,148 Some say that the horses arrived 191 00:12:29,148 --> 00:12:32,285 when two Spanish galleons crashed into the island 192 00:12:32,285 --> 00:12:36,556 during the 1500s. 193 00:12:36,556 --> 00:12:38,825 Others believed that early colonizers 194 00:12:38,825 --> 00:12:40,693 stashed the horses on the island 195 00:12:40,693 --> 00:12:49,769 to avoid paying livestock taxes. 196 00:12:49,769 --> 00:12:51,504 Regardless of how they arrived, 197 00:12:51,504 --> 00:12:56,209 they've been roaming free for over three centuries. 198 00:12:56,209 --> 00:13:09,155 Today 300 horses live on Assateague. 199 00:13:09,155 --> 00:13:12,792 Horses instinctively form herds like this one 200 00:13:12,792 --> 00:13:17,664 to protect one another and act as lookouts. 201 00:13:17,664 --> 00:13:25,371 Feral horse herds are often called bands. 202 00:13:25,371 --> 00:13:27,740 The bands are led by a dominant stallion. 203 00:13:27,740 --> 00:13:29,342 He's the herd's protector 204 00:13:29,342 --> 00:13:32,211 and enforcer of the band's rigid hierarchy, 205 00:13:32,211 --> 00:13:41,220 leading a harem of up to eight mares. 206 00:13:41,220 --> 00:13:42,722 In addition to a dominant stallion, 207 00:13:42,722 --> 00:13:49,228 every band has a lead-mare, like this white horse. 208 00:13:49,228 --> 00:13:57,170 She decides where to graze and when to go find water. 209 00:13:57,170 --> 00:13:59,238 Horses are prey animals. 210 00:13:59,238 --> 00:14:04,110 They grow anxious and flighty when alone, 211 00:14:04,110 --> 00:14:09,115 even here where there are no predators. 212 00:14:09,115 --> 00:14:11,484 The company and hierarchy of the band 213 00:14:11,484 --> 00:14:18,124 keep everyone feeling secure. 214 00:14:18,124 --> 00:14:19,759 With winter on its way, 215 00:14:19,759 --> 00:14:22,495 this horse has begun shedding dead hair 216 00:14:22,495 --> 00:14:27,166 and growing in a thicker coat. 217 00:14:27,166 --> 00:14:28,634 The horse's pituitary gland 218 00:14:28,634 --> 00:14:31,204 recognizes the shift in daylight hours, 219 00:14:31,204 --> 00:14:32,138 and produces a hormone 220 00:14:32,138 --> 00:14:38,745 that triggers the increased hair growth. 221 00:14:38,745 --> 00:14:45,351 It's an itchy process for the horse. 222 00:14:45,351 --> 00:14:51,457 Horses need to keep their coat well groomed all year. 223 00:14:51,457 --> 00:14:53,626 It regulates body temperature 224 00:14:53,626 --> 00:14:57,130 and protects against the elements. 225 00:14:57,130 --> 00:15:00,066 Horses also produce pheromones 226 00:15:00,066 --> 00:15:02,635 that make it possible to identify other herd members 227 00:15:02,635 --> 00:15:12,278 from as far as 400 feet away. 228 00:15:12,278 --> 00:15:14,080 Of course, there's always an itch 229 00:15:14,080 --> 00:15:21,554 that you just can't reach without a little help. 230 00:15:21,554 --> 00:15:23,689 When animals clean each other 231 00:15:23,689 --> 00:15:30,096 its called "allo-grooming." 232 00:15:30,096 --> 00:15:33,332 It's a sign of an intense bond between horses. 233 00:15:33,332 --> 00:15:35,635 The more horses an individual grooms, 234 00:15:35,635 --> 00:15:42,575 the higher her social status is within the herd. 235 00:15:42,575 --> 00:15:44,644 Scientists have even found that mares, 236 00:15:44,644 --> 00:15:46,579 who are the most gregarious groomers, 237 00:15:46,579 --> 00:15:56,856 also produce the most offspring. 238 00:15:56,856 --> 00:16:05,598 Horses spend between 15 and 17 hours a day grazing. 239 00:16:05,598 --> 00:16:09,035 Horses here eat the grasses that grow in the salt-marsh 240 00:16:09,035 --> 00:16:13,739 or on the beach. 241 00:16:13,739 --> 00:16:16,108 This diet is high in salt content, 242 00:16:16,108 --> 00:16:18,344 so the horses drink twice as much water 243 00:16:18,344 --> 00:16:23,816 as other wild horses. 244 00:16:23,816 --> 00:16:35,161 All that water makes them bloated. 245 00:16:35,161 --> 00:16:37,597 The grasses are also low in nutrients, 246 00:16:37,597 --> 00:16:40,466 so the Assateague horses are shorter and stockier 247 00:16:40,466 --> 00:16:52,378 than other breeds. 248 00:16:52,378 --> 00:17:00,286 Adult horses eat 21,000 calories each day. 249 00:17:00,286 --> 00:17:02,788 Grazing the grass and trampling the field 250 00:17:02,788 --> 00:17:06,626 takes an enormous toll on the island, 251 00:17:06,626 --> 00:17:12,665 and increases erosion. 252 00:17:12,665 --> 00:17:16,569 With no natural predators to control the population, 253 00:17:16,569 --> 00:17:19,105 these horses could eat themselves 254 00:17:19,105 --> 00:17:28,648 out of house and home. 255 00:17:28,648 --> 00:17:30,082 NARRATOR: In the 1950s, 256 00:17:30,082 --> 00:17:36,589 there were 5500 people living on Bonaire. 257 00:17:36,589 --> 00:17:39,525 At the time, that meant that for every five people 258 00:17:39,525 --> 00:17:46,098 on the island, there was one donkey. 259 00:17:46,098 --> 00:17:47,833 But as the world changes around them, 260 00:17:47,833 --> 00:17:55,141 the donkeys are starting to disappear. 261 00:17:55,141 --> 00:17:57,643 These days it's tourism, not salt, 262 00:17:57,643 --> 00:18:03,082 that drives Bonaire's economy. 263 00:18:03,082 --> 00:18:05,584 70,000 people visit annually, 264 00:18:05,584 --> 00:18:08,354 most of them coming to dive the clear blue water 265 00:18:08,354 --> 00:18:14,694 and explore the coral reef that surrounds the island. 266 00:18:14,694 --> 00:18:17,063 16,000 human residents 267 00:18:17,063 --> 00:18:23,235 now also call the island home. 268 00:18:23,235 --> 00:18:25,805 Development has encroached on the donkey's former range, 269 00:18:25,805 --> 00:18:28,774 meaning there's less area to graze 270 00:18:28,774 --> 00:18:35,381 and less food to go around. 271 00:18:35,381 --> 00:18:37,049 Many also believe, 272 00:18:37,049 --> 00:18:39,652 the donkeys are throwing the ecosystem out of balance 273 00:18:39,652 --> 00:18:44,090 killing plants and, like the Assateague horses, 274 00:18:44,090 --> 00:18:55,701 eroding the island with their non-stop grazing. 275 00:18:55,701 --> 00:18:58,070 The donkey's brave new world 276 00:18:58,070 --> 00:19:02,008 is full of unknown threats, 277 00:19:02,008 --> 00:19:04,710 And their ancient instincts never prepared them 278 00:19:04,710 --> 00:19:19,325 for dangers like these. 279 00:19:19,325 --> 00:19:23,229 Unlike horses, who instinctively flee nearby threats, 280 00:19:23,229 --> 00:19:27,166 these frightened donkeys freeze in the face of danger, 281 00:19:27,166 --> 00:19:36,809 stopping to investigate threats. 282 00:19:36,809 --> 00:19:39,378 It's an impractical defense 283 00:19:39,378 --> 00:19:44,650 when your range extends across roadways. 284 00:19:44,650 --> 00:19:52,124 Donkeys stay close to the road for a reason. 285 00:19:52,124 --> 00:19:58,397 It's quite resourceful and efficient for grazing. 286 00:19:58,397 --> 00:20:00,266 The asphalt repels water, 287 00:20:00,266 --> 00:20:02,468 which means that during the rainy season, 288 00:20:02,468 --> 00:20:04,270 runoff from the road 289 00:20:04,270 --> 00:20:07,173 spills over onto the curbside, 290 00:20:07,173 --> 00:20:13,512 cultivating some of the island's most luscious greens. 291 00:20:13,512 --> 00:20:16,348 In recent years, up to 60 donkeys annually 292 00:20:16,348 --> 00:20:23,489 have been killed in motor vehicle accidents. 293 00:20:23,489 --> 00:20:25,357 Even though their numbers are declining, 294 00:20:25,357 --> 00:20:27,326 there are still too many donkeys 295 00:20:27,326 --> 00:20:32,231 and not enough space. 296 00:20:32,231 --> 00:20:34,667 So measures have been put in place to control 297 00:20:34,667 --> 00:20:42,374 Bonaire's remaining population of wild donkeys. 298 00:20:42,374 --> 00:20:44,143 Jacks have been gelded, 299 00:20:44,143 --> 00:20:57,256 and then released back into the wild. 300 00:20:57,256 --> 00:21:00,826 Meanwhile mares are being relocated to a protected area, 301 00:21:00,826 --> 00:21:08,601 safe from the island's development. 302 00:21:08,601 --> 00:21:11,270 Limiting the number of free roaming donkeys on the island 303 00:21:11,270 --> 00:21:13,172 means fewer car accidents, 304 00:21:13,172 --> 00:21:19,278 and more space for the donkeys to graze. 305 00:21:19,278 --> 00:21:22,114 But population control may just be the straw 306 00:21:22,114 --> 00:21:26,785 that finally breaks the donkey's back. 307 00:21:26,785 --> 00:21:29,188 It might mean the long history of the donkeys' 308 00:21:29,188 --> 00:21:31,157 wild life on Bonaire 309 00:21:31,157 --> 00:21:38,597 could be coming to an end. 310 00:21:38,597 --> 00:21:41,133 NARRATOR: The wild pigs' colonization 311 00:21:41,133 --> 00:21:42,768 of the Bahamas' Big Major Cay 312 00:21:42,768 --> 00:21:44,770 has been so successful 313 00:21:44,770 --> 00:21:47,339 that the locals now refer to this spot 314 00:21:47,339 --> 00:21:55,481 as Pig Beach. 315 00:21:55,481 --> 00:21:58,117 To avoid the hot sun, the island pigs 316 00:21:58,117 --> 00:22:00,085 spend the hottest hours of the day 317 00:22:00,085 --> 00:22:04,523 in the shade. 318 00:22:04,523 --> 00:22:06,825 They save their foraging for the early morning 319 00:22:06,825 --> 00:22:12,531 and late afternoon. 320 00:22:12,531 --> 00:22:17,236 Pigs don't have sweat glands to help them keep cool. 321 00:22:17,236 --> 00:22:18,504 They're susceptible to heat exhaustion, 322 00:22:18,504 --> 00:22:25,244 sunburns and even skin cancer. 323 00:22:25,244 --> 00:22:26,712 Wallowing in sand, 324 00:22:26,712 --> 00:22:28,614 while not as effective as a mud bath, 325 00:22:28,614 --> 00:22:30,516 cools them, and also helps the pigs 326 00:22:30,516 --> 00:22:39,258 by shielding them from harmful UV rays. 327 00:22:39,258 --> 00:22:43,495 And when things get really hot, 328 00:22:43,495 --> 00:22:52,705 these pigs have another trick up their snouts. 329 00:22:52,705 --> 00:23:00,479 Out on the ocean, a commotion sounds. 330 00:23:00,479 --> 00:23:04,183 The pigs storm the sea. 331 00:23:04,183 --> 00:23:10,356 And then, an even more curious behavior, 332 00:23:10,356 --> 00:23:14,827 they piggy paddle out to the waiting boats. 333 00:23:14,827 --> 00:23:19,265 They weigh between 100 and 200 pounds each, 334 00:23:19,265 --> 00:23:23,836 and they're not exactly hydrodynamic. 335 00:23:23,836 --> 00:23:26,505 But what these pigs lack in speed 336 00:23:26,505 --> 00:23:30,743 they make up for in determination. 337 00:23:30,743 --> 00:23:33,379 In the last 10 years, the legend of Pig Beach 338 00:23:33,379 --> 00:23:38,150 has spread far beyond the Bahamas. 339 00:23:38,150 --> 00:23:40,286 They've become the biggest single attraction 340 00:23:40,286 --> 00:23:44,757 in the Exuma Cays. 341 00:23:44,757 --> 00:23:47,693 The sight, sounds and smells of boats and humans 342 00:23:47,693 --> 00:23:49,595 draw the pigs out of the bush, 343 00:23:49,595 --> 00:23:55,501 and into the water. 344 00:23:55,501 --> 00:23:58,437 This isn't the first time stories of swimming pigs 345 00:23:58,437 --> 00:24:04,576 have amazed humans. 346 00:24:04,576 --> 00:24:06,645 During a World War I naval battle, 347 00:24:06,645 --> 00:24:09,281 an attacking British vessel rescued a pig 348 00:24:09,281 --> 00:24:15,054 swimming away from a sinking German ship. 349 00:24:15,054 --> 00:24:17,756 He was nicknamed Tirpitz, and became the official mascot 350 00:24:17,756 --> 00:24:23,429 of the HMS Glasgow. 351 00:24:23,429 --> 00:24:27,099 In 1946, 200 pigs were brought to the Marshall Islands 352 00:24:27,099 --> 00:24:29,468 to test the effect of nuclear fallout 353 00:24:29,468 --> 00:24:35,074 from an atomic bomb detonation. 354 00:24:35,074 --> 00:24:37,843 After the explosion, they found Pig Number 311 355 00:24:37,843 --> 00:24:44,717 swimming safe and sound in the Pacific Ocean. 356 00:24:44,717 --> 00:24:47,453 She lived out her remaining days at Smithsonian's 357 00:24:47,453 --> 00:24:56,528 National Zoological Park in Washington, D.C. 358 00:24:56,528 --> 00:24:59,431 Swimming is actually instinctual in pigs, 359 00:24:59,431 --> 00:25:02,634 and can be traced back to their ancient ancestors. 360 00:25:02,634 --> 00:25:08,307 Wild boars are exceptional swimmers. 361 00:25:08,307 --> 00:25:12,111 In 2013, a wild boar swam seven miles 362 00:25:12,111 --> 00:25:13,779 into the English Channel, 363 00:25:13,779 --> 00:25:19,718 and was found on an island off the coast of France. 364 00:25:19,718 --> 00:25:22,254 So if pigs have always been able to swim, 365 00:25:22,254 --> 00:25:25,724 why is it such a rare sight? 366 00:25:25,724 --> 00:25:27,092 For the most part, 367 00:25:27,092 --> 00:25:33,365 domestic pigs just have no reason to swim. 368 00:25:33,365 --> 00:25:35,367 So what makes Big Major Cay's pigs 369 00:25:35,367 --> 00:25:38,704 take to the sea? 370 00:25:38,704 --> 00:25:40,372 Food naturally! 371 00:25:40,372 --> 00:25:47,379 From the same humans who come to see them swim. 372 00:25:47,379 --> 00:25:49,681 Widely considered amongst the smartest animals 373 00:25:49,681 --> 00:25:52,518 on the planet, pigs have similar brainpower 374 00:25:52,518 --> 00:26:01,193 as elephants, dolphins and chimpanzees. 375 00:26:01,193 --> 00:26:03,429 Pigs have excellent long-term memories 376 00:26:03,429 --> 00:26:10,736 and exhibit extraordinary problem-solving skills. 377 00:26:10,736 --> 00:26:12,404 Both qualities help them exploit 378 00:26:12,404 --> 00:26:24,316 what's become a dependable supplementary food source. 379 00:26:24,316 --> 00:26:26,285 Locals were the first to discover 380 00:26:26,285 --> 00:26:31,523 Big Major Cay's swimming pigs. 381 00:26:31,523 --> 00:26:33,792 But in the age of social media, 382 00:26:33,792 --> 00:26:36,495 word spreads quickly. 383 00:26:36,495 --> 00:26:39,164 By the mid-2000s, photos of the pigs 384 00:26:39,164 --> 00:26:43,702 began popping up online. 385 00:26:43,702 --> 00:26:49,675 Before long, the pigs went viral. 386 00:26:49,675 --> 00:26:52,177 They've made international headlines, 387 00:26:52,177 --> 00:26:53,645 partied with pop stars, 388 00:26:53,645 --> 00:26:55,547 been photographed with swimsuit models, 389 00:26:55,547 --> 00:27:04,590 and even appeared on reality television shows. 390 00:27:04,590 --> 00:27:07,259 Hashtag pigs in paradise? 391 00:27:07,259 --> 00:27:11,430 Not so fast. 392 00:27:11,430 --> 00:27:13,265 The daily visits and supplemental feeding 393 00:27:13,265 --> 00:27:14,600 are beginning to blur the line 394 00:27:14,600 --> 00:27:22,274 between wild and domesticated once again. 395 00:27:22,274 --> 00:27:24,710 Although the pigs here are being fed, 396 00:27:24,710 --> 00:27:26,678 there's no one directly responsible 397 00:27:26,678 --> 00:27:37,556 for their well being. 398 00:27:37,556 --> 00:27:44,763 If left unchecked, feral pig populations grow rapidly. 399 00:27:44,763 --> 00:27:51,136 One sow can birth over 20 piglets annually. 400 00:27:51,136 --> 00:27:53,305 The number of feral pigs in the United States 401 00:27:53,305 --> 00:27:55,641 has tripled in the last 25 years, 402 00:27:55,641 --> 00:28:01,647 from two million to six million pigs. 403 00:28:01,647 --> 00:28:05,150 An island like this one could quickly become overrun, 404 00:28:05,150 --> 00:28:11,089 devastating the local flora and fauna. 405 00:28:11,089 --> 00:28:13,492 In the past, population control for swine 406 00:28:13,492 --> 00:28:19,531 meant the slaughterhouse. 407 00:28:19,531 --> 00:28:25,070 Nobody seems keen to take these little piggies to market. 408 00:28:25,070 --> 00:28:26,071 But If left alone, 409 00:28:26,071 --> 00:28:28,807 the number of pigs living in this hog heaven 410 00:28:28,807 --> 00:28:37,616 could go hog wild. 411 00:28:37,616 --> 00:28:40,485 NARRATOR: The sand that makes up Assateague Island's beaches 412 00:28:40,485 --> 00:28:42,254 comes from the ancient eroded rock 413 00:28:42,254 --> 00:28:47,059 of the nearby Appalachian Mountains. 414 00:28:47,059 --> 00:28:49,528 Waves pounding against the shore, move the sand, 415 00:28:49,528 --> 00:28:51,263 and keep this barrier island 416 00:28:51,263 --> 00:28:56,134 in a state of constant flux. 417 00:28:56,134 --> 00:28:59,104 But man-made barriers also shape life on this island, 418 00:28:59,104 --> 00:29:03,041 for both people, and horses. 419 00:29:07,145 --> 00:29:09,481 A state border runs across the island, 420 00:29:09,481 --> 00:29:14,353 separating it into two parks. 421 00:29:14,353 --> 00:29:16,021 The northern section of the island 422 00:29:16,021 --> 00:29:16,888 is Maryland's 423 00:29:16,888 --> 00:29:21,360 Assateague Island National Seashore. 424 00:29:21,360 --> 00:29:23,295 The southern part is in Virginia, 425 00:29:23,295 --> 00:29:24,329 where the horses live 426 00:29:24,329 --> 00:29:33,138 on the Chincoteague National Wildlife Refuge. 427 00:29:33,138 --> 00:29:34,806 A fence separates the two parks 428 00:29:34,806 --> 00:29:36,575 and divides the island's horses 429 00:29:36,575 --> 00:29:42,481 into two distinct herds. 430 00:29:42,481 --> 00:29:47,519 This is one of the Maryland horses. 431 00:29:47,519 --> 00:29:48,820 Now in his fourth year, 432 00:29:48,820 --> 00:29:53,158 he's just beginning to reach sexual maturity. 433 00:29:53,158 --> 00:29:57,129 He's on his own. 434 00:29:57,129 --> 00:29:59,665 The leader of his band, probably his own father, 435 00:29:59,665 --> 00:30:01,733 chased him away when he got old enough 436 00:30:01,733 --> 00:30:07,072 to become a threat to the stallion's dominance. 437 00:30:07,072 --> 00:30:09,574 For horses, this is an instinctual prevention 438 00:30:09,574 --> 00:30:13,345 against inbreeding. 439 00:30:13,345 --> 00:30:15,080 Stallions form their own band 440 00:30:15,080 --> 00:30:20,552 by drawing in females that have also been cast out, 441 00:30:20,552 --> 00:30:21,820 Or by attracting a mare 442 00:30:21,820 --> 00:30:27,159 that's left her band to give birth. 443 00:30:27,159 --> 00:30:29,861 The Assateague Island horses are one of the few 444 00:30:29,861 --> 00:30:37,669 wild roaming herds in the United States. 445 00:30:37,669 --> 00:30:40,672 They're the subjects of ongoing studies by scientists 446 00:30:40,672 --> 00:30:42,207 striving to understand 447 00:30:42,207 --> 00:30:48,814 the secrets of wild horse herds. 448 00:30:48,814 --> 00:30:50,582 They've found that individual horses 449 00:30:50,582 --> 00:30:52,851 form close bonds with each other, 450 00:30:52,851 --> 00:30:55,754 but these relationships are so prone to fall-outs, 451 00:30:55,754 --> 00:30:58,290 that researchers have compared life in the herd 452 00:30:58,290 --> 00:31:05,097 to a soap opera. 453 00:31:05,097 --> 00:31:07,132 The horse's reign on Assateague Island 454 00:31:07,132 --> 00:31:09,534 faces a similar set of threats 455 00:31:09,534 --> 00:31:16,108 as the donkey's empire on Bonaire. 456 00:31:16,108 --> 00:31:17,843 The horses are drawn to the rich grasses 457 00:31:17,843 --> 00:31:20,145 on the side of the road; 458 00:31:20,145 --> 00:31:24,349 humans are drawn to the majestic horses. 459 00:31:24,349 --> 00:31:33,125 It's a dangerous and potentially deadly combination. 460 00:31:33,125 --> 00:31:34,292 Since 1982, 461 00:31:34,292 --> 00:31:43,135 traffic accidents have killed 29 horses on the island. 462 00:31:43,135 --> 00:31:44,836 But the horses themselves 463 00:31:44,836 --> 00:31:50,842 may be their own worst enemy. 464 00:31:50,842 --> 00:31:52,010 By pulling up the grass, 465 00:31:52,010 --> 00:31:58,817 the hungry horses are weakening the island's foundation. 466 00:31:58,817 --> 00:32:04,089 This salt marsh is regularly flooded by the tides. 467 00:32:04,089 --> 00:32:06,258 Assateague is a barrier island 468 00:32:06,258 --> 00:32:19,104 and, like all barrier islands, it's made from sand. 469 00:32:19,104 --> 00:32:21,273 The grass is the glue that keeps the island 470 00:32:21,273 --> 00:32:27,646 from washing away. 471 00:32:27,646 --> 00:32:30,348 When this area was made a National Park in the 1960s, 472 00:32:30,348 --> 00:32:32,450 there were only 28 horses 473 00:32:32,450 --> 00:32:40,425 living on the Maryland side of the island. 474 00:32:40,425 --> 00:32:42,460 A nor'easter had decimated their numbers, 475 00:32:42,460 --> 00:32:49,868 and the park sought to protect the small herd. 476 00:32:49,868 --> 00:32:54,739 By 1997, the herd's numbers had risen to 165, 477 00:32:54,739 --> 00:32:58,710 and the park faced the opposite problem. 478 00:32:58,710 --> 00:33:05,183 The horse population was too high. 479 00:33:05,183 --> 00:33:07,185 To protect the horses and their home, 480 00:33:07,185 --> 00:33:09,221 the United States National Park Service 481 00:33:09,221 --> 00:33:15,694 put in place a plan to control the population. 482 00:33:15,694 --> 00:33:17,062 Most of the female horses 483 00:33:17,062 --> 00:33:18,830 on the Maryland side of the island 484 00:33:18,830 --> 00:33:25,337 are now on birth control. 485 00:33:25,337 --> 00:33:27,606 Mares who have given birth at least once 486 00:33:27,606 --> 00:33:29,341 are shot with a dart gun 487 00:33:29,341 --> 00:33:38,350 containing a state-of-the-art equine contraceptive. 488 00:33:38,350 --> 00:33:40,552 For the first few years of the program, 489 00:33:40,552 --> 00:33:45,690 the population continued to grow. 490 00:33:45,690 --> 00:33:47,325 But officials were patient 491 00:33:47,325 --> 00:33:50,595 and in 2014 the Maryland horse population 492 00:33:50,595 --> 00:33:53,498 dropped to a sustainable 100 horses, 493 00:33:53,498 --> 00:34:01,273 with no cull or relocation necessary. 494 00:34:01,273 --> 00:34:04,042 The female horses that receive the contraceptive 495 00:34:04,042 --> 00:34:06,678 even live longer because they're spared the stress 496 00:34:06,678 --> 00:34:11,182 of pregnancy and nursing. 497 00:34:11,182 --> 00:34:20,759 The future of the Maryland horses has been secured. 498 00:34:20,759 --> 00:34:22,494 On the Virginia side of the island, 499 00:34:22,494 --> 00:34:26,131 the horses' appetite poses the same threat 500 00:34:26,131 --> 00:34:28,700 to the Island's foundation. 501 00:34:28,700 --> 00:34:30,235 But officials there 502 00:34:30,235 --> 00:34:32,203 are trying a different solution 503 00:34:32,203 --> 00:34:43,114 to manage the population. 504 00:34:43,114 --> 00:34:45,583 NARRATOR: Worldwide, 95% of donkeys 505 00:34:45,583 --> 00:34:50,755 are still domesticated workers. 506 00:34:50,755 --> 00:34:53,358 In places like Latin America, the Middle East, 507 00:34:53,358 --> 00:34:56,094 India and Sub-Saharan Africa, 508 00:34:56,094 --> 00:35:01,633 they remain a valuable beast of burden. 509 00:35:01,633 --> 00:35:04,269 There are an estimated 44 million donkeys 510 00:35:04,269 --> 00:35:12,310 around the globe, and their numbers are growing. 511 00:35:12,310 --> 00:35:15,547 In industrialized countries it's a different story; 512 00:35:15,547 --> 00:35:21,252 donkeys are in steep decline. 513 00:35:21,252 --> 00:35:28,693 Affordable cars and trucks mean donkeys get left behind. 514 00:35:28,693 --> 00:35:32,397 Donkey Sanctuary Bonaire exists to ensure the future 515 00:35:32,397 --> 00:35:43,408 of the next generation of the island's donkeys. 516 00:35:43,408 --> 00:35:46,444 It was established in 1993 to help care for 517 00:35:46,444 --> 00:35:57,722 the island's sick and injured donkeys. 518 00:35:57,722 --> 00:36:00,725 Displaced by development, and killed by cars, 519 00:36:00,725 --> 00:36:04,162 before the sanctuary, the donkeys' island empire 520 00:36:04,162 --> 00:36:12,037 was on the road to extinction. 521 00:36:12,037 --> 00:36:14,572 The donkeys here are fed three times a day, 522 00:36:14,572 --> 00:36:17,042 a diet of horse pellets, vegetables 523 00:36:17,042 --> 00:36:28,186 and as much hay as they can eat. 524 00:36:28,186 --> 00:36:30,522 These days its far safer for Bonaire's donkeys 525 00:36:30,522 --> 00:36:32,357 to live in the sanctuary 526 00:36:32,357 --> 00:36:40,765 than it is to try and survive in the wild. 527 00:36:40,765 --> 00:36:42,667 This foal was brought to the sanctuary 528 00:36:42,667 --> 00:36:46,738 when she was just two weeks old. 529 00:36:46,738 --> 00:36:48,273 She was hit by a car 530 00:36:48,273 --> 00:36:52,710 and was found with a broken leg. 531 00:36:52,710 --> 00:36:54,846 Without Donkey Sanctuary Bonaire 532 00:36:54,846 --> 00:37:02,353 she would have died. 533 00:37:02,353 --> 00:37:09,627 Here on-site veterinarians provide regular check-ups. 534 00:37:09,627 --> 00:37:16,101 The foal's two months old now, and still healing. 535 00:37:16,101 --> 00:37:18,069 They line her legs with wooden stints 536 00:37:18,069 --> 00:37:25,276 to keep the bone straight. 537 00:37:25,276 --> 00:37:28,613 Donkeys' bones grow until they're 3 years old. 538 00:37:28,613 --> 00:37:31,583 This is a critical time. If her bone doesn't set right, 539 00:37:31,583 --> 00:37:34,085 she'll face a life of constant pain, 540 00:37:34,085 --> 00:37:43,595 and will need to be euthanized. 541 00:37:43,595 --> 00:37:46,531 But so far the young foal is doing well, 542 00:37:46,531 --> 00:37:48,299 and if she continues to recover, 543 00:37:48,299 --> 00:38:02,413 she could live to be 40. 544 00:38:02,413 --> 00:38:05,316 Today close to half of the island's donkeys 545 00:38:05,316 --> 00:38:15,460 live in the safety of the sanctuary. 546 00:38:15,460 --> 00:38:17,095 That means 600 donkeys 547 00:38:17,095 --> 00:38:26,104 don't have to worry about car accidents. 548 00:38:26,104 --> 00:38:27,805 The jacks are more aggressive, 549 00:38:27,805 --> 00:38:33,144 so they still roam free on the outside. 550 00:38:33,144 --> 00:38:35,113 Most are tagged, chipped and gelded 551 00:38:35,113 --> 00:38:40,451 to limit population growth. 552 00:38:40,451 --> 00:38:42,620 Meanwhile, the island is still looking for ways 553 00:38:42,620 --> 00:38:47,225 to make the wild safer for donkeys. 554 00:38:47,225 --> 00:38:48,760 Like these street signs 555 00:38:48,760 --> 00:38:51,062 that have been placed across the island, 556 00:38:51,062 --> 00:38:59,671 warning motorists to look out for crossing donkeys. 557 00:38:59,671 --> 00:39:02,307 The next step is a scientific study to determine 558 00:39:02,307 --> 00:39:09,380 the number of donkeys the island can support. 559 00:39:09,380 --> 00:39:12,083 When the carrying capacity of the island is determined, 560 00:39:12,083 --> 00:39:14,619 and measures are put in place to keep wild donkeys 561 00:39:14,619 --> 00:39:17,288 away from human development, 562 00:39:17,288 --> 00:39:24,429 Bonaire will be safe for donkeys once again. 563 00:39:24,429 --> 00:39:27,465 Until then, the Sanctuary will continue providing 564 00:39:27,465 --> 00:39:32,537 the highest quality of life possible. 565 00:39:32,537 --> 00:39:35,440 That includes plans to deepen the island's gene pool 566 00:39:35,440 --> 00:39:39,577 by artificially inseminating mares. 567 00:39:39,577 --> 00:39:44,182 So when the time comes for the donkeys to live free again, 568 00:39:44,182 --> 00:39:46,317 Bonaire's donkeys will have 569 00:39:46,317 --> 00:39:49,821 the best possible chance of survival. 570 00:39:49,821 --> 00:39:52,457 The donkey's long reigning empire 571 00:39:52,457 --> 00:40:02,500 may soon be ready to rise again. 572 00:40:02,500 --> 00:40:04,502 NARRATOR: On a second sandy and deserted island 573 00:40:04,502 --> 00:40:05,737 in the Bahamas, 574 00:40:05,737 --> 00:40:09,073 the burgeoning empire of Bahamian pigs 575 00:40:09,073 --> 00:40:11,743 is growing. 576 00:40:11,743 --> 00:40:14,812 These pigs were born on Pig Beach, 577 00:40:14,812 --> 00:40:20,852 about 55 miles away from Big Major Cay. 578 00:40:20,852 --> 00:40:22,487 They were relocated here 579 00:40:22,487 --> 00:40:25,123 because its closer to the Exuma's capital, 580 00:40:25,123 --> 00:40:32,697 and therefore more accessible to tourists. 581 00:40:32,697 --> 00:40:35,633 This sounder is comprised of three separate litters, 582 00:40:35,633 --> 00:40:40,838 each with about 4-7 piglets. 583 00:40:40,838 --> 00:40:43,841 Like all piglets, they were born highly developed; 584 00:40:43,841 --> 00:40:46,244 they could see and hear at birth, 585 00:40:46,244 --> 00:40:51,549 and walk within minutes. 586 00:40:51,549 --> 00:40:53,785 The youngest pigs are just six weeks old, 587 00:40:53,785 --> 00:41:01,426 but a life-long "pecking order" already exists among siblings. 588 00:41:01,426 --> 00:41:03,828 It was established the day they were born, 589 00:41:03,828 --> 00:41:10,768 as the piglets competed to suckle from teats. 590 00:41:10,768 --> 00:41:13,438 The piglets will nurse for up to five months, 591 00:41:13,438 --> 00:41:15,273 but even after they've weaned 592 00:41:15,273 --> 00:41:25,817 they'll remain close to their mother and siblings. 593 00:41:25,817 --> 00:41:28,252 Unlike the pigs on Big Major Cay, 594 00:41:28,252 --> 00:41:38,863 these pigs can't survive without human help. 595 00:41:38,863 --> 00:41:41,733 Because there's no freshwater spring on this island, 596 00:41:41,733 --> 00:41:50,375 their drinking water is shipped here daily. 597 00:41:50,375 --> 00:41:57,448 The pigs here have been domesticated once again. 598 00:41:57,448 --> 00:42:01,786 Their new fence is the Caribbean sea. 599 00:42:01,786 --> 00:42:08,393 It's an odd combination of agriculture and tourism. 600 00:42:08,393 --> 00:42:10,395 The spread of this pig empire 601 00:42:10,395 --> 00:42:12,397 could spell disaster for both pigs 602 00:42:12,397 --> 00:42:18,836 and their adopted lands. 603 00:42:18,836 --> 00:42:21,672 Across the Bahamas other introduced species 604 00:42:21,672 --> 00:42:28,446 like cats and mice, have decimated island ecosystems. 605 00:42:28,446 --> 00:42:30,681 Left free the highly adaptable pigs 606 00:42:30,681 --> 00:42:33,551 could eventually outcompete native species, 607 00:42:33,551 --> 00:42:41,859 and wipeout local plant life in the process. 608 00:42:41,859 --> 00:42:44,562 The unregulated nature of this bizarre phenomenon 609 00:42:44,562 --> 00:42:46,197 means there's currently 610 00:42:46,197 --> 00:42:51,402 no population management plan. 611 00:42:51,402 --> 00:42:54,305 But for the pigs, life in the Bahamas 612 00:42:54,305 --> 00:42:57,408 beats life on the farm. 613 00:42:57,408 --> 00:43:03,214 Most of those pigs don't make it to their first birthday. 614 00:43:03,214 --> 00:43:05,750 As long as they have food, shelter and water they need, 615 00:43:05,750 --> 00:43:17,829 these pigs could live for another 20 years. 616 00:43:17,829 --> 00:43:20,731 NARRATOR: The Chincoteague National Wildlife Refuge 617 00:43:20,731 --> 00:43:22,733 in Virginia, is on the southern side 618 00:43:22,733 --> 00:43:33,277 of Assateague Island. 619 00:43:33,277 --> 00:43:35,847 Though these horses are left to roam free, 620 00:43:35,847 --> 00:43:38,216 each one is branded with the year of their birth 621 00:43:38,216 --> 00:43:44,722 so the herd's numbers can be monitored over time. 622 00:43:44,722 --> 00:43:46,824 There are a few differences between the northern 623 00:43:46,824 --> 00:43:50,528 and southern Assateague horses. 624 00:43:50,528 --> 00:43:54,765 One difference is their name. 625 00:43:54,765 --> 00:44:00,304 Down here people call them Chincoteague ponies. 626 00:44:00,304 --> 00:44:05,243 Genetically a horse and a pony are the same. 627 00:44:05,243 --> 00:44:08,613 The difference is in the height. 628 00:44:08,613 --> 00:44:11,215 Horses are taller; 629 00:44:11,215 --> 00:44:15,386 island life has made these short and stocky over time, 630 00:44:15,386 --> 00:44:19,056 so by equestrian standards, the Assateague horses 631 00:44:19,056 --> 00:44:23,394 are, in fact, also ponies. 632 00:44:23,394 --> 00:44:26,430 The Chincoteague ponies' relentless grazing 633 00:44:26,430 --> 00:44:28,699 poses the same threat to the island 634 00:44:28,699 --> 00:44:34,305 as their northern cousins. 635 00:44:34,305 --> 00:44:36,507 When unmanaged, feral horse populations 636 00:44:36,507 --> 00:44:43,514 can double every four years. 637 00:44:43,514 --> 00:44:46,551 But even though 70 new foals are born each year, 638 00:44:46,551 --> 00:44:48,419 the effect on the ecosystem here 639 00:44:48,419 --> 00:44:54,225 hasn't been as severe. 640 00:44:54,225 --> 00:44:55,760 To prevent overpopulation 641 00:44:55,760 --> 00:45:02,567 this herd has been managed for nearly a century. 642 00:45:02,567 --> 00:45:04,035 But it's done differently 643 00:45:04,035 --> 00:45:08,105 than it is for their northern cousins. 644 00:45:08,105 --> 00:45:10,141 Each spring, once foals are weaned, 645 00:45:10,141 --> 00:45:12,076 they're rounded up and auctioned off, 646 00:45:12,076 --> 00:45:19,283 sent to new homes off the island. 647 00:45:19,283 --> 00:45:21,752 Today there are over a thousand Chincoteague ponies 648 00:45:21,752 --> 00:45:25,189 living on the mainland. 649 00:45:25,189 --> 00:45:28,259 The breed is highly valued for their calm demeanor 650 00:45:28,259 --> 00:45:33,631 and a hardy nature. 651 00:45:33,631 --> 00:45:36,100 Every year, a few foals are kept back 652 00:45:36,100 --> 00:45:41,806 to make sure the wild population stays strong. 653 00:45:41,806 --> 00:45:44,575 There are now a manageable 150 horses 654 00:45:44,575 --> 00:45:48,379 on this side of the island. 655 00:45:48,379 --> 00:45:50,481 That number falls firmly in line 656 00:45:50,481 --> 00:45:58,155 with the ecologist's recommendations. 657 00:45:58,155 --> 00:45:59,657 The two herds are both considered 658 00:45:59,657 --> 00:46:06,163 conservation success stories. 659 00:46:06,163 --> 00:46:08,132 With proper population control 660 00:46:08,132 --> 00:46:11,769 the hope is the sun will never set on the empire 661 00:46:11,769 --> 00:46:21,512 of the Assateague Island horses. 662 00:46:21,512 --> 00:46:22,713 NARRATOR: Thousands of years ago 663 00:46:22,713 --> 00:46:26,817 animals like donkeys, pigs and horses 664 00:46:26,817 --> 00:46:30,755 became reliant on their owners. 665 00:46:30,755 --> 00:46:33,491 Likewise, humans came to rely on them, 666 00:46:33,491 --> 00:46:38,329 bringing them with us as we traveled the globe. 667 00:46:38,329 --> 00:46:41,766 But when animals are abandoned in strange new lands, 668 00:46:41,766 --> 00:46:47,304 the consequences are unpredictable. 669 00:46:47,304 --> 00:46:49,707 Controlling the population of feral species 670 00:46:49,707 --> 00:46:51,742 remains an ongoing challenge 671 00:46:51,742 --> 00:46:58,182 for conservationists around the globe. 672 00:46:58,182 --> 00:47:00,117 These empires gone wild 673 00:47:00,117 --> 00:47:02,319 struggle with depleted ecosystems 674 00:47:02,319 --> 00:47:14,065 and new relationships with humans. 675 00:47:14,065 --> 00:47:15,666 As these herds, 676 00:47:15,666 --> 00:47:17,068 bands 677 00:47:17,068 --> 00:47:19,136 and sounders 678 00:47:19,136 --> 00:47:20,738 continue to try to find harmony 679 00:47:20,738 --> 00:47:22,573 for their 680 00:47:22,573 --> 00:47:28,579 for their animal empires. 681 00:47:30,081 --> 00:47:40,124 ♪ THEME MUSIC ♪ 682 00:47:40,124 --> 00:47:54,438 ♪ THEME MUSIC ♪