1 00:00:01,434 --> 00:00:04,926 In the beginning, there is the fertilized egg. 2 00:00:05,438 --> 00:00:08,100 Its form couldn't be simpler. 3 00:00:09,209 --> 00:00:11,473 But this will change. 4 00:00:12,612 --> 00:00:16,810 It's a piece of work to craft a creature from a single cell. 5 00:00:24,124 --> 00:00:26,024 By the time it enters the world, 6 00:00:26,159 --> 00:00:31,290 every living thing has experienced an odyssey of alteration. 7 00:00:35,301 --> 00:00:38,498 Change doesn't stop with hatching or birth. 8 00:00:38,638 --> 00:00:42,699 Growing up is also a story of transformation. 9 00:00:42,842 --> 00:00:48,644 A newborn kangaroo can grow over 50,000 times in weight. 10 00:01:03,797 --> 00:01:06,960 Some creatures do far more than simply grow up. 11 00:01:07,100 --> 00:01:09,898 They reinvent themselves. 12 00:01:15,208 --> 00:01:20,145 A fish can start life as a female but end up as a male. 13 00:01:21,581 --> 00:01:26,541 A bird can grow or shrink a brain area for song to suit the season. 14 00:01:28,688 --> 00:01:31,156 Polliwogs become frogs. 15 00:01:32,125 --> 00:01:34,719 Caterpillars turn into butterflies. 16 00:01:34,861 --> 00:01:37,887 We learn few more curious facts than these. 17 00:01:38,031 --> 00:01:43,867 But it's easy to lose sight of just how astonishing these changes are! 18 00:01:44,003 --> 00:01:47,962 And even weirder transformers live among us. 19 00:01:48,108 --> 00:01:51,202 Turn and face the strange. 20 00:01:51,344 --> 00:01:54,142 Meet the body changers. 21 00:02:48,501 --> 00:02:50,025 "Hey, Emma, come here!" 22 00:02:53,540 --> 00:02:56,373 Compared to the epic alteration of a caterpillar, 23 00:02:56,509 --> 00:02:59,603 our own changes may seem subtle. 24 00:02:59,746 --> 00:03:02,374 But there's no denying that kids change shape 25 00:03:02,515 --> 00:03:04,813 as they turn into grownups. 26 00:03:05,451 --> 00:03:09,217 The brain kicks off our own sexual transformations. 27 00:03:10,523 --> 00:03:14,926 Girls tend to get curvier from estrogen and other hormones. 28 00:03:32,712 --> 00:03:36,113 A child's body and that of many other young creatures 29 00:03:36,249 --> 00:03:40,652 changes shape when it reaches the age for reproduction. 30 00:03:40,787 --> 00:03:43,654 These alterations prepare us to compete for mates, 31 00:03:43,790 --> 00:03:46,384 to have babies, and to care for them. 32 00:04:05,111 --> 00:04:07,375 Boys change in their own way. 33 00:04:07,513 --> 00:04:09,003 They add muscle. 34 00:04:09,148 --> 00:04:10,911 Shoulders become broader. 35 00:04:11,050 --> 00:04:13,018 The body gets hairier. 36 00:04:13,152 --> 00:04:16,986 Vocal cords lengthen as does the jaw. 37 00:04:17,123 --> 00:04:21,583 A child's journey to adulthood is a long one. 38 00:04:27,834 --> 00:04:30,325 A grownup is not just a scaledup kid, 39 00:04:30,470 --> 00:04:33,462 but one rebuilt from head to toe. 40 00:04:33,606 --> 00:04:35,767 Look back at the odyssey of growing up, 41 00:04:35,908 --> 00:04:38,900 and we see that even our faces change shape, 42 00:04:39,045 --> 00:04:45,314 starting in infancy with small chins, huge eyes, and plump cheeks. 43 00:04:57,297 --> 00:04:59,288 We are all body changers 44 00:04:59,432 --> 00:05:02,868 when it comes to growing up and growing old. 45 00:05:06,673 --> 00:05:08,072 It may be no accident that 46 00:05:08,207 --> 00:05:12,200 many baby animals have different face shapes from their parents. 47 00:05:12,345 --> 00:05:15,337 Adults fiind baby features irresistible 48 00:05:15,481 --> 00:05:19,474 a hardwired system that promotes infant care. 49 00:05:35,635 --> 00:05:38,729 Silvered leaf monkeys have DayGlo offspring. 50 00:05:38,871 --> 00:05:40,998 No one knows why, unless it's a reminder 51 00:05:41,140 --> 00:05:45,440 to roughandtumble mothers to handle the baby with care. 52 00:05:47,180 --> 00:05:50,240 The young and old of many animals have different colors 53 00:05:50,383 --> 00:05:55,320 sometimes to conceal newborns that are less able to flee danger. 54 00:06:08,401 --> 00:06:15,000 A young, sexually mature male orangutan has a distinguished, mournful visage. 55 00:06:16,843 --> 00:06:20,301 But in middle age, his face changes shape. 56 00:06:20,446 --> 00:06:24,041 His new jowly look is a badge of power. 57 00:06:31,591 --> 00:06:35,357 Changes in our own faces tell many stories. 58 00:06:35,495 --> 00:06:38,123 A face that forms symmetrically in the womb 59 00:06:38,264 --> 00:06:40,391 and stays that way through adulthood 60 00:06:40,533 --> 00:06:44,526 can be a mark of good nutrition and resistance to disease. 61 00:06:44,670 --> 00:06:50,302 Is it any wonder we are highly attuned to symmetry and fiind it beautiful? 62 00:06:51,110 --> 00:06:55,945 Old age brings new changes as our faces transform again, 63 00:06:56,082 --> 00:07:01,714 keeping a faithful record of wear and tear, loves and losses. 64 00:07:16,269 --> 00:07:20,262 As we change ourselves in the subtle ways that human beings do, 65 00:07:20,406 --> 00:07:25,105 we're surrounded by creatures that become entirely new. 66 00:07:27,180 --> 00:07:28,408 Around us are animals 67 00:07:28,548 --> 00:07:34,248 that live out the youthful fantasy of sprouting wings and flying like a bird. 68 00:07:38,024 --> 00:07:40,390 But we also share the world with animals 69 00:07:40,526 --> 00:07:44,656 whose stories of change echo darker myths. 70 00:07:59,278 --> 00:08:02,270 Hercules' enemy, the manyheaded Hydra, 71 00:08:02,415 --> 00:08:06,909 sprouted two new heads for every one lopped off. 72 00:08:07,053 --> 00:08:09,783 Nature nearly matches legend. 73 00:08:09,922 --> 00:08:15,326 The salamander has powers of regeneration bordering on the magical. 74 00:08:15,461 --> 00:08:19,329 It will need these talents, for it lives not in a fairy tale, 75 00:08:19,465 --> 00:08:23,094 but rather in a world of real dangers. 76 00:08:36,282 --> 00:08:40,378 A redeared slider enters the stream. 77 00:08:45,024 --> 00:08:49,222 The salamander picks an unlucky moment for a swim. 78 00:08:50,863 --> 00:08:55,994 It's a vulnerable creature, unarmored and undisguised. 79 00:09:27,266 --> 00:09:30,895 The turtle has nipped off the salamander's hind leg. 80 00:09:31,537 --> 00:09:36,565 Over three months, the creature miraculously transforms itself 81 00:09:36,709 --> 00:09:39,906 back to an earlier stage of life. 82 00:09:40,046 --> 00:09:44,039 The genes that grew the leg in the first place are activated again. 83 00:09:44,183 --> 00:09:49,052 The new leg will be indistinguishable from the original. 84 00:09:54,360 --> 00:09:56,692 Unique among animals with backbones, 85 00:09:56,829 --> 00:09:59,923 the salamander can regrow not just limbs 86 00:10:00,066 --> 00:10:04,799 but the lens of the eye and even part of the brain. 87 00:10:04,937 --> 00:10:08,373 This beast can survive a bite to the head! 88 00:10:08,507 --> 00:10:11,271 The Hydra lives. 89 00:10:15,314 --> 00:10:20,775 The power to change shape or color offers a special edge in life. 90 00:10:27,026 --> 00:10:30,393 Some creatures change to stay hidden. 91 00:10:30,529 --> 00:10:34,625 Others transform to fiind new kinds of food. 92 00:10:35,501 --> 00:10:38,800 Still other animals change for upward mobility 93 00:10:38,938 --> 00:10:42,374 for the chance to fly or leap to another pond. 94 00:10:48,314 --> 00:10:54,184 This lake is home to two body changers that can be lifelong rivals. 95 00:10:57,957 --> 00:11:03,793 A dragonfly nymph spends the first part of its life beneath the surface. 96 00:11:10,269 --> 00:11:14,262 Everything about this creature seems honed for water. 97 00:11:15,574 --> 00:11:18,543 It is tapered for speed. 98 00:11:19,211 --> 00:11:24,672 Its head has powerful jaws and huge eyesthe better to catch prey with. 99 00:11:26,185 --> 00:11:31,953 It breathes through an anal gill also handy for jet propulsion. 100 00:11:32,491 --> 00:11:35,255 It's hard to believe that this pond predator 101 00:11:35,394 --> 00:11:42,664 sleek as a torpedo, accurate and deadly will one day take to the air. 102 00:11:45,271 --> 00:11:47,364 Wings are already forming. 103 00:11:47,506 --> 00:11:51,067 An amazing makeover is beginning. 104 00:11:53,646 --> 00:11:55,705 But the dragonfly will not be able to 105 00:11:55,848 --> 00:12:00,547 complete its body change without regular meals. 106 00:12:02,588 --> 00:12:06,422 Sharing the pond are gray treefrog tadpoles. 107 00:12:06,559 --> 00:12:10,928 You can't get any fishier than this without actually being a fish. 108 00:12:11,063 --> 00:12:14,396 A tadpole breathes through internal gills. 109 00:12:14,533 --> 00:12:19,027 Its long flat tail propels it like a fish's tail. 110 00:12:20,372 --> 00:12:26,504 Inside, powerful front legs have formed and are nearly ready to burst out. 111 00:12:26,645 --> 00:12:32,606 But not every ungainly swimmer will live to be reborn as an elegant leaper. 112 00:12:32,752 --> 00:12:35,380 With a secret weapon locked and loaded, 113 00:12:35,521 --> 00:12:39,855 the dragonfly nymph waits for an opportunity. 114 00:12:44,463 --> 00:12:49,992 Folded up under the nymph's head is a hinged lip with a grasping tip. 115 00:12:50,136 --> 00:12:53,663 This tadpole's dreams of frogdom are dashed. 116 00:12:53,806 --> 00:12:57,071 But in these death throes, a chemical is released 117 00:12:57,209 --> 00:13:02,010 which fellow tadpoles take to heart or to tail. 118 00:13:02,148 --> 00:13:07,108 In two weeks, tadpoles in the area transform remarkably. 119 00:13:07,253 --> 00:13:09,653 Their tails turn a shade of red. 120 00:13:09,789 --> 00:13:12,690 The colored tail may protect tadpoles from attack 121 00:13:12,825 --> 00:13:16,761 like a neon sign flashing "Don't Eat." 122 00:13:20,232 --> 00:13:22,757 Why this works, no one is sure, 123 00:13:22,902 --> 00:13:27,339 but there's no need to turn tail with a tail turned red. 124 00:13:28,974 --> 00:13:31,966 The pond is abuzz with changing bodies. 125 00:13:32,111 --> 00:13:35,205 Not only are tadpoles about to turn into frogs, 126 00:13:35,347 --> 00:13:37,474 they've already changed colors. 127 00:13:37,616 --> 00:13:42,212 At the age of five weeks, tadpoles, both red and cleartailed, 128 00:13:42,354 --> 00:13:44,686 shed their underwater ways. 129 00:13:44,824 --> 00:13:47,588 Rear legs emerge slowly. 130 00:13:47,726 --> 00:13:50,126 Front legs pop out of gill slits. 131 00:13:50,262 --> 00:13:53,425 The tail is absorbed. 132 00:14:05,211 --> 00:14:07,907 This frog may not have turned into a prince, 133 00:14:08,047 --> 00:14:12,347 but the tadpole's transformation is no less astonishing. 134 00:14:12,484 --> 00:14:15,920 An airbreathing, bugeating, lillyhopping, sweetsinging adult 135 00:14:16,055 --> 00:14:20,992 has emerged from a silent scumsucking swimmer with gills. 136 00:14:29,301 --> 00:14:32,828 Now is the dragonfly nymph's time to change. 137 00:14:32,972 --> 00:14:35,566 It's been lurking in the shallows by the shore, 138 00:14:35,708 --> 00:14:40,941 waiting for just the right moment to abandon the water forever. 139 00:14:41,080 --> 00:14:44,015 Tonight is perfectcalm, 140 00:14:44,149 --> 00:14:49,382 since rain or wind could dislodge the dragonfly at a vulnerable moment. 141 00:14:49,521 --> 00:14:54,891 The nymph has crawled out of the water and fastened itself to a stem. 142 00:14:55,794 --> 00:14:58,991 It is now committed to the air. 143 00:15:07,539 --> 00:15:12,306 A brand new creature emerges from the old. 144 00:15:12,978 --> 00:15:16,436 The husk of the nymph splits open. 145 00:15:25,391 --> 00:15:30,454 In a single magical hour, an adult struggles out. 146 00:16:01,093 --> 00:16:05,257 At first, its goggle eyes look like deflated beach balls. 147 00:16:05,397 --> 00:16:08,366 But soon they are pumped up to full size 148 00:16:08,500 --> 00:16:12,163 some of the keenest eyes in the insect realm. 149 00:16:19,645 --> 00:16:21,840 In the remaining hours before dawn, 150 00:16:21,981 --> 00:16:26,111 the dragonfly pumps blood into its soft, wet wings, 151 00:16:26,251 --> 00:16:28,685 doubling their length. 152 00:16:52,711 --> 00:16:56,477 The dragonfly has changed from a jetpowered aquatic hunter 153 00:16:56,615 --> 00:16:58,742 armed with a hydraulic spear 154 00:16:58,884 --> 00:17:03,617 to a peerless aerialist that will stalk on the wing. 155 00:17:11,930 --> 00:17:17,095 About two hours after emerging, the dragonfly takes flight. 156 00:17:19,371 --> 00:17:21,601 Once master of the pond bottom, 157 00:17:21,740 --> 00:17:25,938 the dragonfly now controls the air space above. 158 00:17:26,845 --> 00:17:30,542 No other insect devotes as big a share of its body weight 159 00:17:30,682 --> 00:17:33,810 to flight muscles as the dragonfly. 160 00:17:39,892 --> 00:17:44,955 Scuba certification has been traded in for a pilot's license. 161 00:17:49,835 --> 00:17:54,363 As larvae, dragonflies once hunted tadpoles. 162 00:17:54,506 --> 00:17:59,808 Adult frogs sometimes have the chance to even the score. 163 00:18:03,782 --> 00:18:06,683 A dragonfly is a curve ball on the wing. 164 00:18:06,819 --> 00:18:09,287 There's nothing wrong with the occasional whiff 165 00:18:09,421 --> 00:18:13,255 if now and then you connect with a solid double. 166 00:18:18,063 --> 00:18:22,056 Just as body changes can take place in individual creatures, 167 00:18:22,201 --> 00:18:25,637 so they can occur across generations. 168 00:18:25,771 --> 00:18:28,137 That's evolution. 169 00:18:31,410 --> 00:18:35,847 Natural selection is the long process of picking winners and losers 170 00:18:35,981 --> 00:18:40,611 among organisms that differ slightly from their parents. 171 00:18:40,752 --> 00:18:47,316 Without bodychanging over generations, evolution would come to a standstill. 172 00:18:47,459 --> 00:18:54,160 As it is, change adds to change to create the entire parade of life. 173 00:19:04,676 --> 00:19:09,113 Life may have begun with a blob that by chance transformed. 174 00:19:09,248 --> 00:19:11,079 When alterations were successful, 175 00:19:11,216 --> 00:19:15,550 the transformer thrived and transformed again. 176 00:19:16,421 --> 00:19:18,685 One of natural selection's winning picks 177 00:19:18,824 --> 00:19:23,022 is the trick of morphing during a single lifetime. 178 00:19:23,162 --> 00:19:25,687 Plankton is a potpourri of larvae 179 00:19:25,831 --> 00:19:30,859 body changers of many species at an early stage of life. 180 00:19:31,403 --> 00:19:33,667 Creatures like this have an edge: 181 00:19:33,805 --> 00:19:37,502 Each stage can be honed for a different job. 182 00:19:37,643 --> 00:19:42,478 Now they are shaped for spreading arounddrifting on the currents. 183 00:19:42,614 --> 00:19:45,913 Soon these beasts will be changed beyond recognition 184 00:19:46,051 --> 00:19:50,511 into new forms tailored for feeding and reproduction. 185 00:20:02,968 --> 00:20:05,630 One member of the plankton, a crab larva, 186 00:20:05,771 --> 00:20:09,571 starts life with scant resemblance to its parents. 187 00:20:09,708 --> 00:20:15,408 It shares the ocean with another tiny drifterthe seaslug. 188 00:20:17,149 --> 00:20:18,810 This relative of the snail 189 00:20:18,951 --> 00:20:24,184 hatches wearing a transparent shell a suit of crystalline armor. 190 00:20:24,323 --> 00:20:27,622 Seaslug and crab, similar as larvae, 191 00:20:27,759 --> 00:20:33,561 may confront each other as adults, as different as two animals can be. 192 00:20:37,836 --> 00:20:39,360 Having shed its shell, 193 00:20:39,504 --> 00:20:43,907 the seaslug eventually becomes an adult four inches long. 194 00:20:44,042 --> 00:20:48,570 It now has a new organ a feeding hood. 195 00:21:01,593 --> 00:21:07,998 The billowy hood caresses eel grass to catch food like skeleton shrimp. 196 00:21:21,880 --> 00:21:26,544 Like a submarine Venus fly trap, the seaslug closes up, 197 00:21:26,685 --> 00:21:31,816 trapping prey like skeleton shrimp with a zipperlike seal. 198 00:21:37,195 --> 00:21:40,722 Growing on the seaslug's back are other new organs 199 00:21:40,866 --> 00:21:45,303 fleshy paddles that will soon save its life. 200 00:21:52,277 --> 00:21:54,040 As the seaslug feeds, 201 00:21:54,179 --> 00:21:58,582 it is being watched by its former planktonmate. 202 00:22:00,786 --> 00:22:04,586 The crab has changed into a formidable scavenger 203 00:22:04,723 --> 00:22:08,489 with molarlike grinders on its claws. 204 00:22:25,844 --> 00:22:31,908 Blind except perhaps to light and dark the seaslug approaches danger. 205 00:22:50,369 --> 00:22:56,001 The crab pinches at the seaslug as hard to grab as a water balloon. 206 00:22:57,075 --> 00:22:59,908 Finally the crab gets purchase. 207 00:23:00,045 --> 00:23:02,980 But it gets only a small serving of seaslug, 208 00:23:03,115 --> 00:23:06,414 whose paddles pop off by design. 209 00:23:14,626 --> 00:23:18,995 The seaslug swims away with wild undulations. 210 00:23:21,400 --> 00:23:25,302 Only a stump remains where once there was a paddle. 211 00:23:25,437 --> 00:23:29,237 The missing organ may eventually grow back 212 00:23:33,412 --> 00:23:39,408 Once a tiny drifter, this body changer is now rebuilt for escape. 213 00:23:41,052 --> 00:23:45,250 Up the water column without a paddle, the seaslug leaves the crab, 214 00:23:45,390 --> 00:23:49,622 its fellow transformer, with a meager souvenir. 215 00:24:06,011 --> 00:24:10,744 Transformation is not just the privilege of living things. 216 00:24:10,882 --> 00:24:15,376 The morphing of clouds may offer nothing more than delight. 217 00:24:15,520 --> 00:24:21,652 The morphing of bodies serves a more important goal: Survival. 218 00:24:22,294 --> 00:24:26,822 In the Arizona desert, the weather shifts late in June. 219 00:24:26,965 --> 00:24:31,732 After eight crispy months, skies darken. 220 00:24:33,672 --> 00:24:36,368 The monsoon has arrived. 221 00:24:55,227 --> 00:25:00,187 The pounding of the rain has stirred strange creatures beneath the soil. 222 00:25:00,999 --> 00:25:03,365 In this small, evaporating pond, 223 00:25:03,502 --> 00:25:07,370 animals race against the clock to transform. 224 00:25:10,108 --> 00:25:14,772 Tadpoles of the spadefoot toad must absorb their tails, 225 00:25:14,913 --> 00:25:17,404 grow lungs, sprout legs. 226 00:25:17,549 --> 00:25:20,279 They must transform from fishlike swimmers 227 00:25:20,418 --> 00:25:23,876 with gills to hopping airbreathers. 228 00:25:24,022 --> 00:25:27,856 If changing from tadpole to toad isn't miracle enough, 229 00:25:27,993 --> 00:25:31,656 tadpoles of this species have two ways to do it 230 00:25:31,796 --> 00:25:35,755 the nice way and the notsonice. 231 00:25:37,035 --> 00:25:40,402 In this hot summer, the pond is shrinking quickly. 232 00:25:40,539 --> 00:25:45,602 It could become a deathtrap a cauldron of bouillabaisse. 233 00:25:46,778 --> 00:25:48,439 As the water level drops, 234 00:25:48,580 --> 00:25:52,914 time is running out for the tadpoles to become toads. 235 00:25:53,685 --> 00:25:58,179 Meanwhile, another creature joins the fray. 236 00:26:00,892 --> 00:26:06,228 Fairy shrimp may have lain dormant underground as eggs for years, 237 00:26:06,364 --> 00:26:10,767 waiting for just the right conditions to rush through their lives. 238 00:26:10,902 --> 00:26:14,065 As the pool dries up, it gets more crowded. 239 00:26:14,205 --> 00:26:17,663 Tadpoles bump into more and more of these crustaceans. 240 00:26:17,809 --> 00:26:19,970 Advantage: Tadpole. 241 00:26:20,946 --> 00:26:24,040 If they end up snacking on lots of Sonoran scampi, 242 00:26:24,182 --> 00:26:28,312 the tadpoles sense that their pond is shrinking fast. 243 00:26:28,453 --> 00:26:30,318 There's something about fairy shrimp 244 00:26:30,455 --> 00:26:34,186 that throws a chemical switch inside some of the tadpoles. 245 00:26:34,326 --> 00:26:38,592 And these gentle browsers now begin to transform into brutes 246 00:26:38,730 --> 00:26:41,290 that will stop at nothing to become a toad. 247 00:26:41,433 --> 00:26:45,130 Some of the tadpoles are turning into cannibals! 248 00:26:45,270 --> 00:26:48,797 This is bodychanging with attitude. 249 00:26:48,940 --> 00:26:52,671 The cannibals are lighter in color and larger. 250 00:26:54,279 --> 00:26:59,842 A huge muscle forms in the jaw the better to grab their neighbors with. 251 00:27:05,757 --> 00:27:09,124 We're no longer on golden pond. 252 00:27:09,260 --> 00:27:14,220 The cannibals grow at breakneck speed on their unneighborly diet. 253 00:27:14,366 --> 00:27:19,531 On the fast track they will need only twoandahalf weeks to become toads. 254 00:27:19,671 --> 00:27:24,938 The slower, mildmannered tadpoles need six weeks to grow up. 255 00:27:25,076 --> 00:27:29,570 The extra time helps them become healthier adults than the cannibals. 256 00:27:29,714 --> 00:27:33,081 But often in the desert, time is a luxury. 257 00:27:33,218 --> 00:27:37,086 And the race goes to the swift and brutal. 258 00:27:37,222 --> 00:27:40,214 It was a remarkable turning point in evolution 259 00:27:40,358 --> 00:27:43,759 when a fish transformed to emerge from the sea, 260 00:27:43,895 --> 00:27:47,592 gulp air and drag itself around. 261 00:27:47,732 --> 00:27:54,729 But what took eons in evolution is an everyday occurrence in tadpoles. 262 00:27:57,909 --> 00:28:02,642 To reach adulthood, spadefoot toads must live fast and hard, 263 00:28:02,781 --> 00:28:08,981 then dig down into cool damp soil before the next drought arrives. 264 00:28:15,060 --> 00:28:20,930 For others in the desert, the season of change has also arrived. 265 00:28:31,042 --> 00:28:37,311 On an acacia blossom, an egg barely visible to the human eye hatches. 266 00:28:44,055 --> 00:28:47,081 A bristled beast emerges. 267 00:28:51,196 --> 00:28:53,994 This caterpillar has a problem. 268 00:28:54,132 --> 00:28:57,067 If it's ever going to become a butterfly, 269 00:28:57,202 --> 00:29:00,660 it must first survive its life as a larva. 270 00:29:00,805 --> 00:29:05,606 The desert is alive with predators like ants and wasps. 271 00:29:05,744 --> 00:29:09,612 This caterpillar has an ingenious defense. 272 00:29:10,715 --> 00:29:13,445 It will soon enlist one of its enemies, 273 00:29:13,585 --> 00:29:20,354 but only after it transforms to develop special organs for manipulating ants. 274 00:29:28,700 --> 00:29:33,433 At the base of the acacia tree, ants have dug a nest. 275 00:29:37,442 --> 00:29:42,038 Most ants like nothing better than dismantling caterpillars. 276 00:29:43,248 --> 00:29:46,240 But these ants love themintact. 277 00:29:46,384 --> 00:29:49,285 They will protect the caterpillar. 278 00:29:51,589 --> 00:29:55,184 That's because the ants march to the beat of a different drummer. 279 00:29:55,326 --> 00:29:58,193 The caterpillar has become the drummer. 280 00:29:58,329 --> 00:30:00,229 This is the sound the caterpillar makes 281 00:30:00,365 --> 00:30:05,029 with body vibrations so tiny we can't see them. 282 00:30:06,171 --> 00:30:11,609 But ants feel the beat through twigs and stems and come running. 283 00:30:14,279 --> 00:30:17,737 A strange rendezvous of two very different creatures 284 00:30:17,882 --> 00:30:20,373 is about to take place. 285 00:30:25,490 --> 00:30:28,220 The caterpillar has, in effect, shouted to the ants, 286 00:30:28,359 --> 00:30:30,452 "Come and get it!" 287 00:30:33,965 --> 00:30:35,455 It's not a ploy. 288 00:30:35,600 --> 00:30:41,038 The caterpillar doles out sugary droplets which the ants lap up. 289 00:30:48,179 --> 00:30:50,670 For the price of a few servings of food, 290 00:30:50,815 --> 00:30:54,581 the caterpillar is surrounded by friendly ants. 291 00:30:54,719 --> 00:30:56,311 Not a bad thing to have the neighborhood 292 00:30:56,454 --> 00:30:57,921 toughs at your beck and call 293 00:30:58,056 --> 00:31:02,755 when you have a soft body and a nasty array of predators. 294 00:31:03,494 --> 00:31:09,057 This remarkable relationship will last for most of the caterpillar's life. 295 00:31:13,538 --> 00:31:18,373 The caterpillar now transforms into a new stage. 296 00:31:21,145 --> 00:31:24,842 Tentacles have appeared strange chemical transmitters 297 00:31:24,983 --> 00:31:27,918 that seem to rile up the ants. 298 00:31:29,754 --> 00:31:34,817 The caterpillar needs the ants to be ferocious: Danger is near. 299 00:31:36,194 --> 00:31:41,222 Another kind of ant lives nearby a predatory species. 300 00:31:58,716 --> 00:32:01,446 An enemy ant has grabbed the caterpillar. 301 00:32:01,586 --> 00:32:05,716 The friendly ants rally in a desperate tugofwar. 302 00:32:11,296 --> 00:32:14,094 Not all battles can be won. 303 00:32:14,232 --> 00:32:16,757 But without the aid of bodyguard ants, 304 00:32:16,901 --> 00:32:21,270 not as many caterpillars would live to become butterflies. 305 00:32:21,973 --> 00:32:26,467 About ten days after hatching, the caterpillar descends the tree. 306 00:32:26,611 --> 00:32:31,014 It's hard to believe this creature will soon shed its wormy form, 307 00:32:31,149 --> 00:32:34,380 sprout wings and head for the heavens. 308 00:32:34,519 --> 00:32:37,920 But that is the miracle of a caterpillar. 309 00:32:38,056 --> 00:32:44,017 Down in the enclave of the ant nest, the caterpillar is reborn as a pupa. 310 00:32:44,162 --> 00:32:47,063 Hunkered inside what looks like a sarcophagus, 311 00:32:47,198 --> 00:32:51,328 the pupa is a creature in the midst of a total makeover. 312 00:32:51,469 --> 00:32:53,596 Nerves are being rewired. 313 00:32:53,738 --> 00:32:58,072 Old organs are dissolving; new ones are being built. 314 00:32:58,209 --> 00:33:00,507 The ants tend this defenseless animal 315 00:33:00,645 --> 00:33:03,808 even though it will no longer feed them. 316 00:33:04,482 --> 00:33:05,414 After ten days, 317 00:33:05,550 --> 00:33:10,954 one of the most radical redesigns in all of nature is complete. 318 00:33:11,089 --> 00:33:15,992 The pupa has become an adult, a butterfly. 319 00:33:16,127 --> 00:33:20,826 This creature's long relationship with ants is now over. 320 00:33:20,965 --> 00:33:23,365 The butterfly struggles to emerge. 321 00:33:23,501 --> 00:33:26,129 It must move quickly. 322 00:33:26,270 --> 00:33:29,865 In fact, if the butterfly isn't out of the nest in minutes, 323 00:33:30,008 --> 00:33:31,942 it will be devoured by the same ants 324 00:33:32,076 --> 00:33:35,773 that protected it for almost its entire life. 325 00:33:42,620 --> 00:33:47,023 As larvae, these creatures were basically enormous digestive tracts 326 00:33:47,158 --> 00:33:49,854 hauled around on caterpillar treads. 327 00:33:49,994 --> 00:33:55,125 As adults, they are flying machines dedicated to sex. 328 00:34:50,655 --> 00:34:54,318 If we couldn't witness a caterpillar turn into a butterfly, 329 00:34:54,459 --> 00:34:58,088 we'd never believe they were the same animal. 330 00:34:59,097 --> 00:35:05,036 It's as astounding as a Cuisinart transforming into a 747. 331 00:35:21,119 --> 00:35:25,317 Some animals undergo one major transformation in their lives. 332 00:35:25,456 --> 00:35:29,119 Others change fashions every year with the seasons. 333 00:35:29,260 --> 00:35:31,820 Dogs may wear heavy coats in winter. 334 00:35:31,963 --> 00:35:36,696 But lengthening days will cause the fiine underhairs to drop out. 335 00:35:36,834 --> 00:35:41,669 Soon, this dog will be cooler in his new spring wardrobe. 336 00:35:41,806 --> 00:35:45,867 Some animals change not only their coat but their color. 337 00:35:46,010 --> 00:35:49,946 The arctic fox wears white for stealthy winter hunting. 338 00:35:50,081 --> 00:35:54,541 By summer, the coat is less than half as thick 339 00:35:55,620 --> 00:35:58,817 Arctic birds like the ptarmigan also change color. 340 00:35:58,956 --> 00:36:02,858 In summer, they're as mottled as the terrain. 341 00:36:05,196 --> 00:36:09,530 By winter, the ptarmigan is a bird of a different color. 342 00:36:13,504 --> 00:36:15,665 Other prey species like the arctic hare 343 00:36:15,806 --> 00:36:18,434 must track the seasons with their wardrobe. 344 00:36:18,576 --> 00:36:21,977 Understatement is de rigeur. 345 00:36:23,981 --> 00:36:27,678 If some animals change for the seasons on the outside, 346 00:36:27,818 --> 00:36:32,346 others are transforming on the inside. 347 00:36:32,490 --> 00:36:34,219 All over North America, 348 00:36:34,358 --> 00:36:39,796 redwing blackbirds prepare for spring with remarkable changes. 349 00:36:39,931 --> 00:36:44,459 Males arrive from winter havens to squabble for territories. 350 00:36:44,602 --> 00:36:47,537 No one gets a home without singing for it. 351 00:36:47,672 --> 00:36:50,232 But this male is out of practice. 352 00:36:50,374 --> 00:36:54,071 He hasn't sung much at all for half a year. 353 00:36:54,212 --> 00:36:57,375 But he's been quietly transforming. 354 00:36:57,515 --> 00:37:02,214 It's now opening day of a new season of song. 355 00:37:07,692 --> 00:37:12,459 The transformation was all in his headliterally. 356 00:37:14,098 --> 00:37:17,363 The blackbird is a brain changer. 357 00:37:17,501 --> 00:37:22,268 Over the past months, one tiny area in his brain devoted to song 358 00:37:22,406 --> 00:37:25,637 has more than doubled in volume. 359 00:37:37,188 --> 00:37:43,286 With his new swelled head, this male now woos females with song. 360 00:37:54,305 --> 00:37:59,299 When a female becomes all aflutter, the serenade has succeeded. 361 00:37:59,443 --> 00:38:03,038 The happy new couple flies off to the shrubbery. 362 00:38:03,180 --> 00:38:06,411 It's time for a little twointhebush. 363 00:38:11,188 --> 00:38:15,420 The burgeoning brain of the male may have kept the sexes in tune this season. 364 00:38:15,559 --> 00:38:21,156 Transformation promoted communication which helped launch the next generation. 365 00:38:37,648 --> 00:38:42,415 Late in the summer, blackbirds glean the fields for the last easy morsels. 366 00:38:42,553 --> 00:38:44,987 Males will transform once again. 367 00:38:45,122 --> 00:38:50,924 The brain's song area dwindles, along with sweet serenades for sex. 368 00:38:56,300 --> 00:39:00,566 Birds are in good company when it comes to changing for reproduction. 369 00:39:02,673 --> 00:39:03,765 For most of its life, 370 00:39:03,908 --> 00:39:09,505 a flowering plant makes stems and leaves, a single pattern repeated. 371 00:39:10,114 --> 00:39:14,847 But when the right conditions arrive of temperature, daylight, or rainfall 372 00:39:14,985 --> 00:39:17,954 a plant will suddenly transform, 373 00:39:18,089 --> 00:39:22,958 producing a brilliant package of sex and advertising. 374 00:39:25,730 --> 00:39:31,191 As one poet put it, "The flower is a leaf mad with love." 375 00:40:14,678 --> 00:40:19,547 Deer browse among blossoms, eating tender leaves and grasses. 376 00:40:20,151 --> 00:40:26,249 A once flowering feast is transformed into a pile of dung. 377 00:40:30,895 --> 00:40:33,329 In the leftovers of a deer's meal, 378 00:40:33,464 --> 00:40:37,867 two organisms will each struggle to survive. 379 00:40:38,469 --> 00:40:42,371 A fungus begins to grow threads invisible to the human eye. 380 00:40:42,506 --> 00:40:46,033 The fungus is transforming for reproduction. 381 00:40:46,177 --> 00:40:51,012 It shoots up stalks as tall as an eyelash is long. 382 00:40:51,749 --> 00:40:56,914 Each stem lifts ripening spores above the deer's ground zero. 383 00:41:01,792 --> 00:41:05,159 Meanwhile, tiny larvae are growing. 384 00:41:05,296 --> 00:41:08,288 The deer was infected with a roundworm. 385 00:41:08,432 --> 00:41:11,162 To survive, these wriggling parasites 386 00:41:11,302 --> 00:41:16,239 must leave their dump of a neighborhood to reach a new deer. 387 00:41:24,682 --> 00:41:27,583 So the worm climbs a fungus stalk 388 00:41:27,718 --> 00:41:31,017 Just below a black beret packed with spores, 389 00:41:31,155 --> 00:41:33,623 water pressure builds. 390 00:41:34,225 --> 00:41:39,322 When the cap bursts, spores can be shot up to eight feet away. 391 00:41:39,463 --> 00:41:42,432 And worms will fly. 392 00:42:26,010 --> 00:42:29,537 One of the parasites lands several feet away. 393 00:42:30,114 --> 00:42:34,574 A passing deer eats it an inadvertent diet of worms. 394 00:42:34,718 --> 00:42:36,777 The roundworm has found a host, 395 00:42:36,921 --> 00:42:41,187 and millions of scattered spores await their fate. 396 00:42:43,193 --> 00:42:44,125 Wintertime. 397 00:42:44,261 --> 00:42:47,094 And the living's hard in the far north. 398 00:42:47,231 --> 00:42:51,167 At least for a relative of the deercaribou. 399 00:42:55,773 --> 00:42:59,504 The landscape is littered with body parts. 400 00:42:59,643 --> 00:43:01,076 Antlers. 401 00:43:01,211 --> 00:43:06,274 Up to 20 pounds of bone, grown every year and discarded. 402 00:43:25,769 --> 00:43:28,465 Males start to grow antlers every spring 403 00:43:28,606 --> 00:43:32,337 a transformation from bald to bedecked. 404 00:43:34,044 --> 00:43:39,004 Antlers are living tissue crisscrossed with blood vessels and nerve endings. 405 00:43:39,149 --> 00:43:42,710 The sensitive fuzzy skin is called velvet. 406 00:43:43,687 --> 00:43:49,751 Each caribou has a signature pattern which can grow back year after year. 407 00:43:49,893 --> 00:43:51,588 It would be no less wondrous 408 00:43:51,729 --> 00:43:56,792 if we were to sprout a fresh arm the same armevery year. 409 00:44:07,645 --> 00:44:09,875 When antlers stop growing late in the summer, 410 00:44:10,014 --> 00:44:13,108 another transformation takes place. 411 00:44:23,494 --> 00:44:28,955 The tender velvet dies and is scraped away until it hangs in tatters. 412 00:44:29,099 --> 00:44:34,264 Each male is now crowned with spikes of unfeeling bone. 413 00:44:34,405 --> 00:44:38,239 Fighting is one reason for the male caribou's transformation. 414 00:44:38,375 --> 00:44:42,641 And this helps solve the mystery of why antlers shed their velvet: 415 00:44:42,780 --> 00:44:46,216 You can't fight a battle if your sword can bleed 416 00:44:46,350 --> 00:44:48,818 and is sensitive to the touch. 417 00:44:50,721 --> 00:44:53,781 Some creatures grow head weaponry every year. 418 00:44:53,924 --> 00:44:56,586 Others, only a single time. 419 00:44:56,727 --> 00:45:00,026 Altogether, male caribou have plenty of company 420 00:45:00,164 --> 00:45:03,463 when it comes to transformations for battle. 421 00:45:33,130 --> 00:45:36,156 If some animals transform what's on their head, 422 00:45:36,300 --> 00:45:39,565 others change what's in it. 423 00:45:43,373 --> 00:45:45,864 This male's appearance and his personality 424 00:45:46,009 --> 00:45:48,773 will transform with his fortunes. 425 00:45:48,912 --> 00:45:51,472 Meet a member of the cichlid family. 426 00:45:51,615 --> 00:45:55,483 He's something of a piscine Austin Powers. 427 00:45:56,053 --> 00:45:58,146 "Oh behave, baby!" 428 00:45:58,288 --> 00:46:01,314 He's the proud owner of a prime bachelor pad 429 00:46:01,458 --> 00:46:04,825 about one square foot of lake bottom. 430 00:46:05,963 --> 00:46:10,024 He's dressed for success or, rather, because of it. 431 00:46:10,167 --> 00:46:16,163 His dark stripes and sharp colors are the marks of a territory holder. 432 00:46:16,306 --> 00:46:19,901 Nearby lurks a male with the dull colors of a wannabe. 433 00:46:20,043 --> 00:46:22,534 In fact, he looks just like a female. 434 00:46:22,679 --> 00:46:27,446 If fish experience envy, this one covets his neighbor's life. 435 00:46:30,187 --> 00:46:34,248 The flashy bachelor invites a female over to suck gravel. 436 00:46:34,391 --> 00:46:37,986 This counts as fiine dining in these shallows. 437 00:46:38,128 --> 00:46:42,997 After dinner, the couple retires to the grotto for a little spawning. 438 00:46:45,002 --> 00:46:48,403 There's only so much a guy can take. 439 00:46:53,677 --> 00:46:55,736 The wannabe has switched on his colors 440 00:46:55,879 --> 00:46:59,838 a kind of warpaint to prepare for battle. 441 00:47:00,918 --> 00:47:02,249 The wannabe wins. 442 00:47:02,386 --> 00:47:04,752 And he is transformed by victory. 443 00:47:04,888 --> 00:47:06,981 He retains his bright colors. 444 00:47:07,124 --> 00:47:08,887 His grievances are redressed 445 00:47:09,026 --> 00:47:13,986 as much as he himself has been redressed in the wardrobe of a winner. 446 00:47:14,131 --> 00:47:19,068 A more profound transformation will soon take place inside his body. 447 00:47:19,203 --> 00:47:22,798 In a week his gonads will plump up thirtyfold in weight 448 00:47:22,940 --> 00:47:29,072 and a brain area dedicated to sex will increase eight times in volume. 449 00:47:29,213 --> 00:47:34,446 At last the new bachelor is ready to take his enlarged gonads for a spin. 450 00:47:35,085 --> 00:47:37,815 Guided by his bigger brain area for sex, 451 00:47:37,955 --> 00:47:43,018 he courts a female with macho motions and furling fiins. 452 00:47:43,727 --> 00:47:48,061 But no male holds a longterm lease in these gravel beds. 453 00:47:49,099 --> 00:47:54,332 The new owner soon discovers the high cost of upkeep for his pad. 454 00:47:54,471 --> 00:47:58,965 Neighboring bachelors are always testing the lot lines. 455 00:48:00,244 --> 00:48:02,769 A neighbor attacks. 456 00:48:40,484 --> 00:48:42,975 The new territory holder is defeated. 457 00:48:43,120 --> 00:48:45,520 He switches off his fancy colors. 458 00:48:45,656 --> 00:48:49,558 His gonads and brain region for sex will soon shrink 459 00:48:49,693 --> 00:48:52,958 He rejoins the ranks of the wannabes. 460 00:48:54,932 --> 00:48:56,229 Some body changers 461 00:48:56,366 --> 00:49:01,429 save their most dramatic transformations for the end of life. 462 00:49:01,571 --> 00:49:04,165 Sockeye salmon are beckoned from the ocean 463 00:49:04,308 --> 00:49:08,642 back to the Alaskan streams where many hatched five years ago. 464 00:49:08,779 --> 00:49:14,843 Some must travel hundreds of miles in an odyssey that can take weeks. 465 00:49:15,552 --> 00:49:16,519 Along the way, 466 00:49:16,653 --> 00:49:21,852 salmon will undergo one of the most remarkable changes in all of nature. 467 00:49:21,992 --> 00:49:25,519 Head shape starts to change. 468 00:49:26,997 --> 00:49:30,455 Every salmon will die by the journey's end. 469 00:49:30,600 --> 00:49:31,760 The only question is 470 00:49:31,902 --> 00:49:35,963 whether they will get the chance to complete their transformation. 471 00:49:37,074 --> 00:49:42,239 Many will be stopped here by a terrible gauntlet of brown bears. 472 00:49:54,191 --> 00:49:56,159 On this journey of the condemned, 473 00:49:56,293 --> 00:50:00,627 the salmon throw themselves upriver with abandon. 474 00:50:51,181 --> 00:50:54,309 The salmon that escape, especially the males, 475 00:50:54,451 --> 00:50:58,285 will now carry on with their transformation. 476 00:51:00,991 --> 00:51:04,188 The head turns green and body red 477 00:51:04,327 --> 00:51:09,196 as the fish prepare to die on their own terms. 478 00:51:10,867 --> 00:51:12,858 Few have made it this far. 479 00:51:13,003 --> 00:51:16,268 Fewer yet will fimish the transformation. 480 00:51:16,406 --> 00:51:21,969 Approaching the spawning grounds, the males achieve their fiinal shape. 481 00:51:24,047 --> 00:51:27,414 A sleek silvery male, over a few weeks, 482 00:51:27,551 --> 00:51:32,955 transforms into a gaudy hunchback with a toothy grimace. 483 00:51:34,124 --> 00:51:40,222 The skin turns smooth and unfishlike as the body absorbs its scales. 484 00:51:53,910 --> 00:51:55,878 In tatters after their journey, 485 00:51:56,012 --> 00:51:59,106 salmon arrive in the shallows where they hatched. 486 00:51:59,249 --> 00:52:01,979 They've lost up to a third of their weight. 487 00:52:02,119 --> 00:52:04,587 Not to mention their looks. 488 00:52:05,355 --> 00:52:10,918 Only one in a thousand has completed this harrowing roundtrip. 489 00:52:12,963 --> 00:52:14,760 With her own changed body, 490 00:52:14,898 --> 00:52:19,665 a female sweeps out a gravel nest and releases her eggs. 491 00:52:27,210 --> 00:52:30,941 A male offers his swirl of milt. 492 00:52:41,892 --> 00:52:45,658 This grotesque body change is still a mystery. 493 00:52:46,596 --> 00:52:51,590 Does the male's hooked face help in jousting matches with rivals? 494 00:52:53,570 --> 00:52:56,471 Does the female choose a male for his new colors, 495 00:52:56,606 --> 00:53:01,976 a sexy but reckless display that draws the fire of predators? 496 00:53:02,112 --> 00:53:06,276 All that's certain is that this change is the creature's last. 497 00:53:06,416 --> 00:53:09,908 And perhaps in death, the fiinal transformation, 498 00:53:10,053 --> 00:53:14,046 the parents offer their decaying bodies to feed the pools 499 00:53:14,191 --> 00:53:17,217 where the next generation will grow. 500 00:53:21,798 --> 00:53:26,201 The life of every creature is a journey of change. 501 00:53:27,804 --> 00:53:33,970 So too is the path of all life since the very dawn of living things. 502 00:53:42,986 --> 00:53:44,954 Though we may resist change, 503 00:53:45,088 --> 00:53:50,685 or wish to turn back the clock no one can tether time. 504 00:53:51,394 --> 00:53:53,919 We are all transformers, 505 00:53:54,064 --> 00:53:59,263 for the story of life is the story of change.