Eyewitness II; #103; Reptile

Presentation of this program was made possible by the Corporation for Public Broadcasting and by annual financial support from viewers like you. (intro music) Reptile: mysterious . Mythical. Monsterous. The name means things

that creep. And that's just what they've done, crawling and slithering into the corners of our imagination. They look like creatures from fiction, but with reptiles, fact is far stranger than any fiction. Reptiles come in four families: lizards and snakes, fascinating and foreboding. Turtles: slow and strong. Crocodilians: monsters of the waterways and the one and only tuatara,the living fossil. What is a reptile? All reptiles had scaly skin. It's thick and water-tight like a raincoat in reverse. It keeps the water in. Reptiles are cold blooded. They get their heat from basking in the sun, making them the original sun worshippers. In effect, they're solar powered. At the start of the day, all a reptile can do is just sit there, soaking up enough energy to get moving.

But it's a very efficient design. Since they get 80 percent of their energy from the sun, reptiles need far less energy to come from food. They can stay in one place rather than chasing after the food like warm blooded mammals. [insect buzzing] And what if they get too hot? Reptiles always find a way to cool down. They might hide under the sand, or clamber into the shade of a convenient rock. The crocodilian family gapes, just as dogs pant, to release excess body heat. And this creature goes into workout mode to stop the hot sand from burning its feet.

Reptiles come in all shapes and sizes. There are lizards that are larger than a human and others smaller than a beetle. There are six and a half thousand different types of reptiles, each sculpted by the fine art of adaptation to fit its environment perfectly. Like the moloch or thorny devil, a threatening vicious monster? Only on the outside. It's a member of the largest reptile family, the lizards, and lives in the desert where those spines do more than just deter predators. They collect dew for the animal to drink. Or the basilisk, named after a mythical medieval beast that could kill with a single look. This animal is harmless. It's light and athletic and has frills on its feet which help it literally to walk on water. That's why it's

sometimes called the Jesus Christ lizard. Geckos have adapted brilliantly. Their feet are like suckers covered in millions of tiny hairs that will grip almost anything from any angle. The turtle has a unique adaptation: its backbone has become a shell. It's actually part of the animal's body. And when that body belongs to a giant tortoise that's a big, tough, and heavy shift. It's so tough, and giant tortoises have such strong muscles that, if it would let you, you could use one as a jack. Yes, these creatures that can live for over a hundred years could support more than a ton of metal. Maybe that's why of thousands of years ago people in Asia Minor believed that the earth was held up by a tortoise.

Sea turtles have adapted to the oceans wonderfully. They can stay underwater for over three weeks at a time without taking a single breath (not something to try in your local pool). But when they move, they really move, migrating thousands of miles. The reptile family closest to the sea dragons of myth are the crocodilians, embracing alligators, caymans and of course crocodiles. With their huge smiling jaws and watery eyes they're as old as the dinosaurs and perfectly adapted to life in the rivers. Their tails are their motors. Their feet are their rudders. Their skin is an iron hull. And when they move they strike like lightning. [splashing] A fully grown crocodile can lie submerged for well over an hour waiting for prey. When they make a kill, they can't chew. So they have to twist and literally tear the meat

off the carcass. Vicious? Deadly? Certainly. [chirping] But these killer jaws can also gently cradle a baby. [chirping] Crocodilians are one of the few reptiles that look after their young, and with protection like this, who would dare snatch a baby from the jaws of its mother? In fact, it's the jaws that show the difference between a crocodile and an alligator. An alligator has a more rounded snout, and its front teeth stick out. Alligators are smaller, too, and are only found in China and America. Their appetites are smaller too, unlike the largest crocodile, the saltwater, which will eat almost anything. The people in Papua New Guinea believe the crocodile is the Creator of All Things. Young men are swallowed up and regurgitated as adults.

Hence these teeth marks on their backs. Even their canoes are carved crocodiles carrying people, just as crocodilians carry their babies on their backs. The ancient Egyptians relied on the Nile for their lives. It was the source of all their prosperity, but swimming in the river of wealth was the crocodile, a deadly reminder that the gods were still in charge. So they worshipped crocodiles and gave Sobek, their god of fertility, the head of a crocodile. The largest reptile family is made up of lizards and snakes. Snakes evolved from lizards, appearing after millions of years of changing shape and losing their legs. A snake is long on length and short on width. Its internal organs have been

rearranged like carriages on a train: windpipe, heart, small left lung, long right lung, long liver, long stomach, long intestines, long kidney. And holding it all in: a long, long spinal cord with ribcage. The The biggest snakes can have 400 vertebrae, each with its own pair of ribs. And each of these helps with locomotion. Some snakes seem to slither, but the Sidewinder truly has a style all its own. It steps across the baking sand with only two parts of its body touching the ground at any time. [drum music] Snakes don't just use their muscles to walk. Many use them to squeeze their prey

to death by constriction. They do this by literally crushing their prey, tightening their hold with every breath the victim takes, slowly but surely suffocating it. They're so alien that snakes have a special place in mythology, from ancient Greece, where serpents were sent to kill Laocoön and his sons, to the fearsome snake pits of modern adventure films. But the classic image of terror is the Greek Medusa, a Gorgon with snakes for hair. Even after she was decapitated by Perseus, just one look was still enough to turn anyone to stone. [hissing] In the Bible, the snake is the symbol of evil, tempting Eve with the apple. Even a snake's forked tongue seems to carry a threat, something Hollywood has given lip service to in its movie monsters. It's not

real of course. But it is great entertainment for lounge lizards everywhere. What the tongue is doing isn't vicious or threatening at all. It's just tasting the air, gathering information for a sensor in the roof of the mouth called Jacobson's organ. It's like smelling, but a lot more accurate. [bugs chirping] Lizards also use their tongues in various ways, like cleaning their eyes. Very useful as many don't have eyelids for blinking. [tongue noises] But when it comes to tongues, chameleons can silence any challenge, for their tongues are like an extra limb, longer than their body, and they can use them to catch prey. [birds chirping] They have eyes that move independently so that they can look in two directions at once. If humans tried this, they'd just go cross-eyed. For a chameleon, it means 100

percent accurate tracking of prey, making the tongue the reptile equivalent of a guided missile. [orchestral music] Perhaps what chameleons are most famous for is their ability to change color. One chameleon can be any or all of these colors. But reptiles don't actually see color very well. They see movement. A snake charmer's music isn't charming to the snake. It's too high pitched for any snake to hear. The snake is really swaying to the movement of the pipe. It would strike, if the pipe would stay still. Even without the pipe the snake is still mesmerized by movement. Reptiles wear coats of many colors, although they themselves can't see them. [mysterious music] Color can serve as a reptile's first line of defense,

(music) provided it remains in its color-coordinated natural habitat. (music) Camouflage works to conceal reptiles from their prey, helping them to make that vital strike. [hissing] Sometimes it's better for all concerned if everyone knows who's who and what's where. A rattlesnake rattles to say, "Don't tread on me." And peccaries know better than to tangle with a rattler. [snake ratting] [pig grunting] A coral snake doesn't have to shout to be noticed. Its color announces its deadly poison. Red, yellow, and black are nature's primary warning colors.

But some appearances can be deceptive. This frilled lizard looks vicious and threatening, but it's all bluff. Behind the skin and bone frill is a reptile far more likely to turn tail and run. The armadillo lizard just puts its tail in its mouth, making it very difficult to eat. Some tails are a bit too long for that, though. It's when it comes to mating, however, that reptiles display some of their most bizarre characteristics. [upbeat percussive music] (music) Ploughshare tortoises

jousting over a female resemble a pair of tanks, aggressive characters coming out of their usual shells. [armored tank engine] [turtle grunts] Reptiles were the first animals to leave the water for good and stay on land, but they only accomplished this giant leap by taking a bit of the water with them. So wherever a reptile lived, however dry it was, it still had some water for its very young babies, a drop of water and a bag of food, and a casing with very tiny holes so air could get in without water leaking out. We're talking about eggs. Reptiles were the first animals to lay eggs with shells. They invaded the land and could live anywhere,

thanks to eggs. But that doesn't mean growing up is easy for a young reptile. Far from it. From the thousands of eggs laid here only five males will will survive to mate, and five females will live the 30 years it takes to mature, and return to lay eggs of their own. Because these babies are easy prey. (music) (music) On a group of islands off New Zealand, the fourth and smallest reptile family, the

tuatara, had few predators to contend with. There are only three species of tuatara, and they bear the closest resemblance to ancient reptiles. Now they're in danger of becoming extinct, Because almost a thousand years ago, humans arrived, bringing animals that were new to the islands, including predators that could invade tuatara burrows and eat their eggs. Most species adapt over millions of years to life with predators. Not so with tuataras. So this living fossil with a vestigal third eye on the top of its head to sense light and a metabolism so slow they can go up to 60 minutes without breathing is in danger of breathing its last, and vanishing from our world. One animal that still hasn't appeared in New Zealand is the snake.

They've only been on the earth as long as the mammals and birds, almost as though they evolved specifically to hunt them. They certainly have a special technique for dealing with bird eggs. The snakes jaws are expandable to fit the egg in. There is a muscle to help swallow the egg. There are special spikes on the inside of the spine to break the egg so the tasty contents can be eaten, and the crushed empty shell regurgitated. Finally the jaw is put back together with a lazy yawn. [cracking] [insect buzzing] Fangs: the hypodermic needles of the reptile world. In fact, less than a quarter of the world's snake species have venom that is harmful to people, and many of these are now milked for their poison to create anti-venom. [dripping] It's injected into horses, where immunity builds up in the blood, which is then used for

serum against the snake bite. Nevertheless there are still 30 to 40 thousand human deaths each year from snake bites. One of the most venomous snakes of all is the sea snake. This one isn't tying itself in knots. It's rubbing against itself to shed or slough its skin. Reptiles grow out of their skins, shedding it like a garment that no longer fits. And because of a snake's shape, all it has to do when it changes skin is just crawl out of the old one. This leaves behind a ghostly double. It looks as though the snake has been reborn. so snakes have become the symbol of eternity. [birds chirping] The Hindu god Vishnu lies in heaven in the coils of the eternal serpent. [digiridoo music] The Australian aborigines believe that the mother and father of all creation, including

humans, is a snake. In the West, the sign of Asclepius, the Greek god of medicine, and the modern symbol of health and healing, is a staff with a snake wound around it. [ambulance sirens] But reptiles can't be contained by myths and symbols. They're larger than life. The komodo dragon, a real live dragon, is the largest lizard in the world. It's 13 feet long, weighs 300 pounds, and is genuinely fierce. Its saliva is toxic, so it can kill just by biting and then waiting for its prey to drop, exhausted from infected wounds. But it usually feeds on animals that are already dead. [snorting] The alligator snapping turtle, also the stuff of nightmares.

It can weigh as much as a grown man and eats anything it can get. The alligator snapper lies disguised on the riverbed, mouth open, its worm-like tongue luring unsuspecting prey. In parts of Europe they now lurk in ponds and streams. Whatever gets too near is snapped, and that can be anything, from a small fish to a human hand. [water flowing] The Chinese honored dragons as law-givers. In the Manchu dynasty everything used by the emperor was described in terms of a dragon. They even believed a dragon introduced the art of painting to China. The Constellation Draco was named after a dragon hovering in the heavens. Knights like St. George

fought dragons in legend, Hence their use as a symbol in heraldry. European mythology cast dragons as evil, fire-breathing monsters that roam the countryside, kidnapping maidens and hoarding great treasures, perhaps because the early Christians were eager to demonstrate their power over the natural world. It's just another one of our projected images. It's not humans that are most at risk from snakes. Lizards live the nightmare that, given the opportunity, a snake won't hesitate to make a meal of its reptilian cousin. [suspenseful music] (music) Yet, just when it seems all is lost,

some reptiles have one more twist, literally in their tail. Many lizards can shed their tail to evade capture. It's a final resort, but it means safety. It's just one more reason reptiles have survived so long. One more adaptation, one more way in which the truth about reptiles is stranger than the myth. [Eyewitness theme music] Presentation of this program was made possible by the Corporation for Public Broadcasting, and by annual

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