Eyewitness II; #110; Amphibian

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Creatures that live in water and on land. Animals that are born like fish but grow legs and walk. Ugly creatures that inspire legends of beauty Amphibians have fascinated us throughout history. Ancient Egyptians believed frogs were divine and that men and women were made by the goddess Hecate who had the head of a frog. Is it the human quality of frogs and toads which have led us to celebrate them in picture book and fairy tales? Or is it because they provide a clue to the story of evolution from water to land. The amphibian leads a double life.

It starts out in the water and becomes a creature living on the land - ambi bio's both sides of life. From swimming with fins to running with legs. The journey of evolution itself - the journey that has brought every one of us here and that same transformation is happening now many times over for the process that has taken land animals millions of years, these creatures accomplish in 12 weeks. It happens with almost every type of amphibian - those that have tails - the salamanders, the newts, the sirens. With the rarely seen Cecelia and with the largest group of all - frogs and toads. In all there are three and a half thousand amphibian species measuring anything from a baby's fingernail to the length of a man's arm and living anywhere from thirteen thousand feet up in the snowy peaks of the Andes to tropical rain

forests, to desert scorched by heat. Nine out of 10 amphibians are either frogs or toads. But which is which? The toad skin is dry and nobbly but despite the superstitions it doesn't give you warts. This skin, moist and smooth, belongs to the frog. For thousands of years the frog has been a symbol of fertility. The toad with poison glands behind each eye has long been associated with evil and witchcraft. In many ways frogs and toads are alike. They constantly pulsate their throats to pump air through their lungs and they both have strong back legs. But while toads walk frogs jump literally making a leap of faith as they close their eyes before takeoff. Some frogs can jump up to 36 times their own length , the equivalent

of a boy jumping 50 yards in one leap. Their jumping skills have catapulted some frogs to stardom filling theaters. The celebrated Croakers College in California not only trains frogs to jump. It even has a graduation day. Champion jumper Jellybean was owned by Ronald Reagan before he leapt to the White House. All amphibians have one thing in common - their porous skin. Most animal skins are designed to prevent the loss of water. But amphibian skin it is far more prone to leak. There's no problem when amphibians are in water where there is plenty of moisture inside and out. The trouble comes when they go on land. Their skin is like a sieve. For this reason amphibians rarely wander far from water. But how do frogs survive in the desert? In a word - patience. The

Cyclarona frog builds itself a transparent bag and waits as long as seven years for the rains to arrive. When the time finally comes for this amphibian Rip Van Winkle to crawl out of the sack the bag provides the frog's first meal. The wax frog which lives high in the trees retains moisture in dry weather by producing wax from its skin and coating itself. The red eyed tree frog prevents the loss of moisture on a hot day by curling up in the shade. Having traded the watery confines of the egg for the pond, the tadpole soon loses its feathery gills and grows lungs. Sight in hearing are developing too. Hearing is acute in frogs and toads and is used to

find a mate. The male Koki frog has a two-part call but the females hear only the high pitched mating part whereas other males hear only the lower warning tone. Good hearing is vital to the American bullfrog. The males are aggressive - constantly listening for competitors. Their huge and sensitive ears are twice the size of their eyes. Because amphibian eyesight has adapted to many habitats, their eyeballs come in all shapes and sizes. For night vision eyes come in cat-like slits both horizontal and vertical. There are even the square pupils and heart shaped ones. Amphibian eyes come in a wide range of colors. Yet they only see in two colors - black and white.

This predator has the ability to see in ultraviolet - very little escapes its keen eye sight. But its prey has a trick up its sleeve. The frog's skin reflects the same amount of ultraviolet light as the leaf it sitting on - so the frog and plant become indistinguishable - a disappearing act. All the snake sees is an empty leaf. (music) In this case the frog's adaptation wins the day. On the evolutionary road to survival the amphibian has adorned itself in many

colors. It can blend in with the greenish browns of moss or gleem chocolate brown in the bed of mud. It will spread itself weed-like at the bottom of a pond or simply be a leaf. While some amphibians disappear to survive, others go on display. The bright hues of a poison dart frog are a warning much like the colors found in the headdresses of Native Americans. Amphibian colors are nature's way of saying: don't dine on me. The Golden Dart is the most poisonous frog on earth. The skin of one

frog could kill one thousand people - one of nature's most deadly poisons. After six weeks the tadpole grows what will allow it to leave the water - legs. 400 million years ago some fish were making the move from water to land. The evolution of fins to legs had begun. 400 years ago as Shakespeare's witches stirred their steaming kettle People knew well the evil ingredients of their brew. By tradition the toad is the first and key ingredient in any spell. The powerful poison of some amphibians has long been recognized as a weapon. The Choco Indians use it to poison their blow pipe darts But the skin of amphibians can also be used in the battle against illness.

In 1986 an entire new class of antibiotics was found in the skin of an African clawed frog. They were named meganins after the Hebrew word for shields and even more recently a painkiller with 200 times the power of morphine has been discovered in the skin of a frog. To survive in the world of skillful hunters such as bats, spiders, snakes, birds and fish, amphibians have devised clever defenses. In preparation for his battles. Toad of Toad Hall is famous for puffing himself up. But upon seeing the enemy he often thinks better of it. Others use bluff with more success. A threatening noise backed up by a fearsome face persuades a possum of dying elsewhere.

Unlike the blustering Mr. Toad some really do puff themselves up. And in a world where size is often perceived as power the bluff often works. The salamander can play dead or threaten by flashing its brilliant yellow underside. Their fiery color wasn't the only reason the Greeks called them fire lizards. Having witnessed salamanders running from burning logs ancient people believed the Salamander was born in fire and lived in flame. It's impossible of course but living in ice is not. Some amphibians can survive in temperatures well below freezing. In winter, two thirds of the water in a Canadian gray tree frog turns to ice. The heart

stops beating yet it remains alive by producing its own antifreeze which prevents it from freezing solid. With the spring thaw, the frog emerges from cold storage. The organs start working again. Muscles begin moving. The frog has survived the long Canadian winter and leaps into the new season. Although frozen frogs have never appeared on supermarket shelves, canned frogs have. In the 50's they were all the rage. Whereas humans usually prefer food that's no longer alive, amphibians prefer food that still moving. If it's got a pulse, it's lunch. All amphibians have a sticky tongue attached in the front of their mouth extending its

reach as it lashes out. An amphibian's swallowing blink not only protects the eyes but pushes the eyeballs back helping to force the food down the throat. Some amphibians have huge appetites. One African bullfrog devoured 14 baby Cobras at one sitting - the equivalent of a man swallowing two dozen newborn lambs including the woolen wrapper. After nine weeks in the pond the miniature frog has lungs that gulp air from the surface and grows front legs. Each step of which transformation from a pond dweller to land animal echoes millions of years of evolution. There is one Salamander that changes with the weather. When water is plentiful it has gills and lives underwater. But in times of drought it develops lungs taking a huge gulp of air from the

surface and it's gills disappear. With lungs and a body capable of life on land. Its metamorphosis is complete. Remaining at midpoint in evolution is the lungfish. Despite moving on to land 400 million years ago. It still moves with the s-wriggle of a fish. Salamanders use the s-motion to swim. So do newts when they crawl. While the frog with the webbing between its toes demonstrates perfectly the term frog kick. Above the water in the tree, it's the sticky pads on the tree frogs fingers and toes and it's large eyes which are crucial. And its color mimicking the green of the Lees. It even has a bright stripe on

its side to suggest a flash of sunlight. Yet water still remains essential even to the tree dweller. The tree frog builds its nest over water. When the tadpoles hatch they drop straight in. The red eyed tree frogs large eyes give it superb vision - an absolute must when it comes to snaring fast moving insects. [Bird sound] In the trees trees webbed feet can also come in handy. Spreading their feet like many parachutes, some frogs can glide. Why hop when you can fly? Clinging fingers, clammy skin, the warts of a toad - are these the characteristics that contribute to the human aversion to amphibians - an aversion we have expressed throughout the ages in fairy tale and film?

Sometimes more humorously than horrifically. The most well known example of the frog's maligned reputation is the tale of the prince trapped in a frog's body who needed the princess's kiss to set him free. In 16th century England, a woman found with a toad in her house would be instantly accused of witchcraft and put on trial. But why the toad? Do the warts of human aging and the toad's nobbly skin make the witch and the toad kindred spirits? Do they both possess uncanny powers of darkness? Since ancient times there have been countless stories splitting open without explanation to reveal a toad walled up within. Witchcraft? Sorcery? No - simply hibernation. To keep warm in

winter, toads will hide anywhere dark and damp. When they wake up in the spring they hit the road and migrate to their breeding grounds. Not all amphibians migrate, but salamanders do and newts as well. Perhaps the most well-known travelling amphibian is the toad. Woo hoo - hey! To reach their particular breeding ground which is also the place of their birth, toads will stop at nothing. They will cross highways, mountains, ignore other breeding grounds and travel up to 9 miles. How they actually find their way back to their home ponds Still remains a mystery. The greatest army of toads ever seen was not in the march of migration but in the

spread of cane toads in Australia brought in from America to rid sugarcane of pests. They quickly became pests themselves raiding gardens and even stealing food from pets. The skin secretion a Cane toads are highly hallucinogenic. For a time in California toad licking was popular in some circles. Kiss a frog and you might see a prince, lick a toad and who knows what you'll see. [Music] Nine weeks after birth the froglet's tail has served its purpose and shrinks in anticipation of the move to land. Having completed the migration, to the pond is full. The males arrive first and croak to attract females. [Frog croaking] The frog

the frog's croak. Is not as ancient peoples believed a strangled cry of a newborn. But it's the beginning of the process. They are the urgent calls of adults seeking a mate. One croak can carry well over half a mile and there are millions of them. [Croaks] Humans may have strange ways to attract a mate, but the amphibian world certainly has its share of peculiar partnering. Like Dracula the vampire salamander and slaves the female by biting her neck. But instead of sucking her blood, he injects an aphrodesiac. From that moment on she slavish me follows him until he fertilizes her

eggs. Most males however have no such tricks and since they outnumber the females by about five to one, the privilege of mating goes to the winner of the pond wrestling contest. In the amphibian world, egg laying can range from the single egg of the Cuban poison Erroll frog to the 35,000 eggs that one toad can lay in a year. [Croaking] Amphibian males can make caring fathers. The Syrian toad gently arranges the eggs on the female's back with a wooden coo bake for several months before hatching. Perhaps the most unusual adaptation is that of the male Darwin's frog. He takes the eggs into his mouth as soon as they show signs of life.

And inside his mouth they continue to grow. Until the tiny frog legs are ready to jump out. [Music] After 12 weeks, the frog leaves the pond. One small hop for the frog, one giant leap for evolution. Three hundred and fifty million years ago the first amphibian crossed this same barrier and populated the earth. By the time the Egyptians created the myth about a frog-headed goddess who sculpted humans, the other sculptor of life, evolution, had taken the basic material of amphibian and shaped reptiles, birds, mammals, and humans.

The Egyptians also believed that for all these were partially formed human In one respect, they were right. In evolutionary terms the amphibian anticipates the human embryo. The presentation of this program was made possible by the

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