- [voiceover] today on animal science. the siberian tiger is the biggest cat in the world. it takes down large prey with its five inch long canine teeth. (roar) and the american badger's sharp front claws make it one of the best burrowers. plus, the toad may not look pretty, but it goes through one of the most incredible transformations on earth. today, we'll take a look at the most amazing creatures from all parts of the globe.

welcome to the fascinating world of animal science. there are three basic types of environments in the world. the sea. the sky. and the land. for most terrestrial animals, traveling from place to place on foot, or on hoof, is essential for survival. the giraffe is the tallest land animal on earth. in arabic, its name means "fast walker." and with legs six feet long, it doesn't take much effort for the giraffe to move across the african savannah. flightless birds, like this ostrich, use their strong legs to escape predators

and deliver lethal kicks. how would you like to get a face full of these feet? kangaroos don't run, they hop, which works quite well. this springy marsupial can cover 20 feet in a single bound. in southeast asia, the orangutan's short legs make walking a bit cumbersome. but with a wingspan that stretches seven feet, it can swing through trees with the greatest of ease. we humans aren't built for tree climbing, but our long, powerful legs enable us to run great distances. and sprint up to 27 miles per hour. we can also leap more than three times our height.

but how does our ability to run and jump compare to other animals? well there's one sure fire way to find out. it's time for our animal science experiment of the week. our experiment features two participants. one is a college long jumper. the other is a belgian shepherd dog named rocket. each will sprint down the runway and then leap as far as possible into the pool. whoever leaps the furthest, wins. first up, jerry the jet. - [voiceover] go! - [voiceover] jerry leaps about 20 1/2 feet.

next up, rocket the dog. - [voiceover] ready, go! - [voiceover] rocket outdoes jerry with a leap of 23 1/2 feet. how does he do it? well, the most important factor to a good jump is good speed prior to the jump. this is where rocket has a major advantage. on average, a dog can run about twice as fast as a human. in our animal science instant replay, we can also see a subtle difference in jump technique. rocket the dog uses his two hind legs simultaneously to propel his body into the air. jerry the jet only uses one.

no wonder the dog has an advantage. two legs are definitely better than one. when we return, you'll find out how badgers dig tunnels up to 13 feet deep. and why the woodpecker spends so much time drilling through trees. right here on animal science.

- [voiceover] in the animal kingdom, safety is never a guarantee. most creatures must fight for survival on a daily basis. for some, the means of protection is simply a hole in the ground.

if you're on a sandy beach, you just might get lucky and spot an elusive creature called the ghost crab. they're known for their habit of disappearing into burrows. - when it's very hot during the day they'll retreat to the burrow, where it stays cool. when it's very cold at night, they'll stay in there, especially in the winter time, they'll stay in there for that period of time. - [voiceover] ghost crabs' eyes sit on stalks above its head. this helps it detect predators coming from any direction. and if threatened, it will simply vanish, like a ghost. (ghostly laughter) the woodpecker may not be the biggest creature in the world, but it packs a powerful punch.

(woodpecker pecking) these birds can hammer into trees at a rate of 20 times per second. (banging) each strike generates a force of up to 1,200 g's. that's more than 10 times the force a human experiences in a high-speed car crash. (crash) (pecking) most of the woodpecker's power comes from its feet. - most birds have three toes in front and one in the back. woodpeckers have two toes in front, two toes in the back. so that way as they're thrusting their head back and forth against the tree, they can hold on to the side of the tree with a much better grip. - [voiceover] and that's not all. woodpeckers have powerful neck and jaw muscles. and their skulls are reinforced with soft cartilage, which helps absorb impact.

(pecking) the result of all this drilling is a freshly-made burrow. the woodpecker will use the burrow to raise its chicks. so if you hear a lot of noisy hammering going on outside your bedroom window, don't get mad at the woodpecker. it's just tryin' to make a livin'. one of the fiercest burrowing predators in the united states is the american badger. the badger feasts on other burrowing animals, such as ground squirrels, and prairie dogs. and it has developed some unique ways of finding its prey. - one of the cool things that american badgers' do is, a lot of 'em will form a partnership with a coyote.

(howling) the reason why they form a partnership with a coyote is a coyote has a very good sense of smell, and a badger doesn't. so the coyote kinda smells where the animal is, and the badger digs it out, and then they both share. - [voiceover] with long claws, and short, powerful legs, the badger can barrel through the ground like a mini bulldozer. so we're giving this badger the animal science award (cheering) for being the best burrower. come on badger, take a bow. next, find out why the siberian tiger is the world's biggest cat, and how the snowshoe hare's giant hind feet help it navigate through deep snow. right here on animal science.

- [voiceover] promotional considerations paid for by the following. senokot® tablets provide -it's the senokot® tablets c$50,000 get relief quiz. overnight relief from occasional constipation. true! true! win every day at senokotquiz.com - [voiceover] the long arctic winter spells doom for many creatures. those fortunate enough to survive, do so with talent, guts, and willpower. you see, winter survival is like running a marathon.

but in the animal world, there's no prize for first place, only the satisfaction of knowing that spring is just around the corner. the siberian tiger is the largest and rarest of all the big cats. thanks to its thick fur coat, it is able to withstand temperatures of 50 below in the dead of winter. the siberian tiger is sometimes confused with the bengal tiger of india. but when you compare them side-by-side, it's clear that the siberian is larger. - [voiceover] another difference between siberian tigers and bengal tigers is that there is a layer of belly fat that are found in siberian tigers.

the belly fat actually allows siberian tigers to be able to survive if they can't find prey. - [voiceover] unlike the siberian tiger, the bobcat has adapted to a variety of environments. from scorching hot deserts to the frigid canadian wilderness. - the cool thing about them is that they are spread pretty much all over north america. so you don't see them that often, but when you see them, you see like the really intense-looking house cat that might be a bobcat in your back yard. - [voiceover] the bobcat is only about twice the size of your average house cat. and it gets its name from its short, bobbed tail. in warmer climates, it has shorter fur. but up north, bobcats are protected by one of the densest coats in the animal kingdom.

bobcats feed mainly on small mammals and birds. but their favorite snack is a furry little critter that hops about in the snow. it's called the snowshoe hare. compared to other animals of similar size, the snowshoe hare has enormous hind feet. this makes moving on the snow surface a lot easier. always on the lookout for predators, the snowshoe hare's best means of defense is its ability to blend in. - snowshoe hares have what's called seasonal coloration. in the winter time they have this beautiful, thick, white coat of fur to help them to camouflage and blend in and hide with the snow. in the summertime, they will lose that thick, white coat of fur and they'll actually get a brown coat instead.

- [voiceover] this brownish coat helps the snowshoe hare blend into the lush summer wilderness. just another example of how nature has equipped every animal with the tools it needs for survival. when we return, from tadpole to toadlet. this creature undergoes one of the most astonishing transformations you'll ever see. right here on animal science.

- [voiceover] do you know the name of this small, wart-covered amphibian? no, it may not be the prettiest animal in the world, but it undergoes one of the most astonishing physical transformations on earth.

a toad is actually a type of frog. but it has some distinct differences. unlike frogs, who spend most of their time in or near the water, toads spend most of their lives on land. that's because their skin is tougher and doesn't need to be kept as moist. toads also have warts all over their body, which actually serve an important purpose. - the warts on the skin seem to be for camouflage. they're usually sort of dark brownish color, and they'll be like rippling and spotting patterns which allow 'em to blend in. and then some of the warting is associated sometimes with different types of glands that produce venoms and poisons and things like this. (frog ribbeting) - [voiceover] and what about the rumor

that touching a toad will give you warts? - you cannot get warts from handling a toad. that's an old wive's tale. that is just complete nonsense. - [voiceover] okay then. the life cycle of a toad is fascinating. take, for example, the american toad, during spring, the male will make a loud noise called a trill. (trilling sounds) - as they inflate a sac, they also make the sound. it's basically a mating call. they're just calling for mates. (trilling sounds) a loud trill can be heard by many females. it'll often decide in the female's mind what his position is with respect to other males and all that sort of thing. - [voiceover] when the male finds his mate, he will latch on to the female's back. scientists call this embrace an amplexus.

but we think it looks more like a good, old-fashioned piggy-back ride. the female toad will then produce a string of eggs which hatch into these little critters called tadpoles. tadpoles are like tiny fish, equipped with gills for breathing, and a tail for swimming. they soon morph into something quite different. - as a tadpole gets closer to maturing, legs will stat to come out, the tail will start to disappear because it sort of self-destructs as time goes by, and the four limbs start to grow out and they lose the gills and eventually come out on land as a fully-formed land-dwelling animal. - [voiceover] these newly-formed terrestrial animals are called toadlets. pretty cute, huh? you could fit several of them on the head of a penny.

as these toads get bigger, they'll live on land for the next year, only returning to the water when it's time to mate. then the life cycle starts all over again. keep on trillin'. (trilling sounds) and trillin'. (trilling sounds) okay! when we return, take the animal science pop quiz and find out how much you really know about animals. right here on animal science.

- [voiceover] promotional considerations paid for by the following.

- [voiceover] and now it's time for the animal science pop quiz. ready, get set, go! question one. how long can an alligator live? 25 years. 50 years. or 100 years? it's c, 100 years. these gigantic reptiles are said to be immune to cancer. question two. what was the first bagpipe made from? the liver of a sheep.

(sheep bleating) the heart of a kangaroo. (hopping sounds) or the bladder of a cow? (mooing) it's a, the liver of a sheep. okay, final question. which of these animals cannot jump? the bison. rhinoceros. or elephant? it's c, the elephant. that's all for today, folks. we hope you got an a plus. from animal science, see ya next time. (elephant trumpeting)

we're talking college hoops this week on sports stars of tomorrrow... the season is about to tip off, and we're getting you ready with stories on some of the new faces for this season.... which freshmen are going to impact the national title chase? the answers are coming up next... (show open) welcome to our college basketbape