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The frog -

Wood frogs hibernate in winter by nearly freezing to death. As their heart rate slows, ice crystals form in the blood. Eventually as the weather warms up, this amazing creature starts breathing again as its tiny heart begins pounding.

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The Adélie penguin -

Common along the entire coast of the Antarctic continent, the Adélie penguin makes its nest out of pebbles and rocks, which helps protect eggs from the feet of stumbling neighbors and melting snow.

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The dragonfly -

Only two creatures on Earth have full 360-degree vision. One is the chameleon, the other the dragonfly. In fact, of all insects, the dragonfly has the largest eyes.

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The elephant -

Elephants can’t jump. Not surprising perhaps, given their bulk. But this gentle giant has weak lower leg muscles and inflexible ankles, so leaping anywhere is out of the question.

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The zebra -

Odd as it sounds, those conspicuous black and white stripes decorating a zebra's coat actually make it harder for potential predators to identify the animal at a distance. One theory is that the stripes mimic the long grass habitat that zebras prefer.

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The warbler -

The golden-winged warbler has been known to predict a storm days before it occurs.

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The giraffe -

Not only is a giraffe's tongue long and thick, it's black and purple too. This is probably due to the extra melanin present in giraffes' mouth organs. Melanin acts as a natural sunscreen and helps protect the tongue, which is used all day to gather plants and leaves.

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The wombat -

Wombats are the only animals in the world that produce cube-shaped poop. The Australian marsupials excrete the odd-looking scat because it's sculptured that way as it passes through the animal's irregularly-shaped and elastic intestines.

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The quokka -

A resident of Rottnest Island in western Australia, these furry marsupials can survive for up to a full month without a drop of water. They keep hydrated by munching on leaves and vegetation that is packed with moisture.

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The jellyfish -

For Turritopsis nutricula, immortality is a way of life. This 4.5 mm (0.2 in) jellyfish never dies. Instead, it shrinks its body, retracts its tentacles, and sinks to the bottom of the ocean floor. There it starts its life cycle all over again.

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The toucan -

These amazing and radiant birds indulge in a mating ritual whereby each toss fruit back and forth with their beaks in a gesture of caring and sharing.

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The koala -

These cute marsupials from Australia munch exclusively on eucalyptus leaves. But the truly unique aspect about this doll-sized animal is that it has fingerprints that are almost identical to human ones.

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The shark -

Most sharks must swim constantly in order to keep oxygen-rich water flowing over their gills. Others are able to pass water through their respiratory system by a pumping motion of their pharynx. These are the ones you see resting on the seafloor while still breathing.

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The emperor penguin -

How do emperor penguins achieve such momentum when launching themselves out of the ocean and onto dry land? The trick is the release of air bubbles under their feathers as they swim towards the shore. This cuts the drag on their bodies and propels them faster through the water.

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The sea otter -

An endangered species, sea otters are playful and sociable creatures. They have a habit of holding paws with each other when sleeping to keep from drifting out to sea—especially cute when mother and pup are seen in a warm embrace.

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The flamingo -

Get this: flamingos aren't pink. They're actually born a dull gray. What gives the birds their distinctive hue is their diet of shrimp and blue-green algae, which contain a natural dye. In time this causes their feathers to turn pink.

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The lemur -

This threatened Madagascar resident is the only primate besides humans that can have blue eyes, which both sexes are endowed with.

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The hippopotamus -

The African sun can be merciless and, like other animals, the hippo has its own unique way of dealing with it. The lumbering herbivores have their own cooling system, an oily secretion that evaporates as it dries thus lowering the hippo's temperature. The substance is known as "blood sweat" because it appears red in the sunlight.

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The cat -

Ever wondered why your cat doesn't have a sweet tooth? It's because all domesticated felines lack sweet sensors on their tongues.

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The leech -

These predatory worms were used in medicine from ancient times until the 19th century to draw blood from patients. Nowadays they mostly draw gasps of disgust, not least for their three separate jaws lined with 100 teeth each!

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The vulture -

Some vultures are known to vomit when threatened or approached. This isn't a defensive gesture but rather to lighten their stomach load to take off. In addition, the expelled meal residue may distract a predator, allowing the bird to escape.

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The goat -

One of the oldest domesticated species of animal, goats have an unusual characteristic: they have no teeth in their upper jaw. Instead, they have a fleshy palate called a dental pad that helps them rip and tear their food!

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The cow -

Bovines like their buddies. The more friends a cow has, the less stressful its life. That's why you'll often see them herded together.

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The caddisfly -

While adult caddisflies are terrestrial, their larvae are aquatic. So these industrious insects create semi-submersible retreats using silk to meld together tiny bits of river detritus (pebbles, pine needles, grass strands, etc.), which they enlarge as they grow bigger.

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The giant panda -

An endangered species, pandas feed almost exclusively on bamboo. Almost. As omnivores, these black and white sensations are known to occasionally snack on small animals and fish.

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The hummingbird -

These tiny and exotic creatures are the only birds in the world that can fly backwards.

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The raccoon -

On occasion, raccoons are surprisingly well mannered and sophisticated eaters. They've been observed dunking their food in water as if to give it a quick rinse before tucking in.

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The octopus -

These soft-bodied, eight-limbed denizens of the deep are among the most intelligent and behaviorally diverse of all invertebrates. And that's probably because they have nine brains. And that slick maneuverability? Well that's fueled by not one but three hearts.

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The rhinoceros -

Contrary to popular belief, rhino horn is not made out of bone. It's made of keratin, the same material that comprises human hair and fingernails. What is true, however, is that these armor-plated herbivores are among some of the most critically endangered animals on Earth.

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The Myanmar snub-nosed monkey -

This critically endangered animal is known as the sneezing monkey apparently because its upturned nose gets water in it when it rains, which the monkey sneezes out.

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The sheep -

Sheep have weird eyes, don't they? But don't laugh. These ubiquitous herbivores have a distinct advantage over all of us in that their rectangular pupils afford them incredible peripheral vision, anywhere between 270 and 320 degrees.

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The dog -

How does your dog know when it's time for walks? Well, the average canine has an innate sense of when things should happen. This means it's clued in on regularly scheduled walks and mealtimes, and will remind you if you forget.

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The snail -

Snail slime is known for its anti-aging properties. It helps to stimulate the formation of collagen and elastin, soothe and protect skin from free radicals, repair damaged tissues, and restore hydration.

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The crow -

Crows are clever. They are intelligent birds with an innate ability to solve simple problems quickly, like using their beaks to crack the shells of nuts against concrete. Or, wait for it, laying nuts on a road so vehicles can run over them, effectively doing the job for them!

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The tiger -

The stripes on every tiger are as unique as individual finger prints. Indeed, were you to shave one of these beautiful big cats, its coat pattern would still be visible as stubble. Of course, tigers are best left alone to be admired from a distance.

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The honeybee -

Drone and worker bees each have their own personalities and traits that cause them to excel at the jobs they're best suited to.

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The manatee -

The much-maligned manatee, also known as the sea cow, is a vegetarian and needs to eat 10% of its body weight every day.

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The dolphin -

Dolphins are among the most intelligent animals on the planet, and no wonder! These delightful marine mammals are able to call each other by "name" by mimicking the signature whistle of the dolphin they're seeking.

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The rabbit -

Rabbits have long ears for a purpose, and can rotate them 270 degrees in order to detect sounds, some from as far as 3.5 km (nearly 2 mi) off. The elongated appendages also work as fans in hot weather, shedding heat so that bunnies can stay cool in the summer.

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The butterfly -

Butterflies feed primarily on nectar from flowers by using their tube-like tongues called probosces to suck in the sugar-rich liquid. But they taste with their feet, as their taste receptors are located there.

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The bearded dragon -

These ferocious-sounding reptiles are, in fact, real sweethearts. They'll bob their heads and wave to each other as a sign of recognition, in a manner reminiscent of human acknowledgment.

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The camel -

Did you know that when the camel exhales, water vapor becomes trapped in their nostrils and is reabsorbed into the body as a means to conserve water? No wonder they're nicknamed the "ships of the desert."

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The platypus -

One of the few species of venomous animals, the male platypus has a spur on the hind foot that delivers a venom capable of causing severe pain to humans, though not enough to kill.

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The narwhal -

Romantically named the "unicorn of the sea," the narwhal's tusk is, in fact, a narrow, protruding tooth. Mind you, it's only the males that are this long in the tooth.

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The grizzly bear -

Grizzlies are humpbacks. Look at this photograph: the hump is where a mass of muscles attach to the bear's backbone and give the animal additional strength for digging in search of food and when making a den.

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The honey badger -

One of the world's most fearless creatures has a fearsome appetite, including a taste for poisonous snakes. Fed toxic critters like scorpions by their moms from a young age, these mammals grow up with an immunity from nasty venom.

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The hyena -

Despite their dog-like appearance and fearsome reputation as pack hunters, hyenas are more closely related to cats. Their scientific classification puts them in the feliformia order—"cat-like" carnivores.

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The peacock -

We all call them peacocks but, in fact, "peacock" only describes the males; females are known as peahens. Collectively, these birds are considered peafowl.

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The chimpanzee -

Chimps like a drink. Their favorite is fermented palm sap, which they gather up using crushed leaves that act as a sponge. And yes, knocked back in sufficient quantities, this intoxicating treat can leave chimps drunk and thick-headed.

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The sloth -

Did you know that sloths can swim? Once in water, they adopt a breaststroke technique and swim four times as fast as they can move.

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The whale -

Among the largest creatures on the planet, whales use up a lot of energy just swimming. But how do these graceful mammals sleep, and how do they stay alert to danger while doing so? Scientists have discovered that cetaceans slumber with one eye open and only half of their brain awake. This phenomenon is called unihemispheric slow-wave sleep.

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The kangaroo -

At its fastest, a kangaroo can hop, skip, and jump up to an incredible 71 km/h (44 mph). But it can’t walk backwards! The arrangement of their powerful rear feet and oversized tails simply won’t allow it to.

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The bat -

Bats are associated with darkness, death, witchcraft, and malevolence. But don't knock these winged mammals. Some bat species actually do us a favor by gobbling up 1,000 mosquitoes in a single hour.

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The polar bear -

These beautiful but vulnerable beasts are for the most part solitary. However, when getting together they adopt a unique meet and greet technique by gently touching or "mouthing" each other around the face and neck.

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The housefly -

The housefly flaps its wings an astonishing 190 times per second. That creates the buzzing sound that the human ear interprets as a frequency of 200 Hertz, or a pitch along the F major scale.

See also: Earth's best destinations to see wildlife.

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