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Not all Gecko lizards have eyelids. In fact, most geckos don’t have eyelids.

Some geckos, like the leopard gecko, have moveable eyelids that work like people’s eyelids. These geckos can blink, and they can close their eyelids when they sleep. They will lick their eyes but they do it to remove something that is irritating their eye.

But geckos with moveable eyelids are not the majority.

Most geckos do not have eyelids. What they have is a transparent covering that protects their eyes. The covering is disc-shaped and it is called a brille. When the lizard sheds its skin, it also sheds its brille. So there is a brief time when the gecko cannot blink and it also has trouble seeing as it sheds.

People and animals have eyelids that protect and help moisturize their eyes. When people blink, our eyelids whisk away debris and leave a film of moisture that keeps our eyes from drying out. And we can close our eyelids to help us sleep. But the primary purpose of our eyelids is to clean, protect, and moisturize our eyes.

For geckos with moveable eyelids, their eyelids function similar to ours. Their eyelids clean, protect, and moisturize their eyes.

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Most species of geckos throughout the world do not have eyelids. There are more than 1500 species of these. However, there are at least 18 species of geckos that do have eyelids, and these are also found around the earth.

The vast majority of geckos do not have eyelids and therefore are unable to blink. However, they do have a clear film over their eye, that acts as a kind of permanent unmovable barrier. This transparent film is called a spectacle.

Geckos have spectacular long tongues, that are really moist and sticky. The regularly lick their own eyes, and this keeps their eyes moist. In this way their tongue acts in the same ways as a human’s eyelid.

Most geckos are native to hot countries also, and this licking of their eyes also helps in keeping the eyes cool.

Having no eyelids causes quite a serious problem, in that geckos are not able to close their eyes. This problem is added to by the fact that the majority of geckos are nocturnal: they hunt at night, and sleep during the day.

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Geckos are reptiles and are found on all the continents except Antarctica. These colorful lizards have adapted to habitats from rain forests, to deserts, to cold mountain slopes.

Over a long period of time, geckos have developed special physical features to help them survive and avoid predators. Gecko tails serve many purposes. They help balance their weight as they climb branches, they act as fuel tanks to store fat, and as camouflage to help them disappear into their environment. Geckos are also able to shed their tails if a predator grabs them.

Most geckos are nocturnal, which means they are active at night, but day geckos are active during the day and nibble on insects, fruits, and flower nectar. Most geckos make noises such as chirping, barking, and clicking when they are defending their territory or attracting a mate.

Female geckos lay their eggs in leaves and bark. Most geckos don’t have movable eyelids and instead have one transparent eyelid which they keep clean by licking it with their tongues.

There are many species of geckos. Depending on the species, their endangered status can range from least concern to critically endangered.

Credit : National Geographic 

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Gecko, (suborder Gekkota), any of more than 1,000 species of lizards making up six families of the suborder Gekkota. Geckos are mostly small, usually nocturnal reptiles with a soft skin. They also possess a short stout body, a large head, and typically well-developed limbs. The ends of each limb are often equipped with digits possessing adhesive pads. Most of the species are 3 to 15 cm (1.2 to 6 inches) long, including tail length (about half the total). They have adapted to habitats ranging from deserts to jungles. Some species frequent human habitations, and most feed on insects.

Like snakes, most geckos have a clear protective covering over the eyes. The pupils of common nocturnal species are vertical and are often lobed in such a manner that they close to form four pinpoints. A gecko’s tail may be long and tapering, short and blunt, or even globular. The tail serves in many species as a storehouse of fat upon which the animal can draw during unfavourable conditions. The tail may also be extremely fragile and if detached is quickly regenerated in its original shape. Unlike other reptiles, most geckos have a voice, the call differing with the species and ranging from a feeble click or chirp to a shrill cackle or bark.

Most species are oviparous, the eggs being white and hard-shelled and usually laid beneath the bark of trees or attached to the underside of leaves. A few species in New Zealand give birth to live young.

Geckos are abundant throughout the warm areas of the world, and at least a few species occur on all continents except Antarctica. Geckos’ colours are usually drab, with grays, browns, and dirty whites predominating, though Phelsuma, a genus made up of the day geckos of Madagascar, is bright green and active in the daytime. The banded gecko (Coleonyx variegatus), the most widespread native North American species, grows to 15 cm (6 inches) and is pinkish to yellowish tan with darker bands and splotches. The tokay gecko (Gekko gecko), native to Southeast Asia, is the largest species, attaining a length of 25 to 35 cm (10 to 14 inches). It is gray with red and whitish spots and bands and is frequently sold in pet shops.

Credit : Britannica

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Geckos are colorful, nimble little lizards classified in reptilian family Gekkonidae. More than 2,000 species exist, inhabiting divergent habitats on every continent except Antarctica. Geckos are carnivorous, meaning the bulk of their diet consists of meat from other animals. Their teeth are adapted to their specific method of eating, as well as for hunting and self-defense.

Most geckos have rows of small, conical teeth lining the premaxilla and maxillary bones on the upper jaw and the dentary bone on the lower jaw. Depending on the species, the premaxilla has between nine and 13 teeth; the number of teeth on the other bones varies due to repeated tooth loss and regrowth. Upper jaws usually have more teeth than lower jaws. In total, geckos average between 50 and 100 teeth, with exceptions. For reasons unknown, the leaf-tailed gecko has more than 300 teeth, most likely the highest number of teeth possessed by any terrestrial vertebrate.

They may not use them to chew, but geckos utilize their teeth for other purposes. Self-defense is a necessary skill for small, vulnerable reptiles. They're generally peaceful by nature, but if provoked or threatened, geckos will bite humans, predators and each other. Males especially,, are prone to violent fights over territory and females. They also use their teeth during the shedding process. Geckos shed their skin several times a year. They use their teeth to pull the old skin from their bodies, typically consuming it, as it is full of healthy nutrients.

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There were eight tiger subspecies at one time, but three became extinct during the 20th century. Over the last 100 years, hunting and forest destruction have reduced tiger populations from hundreds of thousands of animals to perhaps fewer than 2,500. Tigers are hunted as trophies, and also for body parts that are used in traditional Chinese medicine. All five remaining tiger subspecies are at-risk, and many protection programs are in place.

Bengal tigers live in India and are sometimes called Indian tigers. They are the most common tiger and number about half of all wild tigers. Over many centuries they have become an important part of Indian tradition and lore.

Tigers live alone and aggressively scent-mark large territories to keep their rivals away. They are powerful nocturnal hunters that travel many miles to find buffalo, deer, wild pigs, and other large mammals. Tigers use their distinctive coats as camouflage (no two have exactly the same stripes). They lie in wait and creep close enough to attack their victims with a quick spring and a fatal pounce. A hungry tiger can eat as much as 60 pounds in one night, though they usually eat less.

Despite their fearsome reputation, most tigers avoid humans; however, a few do become dangerous maneaters. These animals are often sick and unable to hunt normally, or live in an area where their traditional prey has vanished.

Females give birth to litters of two to six cubs, which they raise with little or no help from the male. Cubs cannot hunt until they are 18 months old and remain with their mothers for two to three years, when they disperse to find their own territory.

Credit : National Geographic

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The Nile crocodile (Crocodylus niloticus) is a large crocodilian native to freshwater habitats in Africa, where it is present in 26 countries. Africa's largest crocodilian can reach a maximum size of about 20 feet and can weigh up to 1,650 pounds. Average sizes, though, are more in the range of 16 feet and 500 pounds. They live throughout sub-Saharan Africa, the Nile Basin, and Madagascar in rivers, freshwater marshes, and mangrove swamps.

The diet of the Nile crocodile is mainly fish, but it will attack almost anything unfortunate enough to cross its path, including zebras, small hippos, porcupines, birds, and other crocodiles. It will also scavenge carrion, and can eat up to half its body weight at a feeding.

One unusual characteristic of this fearsome predator is its caring nature as a parent. Where most reptiles lay their eggs and move on, mother and father Nile crocs ferociously guard their nests until the eggs hatch, and they will often roll the eggs gently in their mouths to help hatching babies emerge. Hunted close to extinction in the 1940s through the 1960s, local and international protections have helped them rebound in most areas. In some regions, though, pollution, hunting, and habitat loss have severely depleted their numbers.

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Kangaroos are large marsupials that are found only in Australia. They are identified by their muscular tails, strong back legs, large feet, short fur and long, pointed ears. Like all marsupials, a sub-type of mammal, females have pouches that contain mammary glands, where their young live until they are old enough to emerge.

Kangaroos are in the Macropodidae family, which also includes tree-kangaroos, wallabies, wallaroos, quokkas and pademelons. When people think of kangaroos, the four species that typically come to mind are in the genus Macropus: the antilopine kangaroo, the red kangaroo, the western gray kangaroo and the eastern gray kangaroo. They are sometimes referred to as the "great kangaroos" because these species are much larger than other kangaroos. 

Most kangaroos live on the continent of Australia, though each species has a different place it likes to call home. For example, the musky rat-kangaroo likes to nestle down in little nests on the floor of the rainforests in northeastern Queensland. Gray kangaroos like the forests of Australia and Tasmania, on the other hand. The antilopine kangaroo can be found in the monsoonal eucalyptus woodlands of extreme northern Australia. Tree-kangaroos live in the upper branches of trees in the rainforests of Queensland, as well as on the island of New Guinea. 

Kangaroos are herbivores. They eat grasses, flowers, leaves, ferns, moss and even insects. Like cows, kangaroos regurgitate their food and re-chew it before it is ready to be totally digested. 

According to the IUCN's Red List of Threatened Species, 16 species of tree-kangaroos and rat-kangaroos are listed as either near threatened, threatened, vulnerable, endangered or critically endangered. The desert rat-kangaroo and the Nullarbor dwarf bettong are considered extinct. Studies show that global warming could also kill off the world's smallest kangaroo. The four species of great kangaroos are not endangered.

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There are about a thousand mountain gorillas remaining on Earth, and about half live in the forests of the Virunga mountains in central Africa. Mountain gorillas are a subspecies of eastern gorilla (Gorilla beringei). As their name hints, they live in the mountains at elevations between 8,000 and 13,000 feet.

These gorillas live on the green, volcanic slopes of Rwanda, Uganda, and the Democratic Republic of Congo—areas that have seen much human violence from which the gorillas have not escaped unscathed. Habitat loss is a major threat: agriculture, illegal mining, and forest destruction for charcoal production have degraded their forests. They often get caught in snares laid out to trap other animals for bushmeat. Climate change also poses a threat: While gorillas are adaptive, moving to higher elevations to adapt to warmer temperatures, those areas are densely populated with little forest remaining. Catching illnesses from humans is also a threat. The majority of mountain gorillas are habituated to human presence because of the tourism industry, and while there are strict sanitation protocols in place and touching the gorillas is prohibited, disease could spread quickly.

Gorillas can climb trees, but are usually found on the ground in communities of up to 30 individuals. These troops are organized according to fascinating social structures. Troops are led by one dominant, older adult male, often called a silverback because of the swath of silver hair that adorns his otherwise dark fur. Troops also include several other young males, some females, and their offspring.

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The platypus is one of the most unusual creatures in the animal kingdom. Platypuses (which is the correct plural form, not "platypi") have a paddle-shaped tail like a beaver; a sleek, furry body like an otter; and a flat bill and webbed feet like a duck. In fact, the first time a platypus was brought from Australia to Britain, people couldn't believe that it was a real animal. 

A typical platypus is 15 inches (38 centimeters) from its head to the end of its rump. Its tail adds an additional 5 inches (13 cm) to the animal's length. An individual weighs about 3 lbs. (1.4 kg), though platypuses that live in colder climates are bigger than those living in warmer areas, according to the Australian Platypus Conservatory. 

Scientists have found fossils that suggest that ancient platypuses where twice as large as the modern variety, at 3.3 feet (1 meter) long.

Platypuses live in only one, small area of the world. These creatures make their homes in the freshwater areas that flow throughout the island of Tasmania and the eastern and southeastern coast of Australia. While they are in the water a lot, they will also waddle onto the riverbanks to dig burrows with their claws. These burrows are tunnels that have rooms or chambers. Platypuses also live under rock ledges, roots or debris.

Platypuses are carnivorous, which means they eat meat but not plants. They hunt for their food in the water where they live. As they swim, they try to detect food along the muddy bottom of the river, stream, pond or lake using their sensitive bills. When platypuses find something interesting, like shellfish, insects, larvae or worms, they scoop it up in their bills, store it in their cheek pouches and swim to the surface. Since they only have grinding plates and no teeth, platypuses use any gravel or dirt they scooped up while on the bottom of the waterbed to mash their food into digestible pieces. 

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Giant pandas are bears that are native to China, where they are considered a national treasure. Despite their exalted status, giant panda (Ailuropoda melanoleuca) populations are vulnerable: fewer than 1,900 live in the wild, according to the Smithsonian National Zoo. About 300 live in zoos around the world.

For the most part, giant pandas are loners. They dislike being around other pandas so much that they have a heightened sense of smell that lets them know when another panda is nearby so it can be avoided, according to the National Geographic. If they do come in contact with one another they'll growl, swat and bite each other until one gives up and leaves.

On average, a giant panda's territory is about 1.9 square miles (5 square kilometers). To mark their territory, giant pandas secrete a waxy scent marker from a scent gland underneath their tail. Other giant pandas can likely tell the sex, age, reproductive condition, social status and more by sniffing the potent marker, according to the San Diego Zoo.

The only time that giant pandas seek each other out is during their spring mating season. Males will use their sensitive smelling ability to sniff out a female when ready to mate. Females mate every two to three years.

Male pandas, like many other mammals (but not humans) have a baculum, a bony rod in the soft tissue of the penis. In most bears, it is straight and directed forward. However, in giant pandas, it is S-shaped and directed backward, according to the Animal Diversity Web.

The average gestation time is 135 days, but ranges between 100 and 180 days. Females give birth to one or two cubs (although the second cub usually doesn't survive) that only weigh 3 to 5 ounces (85 to 142 grams) and are about the size of a stick of butter, according to the San Diego Zoo. The cubs are completely blind for about 50 to 60 days and begin crawling at about 10 weeks of age.

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The Iberian lynx (Lynx pardinus) is a wild cat species endemic to the Iberian Peninsula in southwestern Europe. Lynx are long-legged, large-pawed cats with tufted ears, hairy soles, and a broad, short head. The coat, which forms a bushy ruff on the neck, is tawny to cream in colour and somewhat mottled with brown and black; the tail tip and ear tufts are black. In winter the fur is dense and soft, with hairs up to 10 cm (4 inches) long, and is sought by humans for trimming garments. Most lynx range in size from about 80 to 120 cm (about 32 to 47 inches) long, without the 10- to 20-cm (4- to 8-inch) tail, and stand about 60 cm (24 inches) tall at the shoulder. Weight typically ranges from 10 to 20 kg (22 to 44 pounds), though Eurasian lynx are often larger. In all species males are larger than females.

Nocturnal and silent except during the mating season, lynx live alone or in small groups. They climb and swim well and feed on birds and small mammals. The bobcat and the Eurasian lynx will take larger prey such as deer. The Canada lynx depends heavily on the snowshoe hare (Lepus americanus) for food, and its population increases and decreases regularly every 9 or 10 years, relative to the population of its prey.

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Adélie penguins are one of only 5 species of penguins that live on the Antarctic continent (Adélie, emperor, gentoo, chinstrap and macaroni penguins).

Adélie penguins breed around the entire Antarctic coast and small islands in places where there is exposed rock. More than 80,000 pairs of Adélie penguins breed annually along the 40km of Antarctic coast near Mawson station. Scientists at the Australian Antarctic Division study the Adélie penguin colony on Béchervaise Island, near Mawson as part of a long term ecosystem monitoring program. This colony is one of the smaller Adélie colonies consisting of around 1800 breeding pairs.

Adélie penguins are medium sized penguins, weighing 3 to 6 kg and standing 70 cm tall. They are distinguished by the white ring surrounding the eye. Males and females are of similar size and difficult to tell apart.

Like all penguins, Adélies are excellent swimmers. They are also very determined and successful long distance walkers travelling across many kilometres of fast ice on the return journey to their colonies. Their walking speed on ice averages 2.5 km/h and swimming speed 4 to 8 km/h. When enough snow covers the ice, they prefer to plonk onto their bellies and toboggan.

The diet of Adélies differs according to the location where food is captured. Local meals (those within 20km of the colony) consist mostly of fish, amphipods and ‘crystal krill’, while offshore meals consist of mainly ‘Antarctic krill’. Meal sizes range from about 300 to 650 g depending on the size of the chicks.

Breeding adults swim between 5 to 120 km offshore to catch food for their chicks. Feeding trips range from 5 to 72 hours in duration.

Some Adélie penguins are capable of diving to depths of up to 175 m but usually feed within the upper 70 m of the water column.

Credit : Australian Antarctic Program

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The toco toucan, the largest and best-known toucan species, is at home in South America's tropical forests. Its oversized, colorful bill has made it one of the world's most popular birds: They're familiar commercial mascots, known for hawking stout, cereal, and other products. They can weigh nearly two pounds and grow to 25 inches long, with their bill accounting for nearly half of their length.

Indigenous peoples regard the bird with a sacred eye; they are traditionally seen as conduits between the worlds of the living and the spirits.

Toco toucans feed either individually or in small flocks in the canopy. They tend to hop more than they fly. Their bright colors provide good camouflage in the dappled light of the rainforest canopy. The birds keep up a racket of vocalizations—mainly grunting and snoring sounds—that are often compared to the croaking of frogs.

These toucans nest in tree cavities and usually lay two to four eggs, which both parents take turns incubating. Young toucans do not have a large bill at birth—it grows as they develop and does not become full size for several months.

These iconic birds are listed as "least concern" by the International Union for the Conservation of Nature because they occupy such a large range. The species' overall numbers, however, are declining. They are hunted for food and for the pet trade, where their bright colors and intelligence make them popular.

Credit : National Geographic

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Leopard seals are solitary animals that inhabit pack-ice surrounding the Antarctic continent. They are perhaps the greatest wanderers of the Antarctic seals with sightings in Tasmania and a northern record at Heron Island. Heron Island is a subtropical island in the southern part of the Great Barrier Reef — quite some distance from the Antarctic!

They may occupy some sub-Antarctic islands year-round including Heard Island. In the winter months, young leopard seals from the south visit Macquarie Island.

The only natural predator of leopard seals is the killer whale. An observation of a male elephant seal having killed a leopard seal at Heard Island has been reported, however, this is likely to be an uncommon occurrence.

Our researchers are interested in the factors that drive the cyclic nature of the occurrence of leopard seals at Macquarie Island and Tasmania, and are studying seal movements within the pack-ice zone.

Leopard seals eat almost anything, including penguins, fish, squid, and crustaceans. Like the crabeater seals, leopard seals have unusual teeth for straining krill from the water. They also eat the pups of other seal species including crabeater, Weddell and southern fur seals. One leopard seal, captured near Sydney, had eaten a fully grown platypus.

Typically leopard seals chase or grab penguins in the water and thrash the captured bird back and forth until the skin peels away. The remaining carcass is then consumed.

Leopard seals have very individual tastes. Some remain near penguin colonies to capture prey, while others prefer to eat crabeater seal pups. Other leopard seals prefer a sub-Antarctic menu migrating north to Heard Island to feed on penguin and seal pups there.

Credit : Australian Antarctic Program

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