My Science School

Elephant skin can be upto 1.5 inches thick in certain places. Despite this, an elephant's skin is very sensitive, to the point where it can feel a fly land on its back. The skin is also sensitive to changes in its environment. Surprisingly it is also sensitive to the sun, and baby elephants are even known to get sunburn.

Elephant skin, unlike human skin, is resistant to shedding, so the layers – particularly the super-tough top layer, the stratum corneum -- stick around longer before sloughing off. It also has a lot more keratin (the stuff that makes up fingernails) than human skin, so it's more durable. As this thick hide is subject to everyday movement, like bending and twisting, it quickly wrinkles, with layer upon layer of wrinkly skin serving as a complex system of channels that capture and hold moisture and dirt.

So when you see elephants basking in sloppy pools, spraying water and mud to and fro, they aren't just doing it for the hilarity. The filthy goo settles into the teensy cracks in their skin, some of which are just a micrometer across, about 50 times smaller than the naked human eye can detect. Continually wetted, the skin remains permeable, helping the animals stay cooler.

Interestingly, elephant skin doesn't just randomly wrinkle — it cracks in geometric shapes that approximate other common sights in our world, from drying mud to heat-shattered asphalt, or even geometrically precise rock breakage like the Giant's Causeway in Ireland. The result is a durable cooling system that keeps these gigantic mammals from cooking in their own thick skin on steamy summer days.

Credit : How Stuff Works 

Picture Credit : Google

Seals can sleep with half of their brains up and working with the other half completely asleep. This is called 'unihemispheric slow-wave sleep'. It gives a whole new meaning to the term 'sleeping with one eye open' as on the side of the brain that is asleep, the eye will close, and on the side that is awake the eye will be open!

This sleep occurs while they are in the water, but when they come up to sleep on land, they sleep with their whole brains turned off like humans.

The study's first author, University of Toronto PhD student Jennifer Lapierre, made this discovery by measuring how different chemicals change in the sleeping and waking sides of the brain. She found that acetylcholine -- an important brain chemical -- was at low levels on the sleeping side of the brain but at high levels on the waking side. This finding suggests that acetylcholine may drive brain alertness on the side that is awake.

But, the study also showed that another important brain chemical -- serotonin -- was present at the equal levels on both sides of the brain whether the seals were awake or asleep. This was a surprising finding because scientist long thought that serotonin was a chemical that causes brain arousal.

These findings have possible human health implications because "about 40% of North Americans suffer from sleep problems and understanding which brain chemicals function to keep us awake or asleep is a major scientific advance. It could help solve the mystery of how and why we sleep" says the study's senior author Jerome Siegel of UCLA's Brain Research Institute.

Credit : Science Daily 

Picture Credit : Google

The mugger, also known as the marsh crocodile, is a crocodile of medium to large size with the broadest snout of all the living members of the genus Crocodylus. It lives in the Indian subcontinent as well as other countries in southern Asia. They are more alligator-like than any other crocodile, especially in their rounded snout, as most crocodiles have a snout that is pointier. Like most crocodilians, muggers feature a flat head where their eyes, ears, and nose are on top. This enables them to see, hear and breathe above water when their bodies are underwater. They have webbed feet but do not use them for swimming, using their strong, flat tail instead. “Mugger” is corruption from an Indian word that means “water monster.”

The mugger crocodile occurs in the Indian subcontinent as well as surrounding countries: Sri Lanka in the east, Iran in the west, and also Pakistan and Nepal. This species is found in freshwater lakes, marshes, and ponds, and has also adapted well to reservoirs, human-made ponds, irrigation canals, and coastal saltwater lagoons. This crocodile likes shallow water no more than 5 m deep, and it avoids fast-flowing rivers. It will sometimes bury itself into the mud to avoid the searing heat in India in the dry season.

Muggers are highly social and their social behavior includes gregarious behavior, communication, territorial activities, and dominance interactions. Between adults and also adults and their young there are many vocalizations. Most of the socializing take place during the seasonal mating activities. Body postures like snout raising and tail thrashing are used by males when establishing territories and trying to gain dominance before courtship and mating. Like other crocodile species, activities include basking, diving, and swimming. In addition, a unique and important activity is burrowing. Burrows are used for thermoregulation during hot and cold periods of the day and at night muggers come out to seek food. During dry seasons, muggers walk many kilometers overland in search of water and prey and they can chase prey for short distances on land. They are adapted better than most other crocodiles to life on land.

Muggers are primarily carnivorous, eating mostly fish, frogs, crustaceans, insects, mammals, birds, and sometimes monkeys and squirrels. They also scavenge on dead animals.

Credit : Animalia 

Picture Credit : Google

Gharials are one of the largest members of the crocodilian family. They look very similar to crocodiles and alligators, but they have a distinctive long, narrow snout, which reduces water resistance and helps them to hunt for fish. Historically, they lived in only four river systems in the world, but have now become extinct in many areas. The gharial is now listed as a Critically Endangered species. Read on to learn about the gharial.

Gharials have a typical crocodilian shape, other than their extremely elongated, narrow snouts. They are covered with smooth, non-overlapping scales. Adults are generally a dark or light-olive color, and youngsters usually have speckling and dark cross-bands on their heads, bodies, and tails. They have partly webbed fingers and toes. Like other crocodilians, they have a very thick, powerful tail, which is flattened on the sides (“laterally compressed”).

The male gharial has a large, hollow swelling at the end of his snout that is known as a “nasal boss.” This only develops when he becomes sexually mature. This swelling, and the males’ greater body-size, makes it easy to distinguish between male and female gharials (i.e. sexual dimorphism), something which is rare among other crocodilians. The function of the nasal boss is not well understood, but it might be a visual sex indicator, or it might be used as a sound resonator.

Gharials generally prefer clear, flowing, freshwater rivers with deep pools and plenty of fish. They also like habitats with sand-banks or san-bars for nesting and basking in the sun.

Gharials are found in small populations in only a few localities in the Northern part of the Indian Subcontinent.

Young gharials eat small fish, frogs, tadpoles, and insects. Adults also feed on larger fish and crustaceans. Gharials do not chew their prey, rather, they swallow it whole.

Credit : Animals.net

Picture Credit : Google

Earth’s largest living crocodilian—and, some say, the animal most likely to eat a human—is the saltwater or estuarine crocodile. Average-size males reach 17 feet and 1,000 pounds, but specimens 23 feet long and weighing 2,200 pounds are not uncommon.

Saltwater crocs, or "salties," as Australians affectionately refer to them, have an enormous range, populating the brackish and freshwater regions of eastern India, Southeast Asia, and northern Australia. They are excellent swimmers and have often been spotted far out at sea.

Classic opportunistic predators, they lurk patiently beneath the surface near the water's edge, waiting for potential prey to stop for a sip of water. They’ll feed on anything they can get their jaws on, including water buffalo, monkeys, wild boar, and even sharks. Without warning, they explode from the water with a thrash of their powerful tails, grasp their victim, and drag it back in, holding it under until the animal drowns.

Salties are considered at low risk for extinction. But saltwater croc hides are valued above all other crocodilians, and illegal hunting, habitat loss, and antipathy toward the species because of its reputation as a man-eater continue to put pressure on the population.

Credit : National Geographic

Picture Credit : Google

The Nile crocodile has a somewhat deserved reputation as a vicious man-eater. The proximity of much of its habitat to people means run-ins are frequent. And its virtually indiscriminate diet means a villager washing clothes by a riverbank might look just as tasty as a migrating wildebeest. Firm numbers are sketchy, but estimates are that up to 200 people may die each year in the jaws of a Nile croc.

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.

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.

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.

Credit : National Geographic

Picture Credit : Google

The dwarf crocodile is the smallest species of crocodile in the world, growing up to 1.5 metres (4.9 feet) in length. When compared to the largest species, the saltwater crocodile (up to 5.2m/17 feet in length), they really do dwarf in comparison!

Dwarf crocodiles can be found in the mangrove swamps, rainforests and slow moving rivers and streams of West Africa and are mostly active at night when they like to feed on small animals such as fish, insects, lizards, water birds and shrews.

Dwarf crocodiles can lay up to ten eggs at any one time. Good diggers, the females lay their eggs in mounds of soil and vegetation. The female will dutifully guard the eggs until they hatch and will continue to look after the hatchlings once in the water.

The Dwarf crocodile is an African reptile. The area of its distribution stretches from sub-Saharan regions to west-central Africa, from southern Senegal to the Democratic Republic of the Congo, reaching as south as northern Angola. The primary habitat of the Dwarf crocodile is rainforest. The reptile occurs in tropical lowland regions, where the animal inhabits swamps with dense vegetation, slow flowing currents and rivers. In addition, the Dwarf crocodiles are sometimes found in savannah pools.

Credit : Folly Farm 

Picture Credit : Google

Baya weaver is a weaverbird found across the Indian Subcontinent and Southeast Asia.

During non-breeding season, plumage of both males and females resemble female house sparrow. During breeding season, the male's plumage turns into yellow. It will have a bright yellow crown, dark brown mask, blackish brown bill, yellow breast and cream buff below.

 It is a social and gregarious bird. It is known for its uniquely-shaped nests. The male starts building a pendulous nests using long strips of paddy leaves, and rough grasses during the breeding season. The females inspect and choose a nest before signalling their approval to pair with the male.

During the breeding season the males begin building nests. The nests are partially built when the males display to passing females by flapping their wings and calling while hanging to their nests. The call of the Baya males which is normally a sparrow-like chit-chit is followed by a long-drawn chee-ee in the breeding season. The females inspect and choose a nest before signalling their approval to a male. Once a male and a female are paired, the male goes on to complete the nest including the entrance tunnel, males are solely incharge of building the nests, though their female partners may join in giving the finishing touches. Studies have shown that nest location is more important than nest structure for the female decision making.

The males are polygynous, mating with 2 to 3 females one after another. Males build many partial nests and start attracting females. A male finishes the nest to its completion only after finding a mate, after mating the female lays about 2 to 4 white eggs and incubates them. The females are solely responsible for incubating and bringing up the brood. After mating with a female the male goes on to woo more females with its other nests.

Credit : Beauty of Birds

Picture Credit : Google

Snow leopard is found only in mountain regions of Central and South Asia. Its fur is whitish to grey with black spots on head and neck, with larger rosettes on the back. It has bushy tail and pale green eyes. It is active at dusk and dawn and it hunts wild goats, sheep, hares, rodents and birds. It uses its unique coat to camouflage itself in the snowy landscape.

Few humans have seen snow leopards in real life, but hunting scenes like the one above have been captured on video by researchers who spend countless hours searching the mountains of Central Asia for snow leopards. Researchers think only 3,500 to 7,000 snow leopards exist in the wild, but no one knows for sure.

Snow leopard experts need to gather more information about the secretive cats’ lives to help protect them. To do that, researchers use high-tech tools to spy on the shy animals. They gently trap the wild cats to examine them and put on satellite radio collars to track where the cats roam. Motion-activated digital cameras capture images of snow leopards, exposing many new details about how many there are, how they live, and what threatens their survival.

Even though snow leopards live in some of the most rugged mountain terrain on Earth, people pose the biggest threat to their survival. Poachers can sell a snow leopard’s hide and bones for thousands of dollars. Herders often kill any snow leopard that attacks their livestock. Hunters target ibex, wild sheep, and other animals for food and trophies—removing important snow leopard prey. The more scientists can learn about snow leopards, the better they can protect these rarely seen cats from humans who harm them.

Credit : National Geographic

Picture Credit : Google

The sunflower sea star, found in the northeast Pacific is among the largest sea stars found in the world. It has a maximum arm span of 1 metre.

It has the longest arm spread of any sea star, measuring about 40 inches from tip to tip, and it is also the heaviest, weighing up to 11 pounds. It also has the most arms of any animal known to science.

Aside from its size, the number of arms is what makes this sea star so incredible. Adults have up to 24 symmetrically placed arms, which is more than any other known species.

Because some individuals are a deep yellow, they resemble sunflowers, with all of the arms resembling petals. The hue yellow isn’t the only one available; sunflower stars also come in purple, orange, red, and brown variations.

They are paler beneath, with thousands of yellow or orange tubular feet. These feet act like suction cups, providing the sea stars with a firm hold and assisting them in catching and opening their mollusk, sea urchin, and crab prey.

The feet are also utilized for walking, and according to the Monterey Bay Aquarium, this species can travel at a remarkable rate of up to 40 inches per minute.

Credit : American Oceans 

Picture Credit : Google

Macaroni penguins have distinctive yellow feather crests on their foreheads. The yellow-crested penguins, which moult once a year, were named after the hats with feathers worn by dandy men in the 18th Century which were called macaronis.

Their habitat is usually mountains and snow-covered rocky areas with little vegetation or soil. When inhabiting warmer areas, dirt, mud or vegetation may cover the surface of the land where they live. Therefore, they can walk and jump over large slippery rocks that rise in the costs without a problem.

Their largest colonies locate on islands such as South Georgia, Kerguelen, Heard, McDonald, Crozet and Marion Islands.

It is a migratory, aggressive and territorial penguin; males often become involved in fights with other individuals in the colony.

In some colonies, they stay near the coast, diving to a depth of 66 feet and stay submerged for two or three minutes to get food. They are proficient swimmers using their long tail as a rudder, and they have excellent underwater vision.

Besides the vocalizations, Macaroni species communicate with body movements used according to the situation. Grooming and care for their plumage, like all penguins, is essential at the moment of interaction to engage in social relations.

Credit : Penguins World 

Picture Credit : Google

Many species of birds in India are dying out, says the first major report in our country on the state of bird populations. Things are particularly bad for the birds of prey, due to reasons like habitat destruction, hunting and pet trade. Several raptors like various species of eagles and harriers have come down in numbers, but vultures are the worst hit. Seven out of the nine vulture species found in India, have been decreasing in number since the early 1990s, mostly poisoned by an anti-inflammatory drug given to livestock.

India is certainly taking steps to conserve these birds, and our government has signed a memorandum of understanding (MoU) to save several species of migratory birds of prey in Africa and Eurasia. This is usually called the Raptor MoU.76 species are covered by this, of which 50 are in India including the endangered vulture. The government has also launched the Vulture Action Plan 2020-25, for saving the vultures. We are also a member of the SAVE (Saving Asia’s Vultures from Extinction) consortium.

Picture Credit : Google

The tawny owl, or Strix aluco, is a medium-sized owl which belongs to the family Strigidae. This owl is found in woodlands across Eurasia and North Africa. It is sometimes called the brown owl because of its colouring, which is brown and sometimes gray. Its underparts are pale with dark streaks and it has a large, roundish head with dark eyes. Ear tufts are absent but it has exceptional hearing due to a symmetric ears. In fact, this owl’s hearing is 10 times better than a human’s! Often it uses only its ears while hunting at night.

This owl is non-migratory and fiercely territorial. So much so, that if a young owl fails to find a vacant territory within its home range, it will rather starve to death than move away! The tawny owl has the most iconic owl call or whistle. Its plaintive ‘Tu-whit tu-whoo’ has been immortalized in literature and films, as the quintessential owl cry.

It eats worms, insects, small mammals, reptiles, amphibians, fish and smaller birds. It usually creeps up on its prey with silent wings while the hapless victim is perched in a tree sleeping, or moving on the ground.

The tawny owl nests in tree holes, old magpie nests and cavities in buildings. The female typically lays around 2 to 3 glossy, white eggs which she incubates over a period of 30 days. Both parents look after the chicks for 2 to 3 months even after they have learnt how to fly. This species is very aggressive when defending their young. It will attack any intruder by striking them with its sharp talons. Because its flight is silent, it may not be detected until it is too late to avoid the danger. Dogs, cats and humans have been assaulted by them, sometimes without provocation.

The tawny owl is categorized under ‘Least Concern’ in the IUCN Red List, due to its stable population and wide range.

Picture Credit : Google

The spotted owlet, or Athene brama, is an elegant little raptor that belongs to the family Strigidae. It is grayish-brown in colour with white spots all over its body. It has a roundish head, a pale facial disc, yellow eyes and prominent white eyebrows. Its upperparts are gray-brown - heavily spotted with white and its underparts are white - streaked with brown.

It is found in tropical Asia from mainland India to South-east Asia, where it prefers open to semi-open areas near farmland or human habitation. It is well adapted to living in and near cities due to the availability of rodents and insects like rats and cockroaches in these areas. It is known to use street lamps as hunting bases, since the light attracts insects which it can easily catch.

It is generally active at dusk and before dawn, but is sometimes seen during the day. At other times, it may be seen roosting in small groups or as a pair in tree holes or on branches. It also hunts bats, squirrels, toads, small snakes and scorpions. Its call is a loud

‘chirurr-chirurr-chirurr’ which ends in a ‘chirwak-chirwak’.

These owls are cavity nesters and females will lay 3 to 5 eggs at a time. Incubation lasts for 26 to 31 days and both parents share incubation duties. It is listed under ‘Least Concern’ in the IUCN Red List, since its population has remained stable over the years.

Picture Credit : Google

The jungle owlet, or Glaucidium radiatum, is a small, rotund bird that belongs to the family Strigidae. It is found in India, Nepal, Bangladesh and Bhutan - where it inhabits scrub and deciduous forests in the Himalayas from Dalhousie in the west, to Bhutan in the east. It is also found south through peninsular India to north and east Sri Lanka.

This owlet is dark brown on its upper parts and finely barred all over in brown and white. For this reason it is also called the barred jungle owlet. It has a rounded head, brownish wings and a narrowly barred tail. It has a whitish patch on the chin, upper chest and in the centre of the abdomen. It has yellow eyes, a greenish beak and black claws. Its facial disc is indistinct and the false eyes that many owlets have at the back of their heads (to Scare off predators), is missing in this species.

This owl is most active at twilight and an hour or so before dawn. Such birds are called ‘crepuscular’. Although they will fly and hunt during the day (especially if the weather is cloudy), they are most likely to be seen roosting on a tree branch in the daytime. Their call is a loud musical trill, ‘praorr-praorr-praorr-praorr’.

This little raptor is an insect connoisseur! Its diet mainly consists of beetles, grasshoppers, locusts and cicadas. It also eats molluscs, lizards, mice and small birds. It is very tenacious and fearless when it comes to hunting and has strong talons to help it catch its prey.

This owlet makes its nests in natural tree hollows or abandoned woodpecker holes. Not much information exists about the incubation or breeding habits of this species. The female lays 3 to 4 roundish, white eggs. Most nest sites are 3 to 8 meters above the ground. This species is listed under ‘Least Concern’ in the IUCN Red List due to its large range.

Picture Credit : Google