Category Nature Science & Wildlife

Where can we find the perentie, the fastest reptile?

Generally considered the fastest recorded reptile, the perentie, is most commonly found in Australia. It is Australia’s largest lizard, and grows to over 2.5 metres in length. It has a long neck with a stout and robust body, and has a long, tapering tail as well. Perenties have a yellow body, or a cream body with tawny brown rosettes edged in dark brown on their back. They have dark limbs with white spots, with a head and neck that are pale creamy- white with a reticulated pattern of black lines and flecks.

Perenties are found in the arid parts of South Australia, Western Australia, Queensland, and the Northern Territory, where they are usually found around rocky hills and outcrops. They often find their shelter in burrows that they dig themselves. These burrows can be extensive and have several escape exits.

The diet of younger perenties include lizards, insects, and small mammals. As they grow, they will spontaneously attack large venomous snakes, rabbits, birds and their eggs, and even small marsupials such as wallabies. They are rarely seen as they are extremely shy and live in remote areas away from human habitation. They are considered to be a species of least-concern according to the International Union for Conservation of Nature (IUCN).

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Nature’s masterstroke

Autumn showcases nature in all its splendour. How do the colours of leaves change during the season? Why do leaves fall? How do animals react to the change in season? Come, let’s find out

Autumn is a transitional period between summer and winter. It is one of the four seasons in the temperate zones. According to the Hindu calendar. Sharad ritu is synonymous with autumn. But autumn

is not very distinct in India, except in some parts of the Himalayas, especially the Kashmir Valley. In the northern hemisphere, autumn begins with the September equinox which occurs on September 22 or 23 each year. This is when the sun crosses the celestial equator and moves southward. During the equinox, the day and night are of nearly equal duration.

Fall colours

French littérateur Albert Camus has aptly described the season- “Autumn is a second spring when every leaf is a flower!” Indeed as the days grow shorter with a perceptible nip in the air, Mother Nature too begins to discard her universal green and sets the countryside on fire with gorgeous red, orange, yellow or brown.

The leaves of many deciduous plants change colour. A leaf contains three pigments-chlorophyll (green), carotenoid (yellow, orange and brown) and anthocyanins (red). Of these, chlorophyll and carotenoid are present in leaf cells during the growth period. But the chlorophyll covers the carotenoid and hence we see only the green colour. Anthocyanins are produced only in autumn under certain conditions in some trees.

During winter, there is not much sunlight for photosynthesis to take place. Trees begin to temporarily shut down their food factory. The green chlorophyll begins to disappear from the leaves and the vivid colours of the carotenoid come alive.

The eastern parts of the U.S. and Canada, Scandinavia, western parts of Europe, China, Korea and Japan are famous for the spectacular fall foliage. Thousands of tourists flock to these places to soak in the flamboyance of nature before everything gets covered by a white blanket of snow!

Why do leaves fall?

The root, stem and branches of trees are able to withstand the harsh winter but not so the tender leaves- they freeze in winter. Therefore, the leaves are shed to ensure the tree’s survival. With the onset of autumn, a layer of cells called the ‘separation layer forms at the base of each leaf. When this layer is complete, the leaf is separated and it falls.

Trivia

*As the mercury begins to drop in the late fall season, people look forward to the ‘Indian Summer’. It is an unusually warm, dry spell which follows frosty weather.

*Autumn is associated with a sense of melancholy, especially by poets. “To Autumn” by well-known English poet John Keats is an ode to the season.

*Chinar, the signature tree of Kashmir, paints the entire valley in gold and crimson red during autumn.

* In the West, the new academic year in schools and colleges coincides with the fall season.

ANIMAL KINGDOM

Come autumn and animals know instinctively that the fun and frolic of summer is over and it’s time for hard work! The falling temperature and reducing daylight trigger hormonal changes in animals. Many birds, animals and even insects begin their long, arduous journey to warmer places to escape the harsh weather ahead

Those who wish to stay put find their own ways to brave the winter. Furry animals grow a thicker coat, while birds grow extra feathers. As autumn gets underway, squirrels, beavers, rodents and even ants get busy gathering food for a snowy day. For those who plan to sleep through winter, autumn is feasting time! Bears chipmunks, hedgehogs, etc. consume excess food and store it as body fat to sustain them during hibernation.

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ACCORDING TO INTERNATIONAL UNION FOR CONSERVATION OF NATURE ,WHICH WILDLIFE SPECIES IS FACING EXTINCTION IN INDIA?

The International Union for Conservation of Nature says these wildlife species found in India are facing an extremely high risk of extinction in the wild.

FEW LEFT: The Gundia frog (Indirana gundia) is a resident of a patch of forest in the Western Ghats. As forests are cut down to make way for construction, this frog is slowly losing its home.

DOWNWARD SPIRAL: The population of red-headed vultures has decreased by over 90% in just 10 years. Most of the birds died after feeding on the carcasses of livestock treated with diclofenac, a non-steroid painkiller used by farmers and veterinarians.

POSITIVE NOTE: The gharial (Gavialis gangeticus) was once found across Bangladesh, Bhutan, India, Myanmar, Nepal and Pakistan. It currently survives in several severely fragmented populations in India and Nepal. Conservation programmes in India are slowly improving numbers.

DEEP TROUBLE: The Indian swellshark (Cephaloscyllium silasi) is found in the western Indian Ocean. Their numbers are falling due to overfishing.

LOST RODENT: Sightings of the Large Rock Rat, also known as the Elvira Rat, are so rare that there are few photographs of them. This is an illustration of the species (Cremnomys elvira) by the Zoological Survey of India.

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DO CROCODILES LAY EGGS?

Yes, and they look after them very carefully. Female crocodiles scoop out a pit in the ground then lay 30 or more eggs there, covering them up with earth or sand. The female will stay nearby, guarding the nest for about three months while the eggs become ready to hatch.

Crocodiles stayed within the egg-laying branch of the family along with alligators, caiman, and gharials who all lay hard-shelled eggs. Sexually mature females over the age of 10 years who have reached a certain trigger weight will lay a clutch of eggs into the soft, cool earth and build up a shallow mound on top of it.

Their eggs are very dependent on the temperature of the ground and so different crocodiles lay their eggs at different times and different places depending on this as a key factor. Unlike birds, crocodile eggs are born unsexed – the sex of the young isn’t predetermined by their chromosomes. It is the temperature that determines whether they grow up male or female. Mother crocs will sometimes build up or shallow out a nest if the temperature varies too much from ideal. It is a delicate business in the wild – but a very useful tool for captive-bred individuals.

How Many Eggs Does A Crocodile Lay?

The crocodiles go for the ‘more is best’ approach to young – laying up to 60+ eggs in one clutch. Some larger/older crocodiles can lay many more and younger/smaller females often many less. Regardless of the number, the nest-building process remains the same – with the same digging technique and locations. All the eggs are hard-shelled although they are translucent when first laid, only becoming solid white just before hatching.

Crocodile eggs are about the same size as a large chicken egg but are a different shape. Reptile eggs don’t have one end larger than the other and are certainly not pointed at the end. They are more capsule-like and symmetrical at each end. They are also considerably heavier at around 85g (3oz) – where a large chicken egg only weighs around 57g (2oz).

Where Do Crocodiles Lay Their Eggs?

If you were thinking of going out and finding yourself a haul of crocodile eggs for a feast – the American Alligator is listed as ‘threatened’ by the IUCN – so poaching their eggs without the right permit will be illegal, unethical, and also highly dangerous.

They tend to lay their eggs in March or April and the soft sedimentary or clay soils are easy for mum to dig. A large flat area of earth found in an otherwise leaf and twig-covered woodland area is almost certainly a crocodile nest – but take care – mum is always close by. Predation of crocodile eggs is quite common – with the raccoon being the most likely thief. Other predators might be bears, birds and even other reptiles – so mum is usually watching out for any disturbance.

She has to listen out for the young to start chirping just before they hatch – so if she can hear a newborn crocodile that is buried underground – she will certainly hear you!

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HOW DO CROCODILES HUNT?

They usually lie and wait in shallow water until animals come to drink. Then they make a sudden lunge, grab the victim with their massive, snapping jaws, drag it into the water and drown it.  Many species are able to kill and eat large mammals such as zebras, wildebeests and humans. Once it has caught its prey, a crocodile will then drag it into the water and drown it. It eats its prey by biting off large chunks of meat and swallows them whole. Other species, such as the Chinese alligator and gharial, feed primarily on fish or invertebrates.

Observing crocodile hunting behaviour is very tricky. These animals hunt by ambush, they eat infrequently because their metabolism is slow, and nearly all hunting occurs at night and/or in muddy waters. Vladimir Dinets, a researcher working at the University of Tennessee, took a new approach. Beyond more than 3000 hours of his own observations, he utilised Facebook and other social media to collect the findings of nature lovers and crocodile researchers, and also reports of spontaneous encounters with crocodiles. Dinets also searched the old notebooks of other scientists. Although this search yielded just a few handfuls of observations, some of which went back as far as the 19th century, all of the observations described the coordination and collaboration between crocodiles for hunting purposes. As numerous people on different continents all described this behaviour in the same way, Dinets found the information dependable. For instance, the crocodiles swam together to drive a school of fish into a tight group, and then took turns grabbing fish from this ‘bait ball’. Another observation involved a large saltwater crocodile that scared a pig, causing it to run into a lagoon where two smaller crocs were hiding and waiting. It is assumed that the large crocodile knew about the two others, even though they were not visible.

All in all, Dinets concludes that crocodiles are – perhaps right behind humans – some of the most expert hunters. At the same time, the scientist admits that we still have much to learn about their behaviour.

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WHAT IS A TAIPAN?

The taipan is a poisonous snake from Australia. It can grow up to three metres long, which is huge for a venomous snake. It belongs to the same family as the cobra, and has venom in its front fangs.

Where do Taipans Live?

Two of the three taipan species are endemic to Australia, specifically in northern and eastern coastal and central Australia. The coastal taipan, however, also occurs in southern Papua New Guinea. They primarily live in deserts, floodplains, grasslands, oil palm plantations, cane fields, dry forests, and savanna woodlands.

There are three species of taipans: (1) the inland taipan (Oxyuranus microlepidotus); (2) the coastal taipan (Oxyuranus scutellatus) or Papua New Guinean taipan; and (3) the western desert taipan (Oxyuranus temporalis). Table 1 below shows the general characteristics and behavior of each taipan species.

What do Taipans Eat?

Taipan snakes’ diet is primarily composed of mammals such as mice, rats, and bandicoots, with minor variations between inland and coastal taipans. Their hunting strategy also varies. The western desert taipan, however, is not yet fully understood and experts have limited data on its hunting behavior.

Inland taipans feed exclusively on mammals such as long-haired rats and house mice. Those in captivity have been observed to eat one-day-old chicks. When hunting, inland taipans corner their prey in narrow crevices such as soil cracks, then bite them several times in quick succession. Their venom’s high potency allows them to hold their prey while waiting for it to die. This strategy is challenging for some snakes because the prey may retaliate while the venom takes its effect.

Coastal taipans feed on small mammals such as rodents, bandicoots, and quolls. There are also instances where they take birds as food. They begin their hunt by scanning their surroundings for prey using their well-developed sight. Once they have seen their target, they “freeze” for a while, launch forward, then administer their bites once or several times. After the attack, they release their prey and allow it to move away while the venom takes its effect, avoiding any lethal retaliation. The coastal taipan then tracks its dying prey using its tongue.

How Dangerous are Taipans?

The venom of taipans, specifically that of the inland taipan, is the most potent among the snake venoms based on laboratory studies on mice. The inland taipan can produce enough venom to kill 250,000 mice in one bite. However, there has been no record of human fatality related to inland taipan, which can be attributed to its shy and placid nature. In contrast, the coastal taipan has been associated with fatal bites in Australia and Torres Strait in New Guinea.

Picture Credit : Google