My Science School

It’s easy to think caterpillars and worms are the same. After all, they’re both usually slow-moving, and long and squiggly with the caterpillars even have the word worm in their name, adding to the confusion. But while they have a few similarities, caterpillars and worms are basically different creatures.

Similarities

Both caterpillars and worms can be pests or friends of humans and the environment. For instance, both can destroy plants (earthworms can eat the roots of a healthy plant, and caterpillars can polish off large quantities of leaves) but they are also food for larger creatures. While worms help with composting, butterflies and moths emerging from caterpillars help in the pollination of plants, many of which produce food for several creatures and humans.

The difference

Caterpillars are the larvae of butterflies or moths. Essentially, they are just a stage in the life cycle of an insect. Worms, on the other hand, are not a phase; they are tubular invertebrates. One of the most notable differences between the two is that worms do not have legs; caterpillars usually have three pairs of legs. Worms also normally do not have eyes. Instead, they have what are called receptors that help them sense if there’s light or darkness. Also, while worms seem to prefer areas that are dark and moist, caterpillars do not appear to be picky in that department.

Here’s a trivia coming your way. The fall armyworm, which has been getting a lot of attention for its large-scale destruction of crops in India, is not a worm at all. It is actually the larva of the fall armyworm moth!

 

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Rhinoceroses are large herbivorous mammals identified by their characteristic horned snouts. They are often classified as megafauna, which refers to animals weighing over 1,000 kg. Cave paintings suggest rhinos once roamed throughout Europe, Asia and Africa. But they are now restricted to Africa’s savannah and Asia’s tropical forests. As the world observes September 22 as Rhino Day, let’s take a look at how poaching is pushing the species to the brink.

Five extant species

There are five extant species of rhinoceroses – black rhinoceros and white rhinoceros of Africa; and Sumatran, Javan and Indian (greater one-horned rhinos) rhinos of Asia. White rhino has two subspecies – northern and southern. All the five species of rhinos have either one or two horns.

They live up to 45 years in the wild. While calves are attacked and consumed by big cats and hyenas, adults have no predators. However, they face threat from human poaches. The northern white rhino is on the brink of extinction with only two females of the species existing today. Three species of rhino – black, Javan, and Sumatran – are critically endangered. The conservation status of the greater one-horned rhino is vulnerable, while that of the southern white rhino is near threatened.

Why are they poached?

The rhinos are killed for their horns, which is prized in Asian countries Rhino horns are made of keratin – the same stuff that makes up your finger and toe nails. The horn is used in traditional Chinese medicine as a supposed cure for a range of illnesses. It is also used as a status symbol to display success and wealth.

There has been a huge surge in the poaching of rhinos since 2008 across the globe, particularly in South Africa, which has seen record numbers in recent years. On average, a rhino is killed every 15 hours there. Although international trade in rhino horn has been banned under the Convention on International Trade in Endangered Species of Fauna and Flora since 1977, high demand in Asian markets, especially Vietnam and China, drives the illegal trade.

Indian rhinos

By the beginning of the 20th Century, hunting and habitat loss had reduced the population of the greater one-horned rhino to fewer than 200 individuals. However, conservation efforts and anti-poaching measures in the last few decades have made a huge difference and the rhino population has rebounded to more than 3,600 today. Nevertheless, threat from poaching still remains.

Globally, rhinos also face threats from habitat loss, population fragmentation, inbreeding and disease outbreak.

 

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Laughter is the instinctive expression of amusement. We laugh by making sounds and movements of the face. Laughter is rhythmic, often audible contractions of the diaphragm and other parts of the respiratory system. To answer the question “Do animals laugh?”, animals such as chimpanzees, gorillas, bonobos, orangutans, rats, dogs and dolphins display behavior that is similar to laughter.

In 2009 Marina Davila Ross, a psychologist at the U.K.’s University of Portsmouth, conducted experiments in which she tickled infant and juvenile primates such as orangutans, gorillas, and chimpanzees. The apes responded by painting distinctively, which scientists say could be similar to laughing in humans. Their laughter is not readily recognizable to humans as such, because it is generated by alternating inhalations and exhalations that sound more like panting.

Apes may also have a good sense of humour. Koko, a gorilla at The Gorilla Foundation, in Woodside, California, who was trained in sign language, once tied her trainer’s shoelaces together and signed to her to chase.

Dogs sometimes pant in a manner that sounds like a human laugh, while rats emit long ultrasonic calls while playing and when tickled.

In 2004, researchers studying dolphins noticed a particular set of sounds – a short burst of pulses, followed by a whistle, made by them during play-fighting.

 

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Wood frogs inhabit parts of the U.S., Canada and the Arctic Circle which means, they must be prepared to deal with sub-zero temperatures. While different animals do different things – such as burrowing underground and migrating to warmer places – to escape the cold, creatures such as wood frogs embrace it – they simple freeze! Let’s see how they do it.

They become frogcicles!

When winter arrives and the first ice crystals fall on this freeze-tolerant frog’s skin, the frog begins to freeze. As this happens, the liver starts to produce large quantities of glucose. Once this glucose is released from the liver, it mixes with the bloodstream and is carried throughout the body through the pumping of the heart. Research says urea – produced by the frog’s urine – also blends with the glucose. This mixture helps prevent the cells from freezing completely, because that would mean the death of the frog. Only about 70% of its body fluid freezes. Meanwhile, the frog stops breathing, its heart too stops beating, and organs become inactive. The frog hardens – this is offhandedly referred to as a frogcicle, drawing from the word icicle. The creature is motionless and appears dead. This continues through the winter. While the role of glucose in keeping it alive when it is frozen has been understood, it is still not clear what causes the stopping of a beating heart. As for the frog, when Spring arrives, it begins to thaw, regains consciousness and recovers from its state within a day. And, life goes on – with a freeze-thaw cycle in place.

 

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Odd-looking, but cuddly

The pudgy and furry wombat is one of the oddest-looking animals on Earth – rather like a pig, bear and koala all rolled into one.

There are three species of wombat: the common wombat (Vombatus ursinus), the northern hairy-nosed wombat (Laisorhinus krefftii), and the Southern hairy nosed wombat (Lasiorhinus latifrons). You will be able to see all three in Australia and Tasmania, usually in forested and mountainous area.

Marsupial

Wombats are marsupials, related to koalas and kangaroos. They usually live up to 15 years in the wild, but can live past 20 and even 30 years in captivity. Rotund, with stubby tails, short ears and tiny eyes, wombats grow to around one metre in length and weigh anything between 20 and 40 kg. their fur is either sandy brown or grayish-black and this helps them blend with the landscape – a way of safeguarding themselves from predators.

Big eaters

These animals are nocturnal and emerge from their burrows to feed at night. Being herbivores, they feed on grasses, herbs, bark, and roots. They spend a lot of time, eating. They have sharp large incisors like rodents which help them gnaw at thick vegetation. Their teeth never stop growing. But they are slow to digest their meal – it takes around 8-14 days for them to fully digest their food. But this helps them adapt to Australia’s arid conditions. Since they derive most of the moisture they require from plants, they don’t need to drink much water either. And interestingly, they are the only creatures in the world to excrete poop that is cube-shaped!

Burrowing away!

They are amazing burrowers and dig lengthy burrow systems with their razor-sharp teeth and claws. Common wombats are shy and solitary and inhabit their own burrows, while the other two species may be more social and live together in large groups in their warren.

Quick sprinters

Wombats may look plump and slow, in fact, their walk is more of a waddle. Despite their podgy bodies and stubby feet, they can run really fast – even up to 40 km/h.

Just communicate

They communicate with one another in various ways – vocalizations, aggressive displays, and markings on logs and branches made by rubbing against them repeatedly. Wombats tend to be more vocal during mating season. When angered, they can make hissing sounds.

Jellybean or joey?

Female wombats give birth to a single young one known as a joey in the spring, after a gestation period of 20-21 days. When the joey is born, it is the size of a jellybean and not completely developed. The joey climbs into it mother’s pouch right after birth to finish developing and stays there for about five to six months. Wombats are weaned after 15 months.

Once pests, now protected

In 1906, the Australian government declared wombats pests and encouraged people to kill them. From 1925 to 1965, some 63,000 wombats skins were redeemed for cash. Fortunately, this practice has stopped. All species of wombats are protected in every state except for Victoria.

Powerful posterior

Startled wombats can charge humans and bowl them over, with the risk of broken bones from the fall, besides wounds from bites and claws. When running away from predators like Tasmanian devils and dingos, wombats rely on their thick rump skin to protect them. Their rear-ends are mostly made up of cartilage, which makes them more resistant to bites and scratches. At the end of a chase, wombats will dive into their burrows and block the entrance with their posterior. They’re also capable of using their powerful backs to crush intruders against the roofs of their burrows.

Wombat facts

• A group of wombats is known as wisdom, a mob, or a colony.


• Believe it or not, wombats can jump! Some have been known to jump over metre-high fences.


• The giant wombat, an ancestor of modern-day wombats, lived during the Ice Age and was the size of a rhinoceros.


• Since 2005, Wombat Day is observed in Australia on October 22.


• Wombats have featured in Australian postage stamps and coins and ‘Fatso’, the wombat, was the unofficial mascot of the Sydney 2000 Summer Games.

 

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Strange are the ways of the animal world. We think animals are “dumb”, but they have surprising ways of talking to each other. How do animals say “Hey, want to play chase-the-tail?” or “You think we can eat this?” Animal languages don’t have names and we can’t tell what they are saying, but we do know that dolphins whistle, hyenas laugh, wolves howl, lions roar, elephants trumpet, birds whistle, tweet and chirp, frogs croak – to send messages across. And making sounds isn’t the only way they can say “I love you!” They use a dictionary of non-verbal means!

Touch

Chimpanzees greet each other by holding hands, monkeys groom each other by picking off dead skin. Pets and domestic animals lick to show affection. But elephants would be the best examples for communicating through touch. They deliberately touch one another with their trunk, tusks, feet, tail and sometimes through their entire body – to explore, play, protect, fight. Have you seen elephants greeting others with a raised trunk? Use their ears to rub a mate affectionately? Push a calf to join the queue? So it is a crime to keep elephants alone!

Colour

The male koel has a shiny coat, the peacock is a vision when it spreads its wings full of “eyes”. Leaf insects sit on green leaves, stick insects look like dry sticks. Brightly-coloured butterflies are either poisonous butterflies.

Big cats merge beautifully with the tall, dry grass. The fennec fox that lives in deserts has a coat in sand-colour. Using the colour of the background to hide is called “concealing colouration.”

Doesn’t the chameleon change colours repeatedly to match its changing habitat?

Chemical marking

The dog sniffs and pees from time to time on the sidewalk to mark its territory. This “chemical communication” is mostly through pheromones (substance released to convey a message) and through body fluids such as urine and venom. Chemical signals can be air-or-waterbone. You see, snakes can “taste” enemies from a distance by using their forked tongues and the roof of their mouth to collect pheromones. Most big cats mark their territory by urinating. Dogs sniff each other’s hindquarters for information. Cats rub their heads against a person or object to release pheromones to say, “You’re mine!”

Auditory

Animal cries signifying danger or distress are now understood well by humans. Sound travels long distances and becomes an effective medium of communication. Almost all animals call – the cuckoo sings to find its mate, doves coo, frogs croak, male crickets chirp to attract and to warn. Female cicadas respond by snapping their wings. Mammals in the oceans, like whales and dolphins, “speak” at ultrasonic frequencies to communicate over long distances, since visibility is poor in water.

 

Picture Credit : Google