My Science School

They may look like soft, cuddly teddy bears with their big ears and black button eyes, but koalas are not even remotely related to bears and they are certainly not soft! Their silver-grey fur is similar to the coarse wool of sheep.

Koalas are marsupials, animals that carry their young in a pouch. Marsupials are native to both Australia and the Americas, but the largest number of species is found in Australia, New Guinea and nearly islands.

Found in southeastern and eastern Australia, mainly in Victoria and Queensland, koalas live in eucalyptus forests. Their sole diet consists of leaves from a handful of eucalyptus species. They also live high in the branches of eucalyptus trees, safe from predators who would otherwise find them easy prey because they move so slowly and sleep so much.

Koalas need time to digest their meal. Eucalyptus leaves are poisonous to most animals but koalas have special bacteria in their gut that break down the toxic compounds. They have cheek teeth to help grind the tough leaves. Digestion takes along time since all the nutrients and water have to be extracted from leaves which hardly contain any! This is why koalas sleep almost 20 hours a day and move only if they have to.

Even their bodies are adapted to living in the crooks of branches. They have a barely-there tail, a cushiony, rounded rear end and and a curved spine. Their hands and feet are ideal for clinging to branches, with two opposing thumbs that make for a tight grip. The hands are tipped with sharp claws to dig into the bark. The feet have a long grooming toe and a clawless toe as well that behaves like a thumb!

When a koala baby (called a joey) is born, it is the size of a jelly bean and can’t see or hear. It crawls into the mother’s backward-facing puch and drinks milk from one of two teats. There it remains, warm and safe for six months. The mother also feeds it with her own faeces to give it more immunity.

The joey rides on its mother’s belly and when full-grown, on her back. It becomes independent when a year old.

The male koala’s scent glands are located in a bare patch on his chest. He rubs it on a tree trunk to leave his smell. The scent is made up of 35 different chemicals. The male is smelliest in spring, the mating season!

Today, the koals is listed as vulnerable. It is threatened not only by dogs and being run over by cars, but by habitat loss and disease. There are an estimated 40,000 to 100,000 of these cute animals left in the wild.

 

Picture Credit : Google

Grooming (also called preening) among animals is the art of cleaning and maintaining parts of the body. It is a species-typical behaviour.

Animals groom themselves in many ways – rats lick their bodies, zebras take dust baths, birds preen their feathers, monkeys pick lice from their fur and insects rub their antennae to keep them clean and functional.

Individual animals regularly clean themselves and put their fur, feathers or other skin coverings in good order. This activity is known as personal grooming, a form of hygiene.

Extracting foreign objects such as insects, leaves, dirt, twigs and parasites are all forms of grooming. Among animals, birds spend considerable time preening their feathers. This is done to remove ectoparasites, keep the feathers in good aerodynamic condition, and waterproof them. To do that, they use the preen oil secreted by the uropygial gland, the dust of down feathers, or other means such as dust-bathing or anting. During oil spills, animal conservationists that rescue penguins sometimes dress the in knitted sweaters to stop them from preening and thereby ingesting the mineral oil, which is poisonous.

Cats are well known for their extensive grooming. Cats groom so often that they often produce hairballs from the fur they ingest.

Animals also groom other members of their species (social grooming). The manner of grooming is so typical of a species that it can be used to distinguish it from a closely related one.

Grooming is pre-wired in the brain. If a mouse that is grooming its face with its paw is interrupted in the act, it ‘automatically’ begins to rub the air in front of its face with the other paw! Animals use their head, paws, claws, beak, tongue, etc. for grooming.

Some animals like the starfish have special, pincer-shaped organs called pedicillariae to remove debris from the body surface.

It was earlier believed that animals groomed themselves to maintain hygiene but now it is known that grooming serves many purposes – signaling, courtship, coalition-building and appeasement.

When two mountain rams fight for dominance, the one who loses licks the neck and shoulders of the victor to appease him. The winner may even kneel down to receive he apparent salute.

In a beehive it is essential for all the worker bees to recognize the queen bee’s scent, which assures them of her presence and vitality. A few worker bees pick up the queen’s scent when they groom her by licking her. The workers then move through the nest and contact other workers with their legs, tongues and antennae. Bee-to-bee grooming spreads the queen’s scent quickly and thoroughly.

Many social animals adapt preening and grooming behaviours for other social purposes such as bonding and the strengthening of social structures. Grooming plays a particularly important role in forming social bonds in many primate species, such as chacma baboons and wedge-capped capuchins. Among primates such as chimps, close relations groom one another loyally. This is called allogrooming. On the other hand, outsiders tend to groom members higher up on the social structure.

Grooming apparently gives an animal an advantage that helps in obtaining privileges at a later date.

 

Picture Credit : Google