March 31, 2007

Koala bears remind us of the cute stuffed toys, as they are really cute. The koala has no relation to a bear but it is still called koala bear. It is a distant cousin of the wombat. The koala is Australia’s most popular and most loved marsupial mammal.

Usually fully grown koala bears are about two feet long as they are covered with thick, soft grey-brown fur and have round faces; they have saucer-sized ears and long black rubbery looking noses. The koala’s tail is so short that it’s almost invisible, but it does have a tail. Koala bears are normally found naturally only in forests of Australia, as they like to sleep in trees where they can find their favourite tasty eucalyptus leaves. The koala is a nocturnal animal. This means it sleeps during the day in the fork of a tree and eats after dark. Its strong claw allows it to be a strong climber. The Koala moves very slowly and everyone think it is lazy but it’s not like that.

It’s interesting and amazing that koala bears eat eucalyptus leaves and they have to be careful that they don’t eat too much because the acid in it will poison them soon. Other animals can’t digest the oils and poisons in eucalyptus leaves, but the koala’s digestive system has evolved to contain this.

Koalas, together with wombats, their closest relatives, belong to the super-family of vombatoidea. It is believed that some 25 million years ago, they shared a common ancestor. Even today, despite the differences in habits and structure, koalas and wombats have many common anatomical features, pointing to a shared past.

A fully-grown koala eats a little more than one kilogram of leaves a day. Luckily for the koala with such a liking for gum leaves, they are well suited to spend most of their time in trees. Koalas are skilful climbers, getting up the tree trunks by clasping them with the sharp claws of their ‘hands’ and then bringing the hind feet up together in a bounding movement. When walking on a branch koalas grip with the first toe of the hind foot and with the first two digits of the ‘hand’ opposed to the other three. Their long arm and curved claws ensure a firm hold; the vice like grasp between the first two and last three fingers of the hand is even better developed than those of possums.

Koalas may also move about covering quite some distances on the ground, bounding along merrily, using the hind legs in much the same way as they climb or walk quadruped ally. Scientists have debunked this belief.

Koalas do love gum leaves, but these contain no drugs. In fact, only a few species of eucalyptus are suitable for food trees and the koalas need a varied diet from their leaves. Eucalyptus leaves have a very high fibre and low protein content. They contain strong-smelling oils, phenolic compounds and sometimes even cyanide precursors, which make them unpleasant or even poisonous for most mammals.

According to little reliable information about the lifespan of koala bears is 12 plus year; yet in captivity they have been observed to reach the age of 15 years.

Fossil remains of koala-like animals have been found dating back to 25 - 40 million years ago. Koalas, like all Australian animals, are an important part of Aboriginal culture and featured in many myths and legends. John Price was the first European who described koalas in 1798. In 1816, the koala was given its scientific name, phascolarctos cinereus, meaning ash grey pouched bear.

European settlers identified the koala as a source of fur to trade, and millions of koalas were shot for their pelts. By 1924 koalas were extinct in South Australia, severely depleted in New South Wales and estimates for Victoria go as low as 500 animals. The public forced the governments in all states to declare the koala protected species by the late 1930s. Presently, up to 4,000 koalas are being killed each year by cars and dogs.