Koala An Endangered Australian Tree-Dwelling Marsupial
The Koala is a cuddly, stubby, small tree-dwelling plant-eating marsupial with grey fur, a big black nose and large fluffy ears. It has long arms and legs with very sharp claws which it uses to cling onto trees and branches.
The koala spend almost all of its life in in trees, only coming down to the ground to travel from one tree to another. When on the ground it has a slow awkward walk, but can gallop for the safety of the nearest tree if frightened.
The Koala is a solitary animal. It marks out its home range, an area in which it lives, and rarely ventures out of it. It prefers to live by itself. It doesn't socialise very much with other koalas. It is only during breeding time that they actively seek out other kolas. A mother may, however, have her joey (child) with her.
A Koala's diet consists mainly of eucalyptus leaves. These leaves are highly poisonous to most other animals. These leaves are also hard to digest and low in nutrition. The Koala usually get all the moisture it needs from its food and rarely drinks water.
In keeping with its energy conservation lifestyle, the koala moves slowly, feeds mainly at night and sleeps between 18 to 22 hours each day.
The koala has a very small brain. It occupies only 40% of its cranial cavity and makes up only 0.2% of its body weight (compared to a human’s 1.6%). Scientists believe that the kola’s brain has actually shrunk over evolutionary time as a result of its low energy diet and very safe and sedentary life style.
A male kola lives for about 10 years. The female lives for about 15 years. Koalas are fairly harmless animals. However, if provoked, they can scratch and bite.
The koala was hunted to near extinction in the early 20th century. Only about 100,000 survive in the wild today.
|DID YOU KNOW|
|It is illegal to keep a koala as a pet. Only zoos, scientists and special carers are allowed to keep koalas.|
Koalas vary in size and fur colour depending on where they live in Australia. Those found in the warmer climates of Queensland and northern New South Wales are lighter in colour and significantly smaller than those found furthest to the south in Victoria where it is much colder.
Depending on where it lives an adult male koala can weigh between 5 to 12 kilos and lives for about 10 years. The female koala is about 50% smaller than the male but lives longer, to 15 years or so. The male animal also has a more curved nose than the female.
Koalas don't have a tail.
|DID YOU KNOW|
|Just like each human fingerprint is unique, each koala's finger print is unique and different from that of every other koala.|
The true meaning of the word is now lost. It is sometimes asserted that the word gula meant "no drink". As far as the Dharug language is concerned this is not correct. Many other aboriginal tribes also had names for this animal such as koolawong, colah, karbor, colo, coolbun, boorabee, burroor, bangaroo, pucawan, banjorah, and burrenbong. Some of these words meant "no drink".
The Koala is also sometimes referred to as a 'Koala bear'. But it is not a bear. To further muddy the issue the scientific name Phascolarctos cinereus means "ash coloured pouched bear". All this confusion arose because when the Europeans first arrived in Australia they had never seen marsupials before. When they first saw these animals they thought they were tree climbing bears or even monkeys similar to what they knew back home.
Of course we know now that Koalas are not bears. They are marsupial tree-dwelling mammals. So it's clear. This cuddly little Australian animal is just plain and simply a KOALA.
A male koala is called a buck
The Koala's natural habitats are the eucalyptus forests and woodlands along the eastern seaboard of mainland Australia starting around Townsville in Queensland along the coastal fringe to south-eastern South Australia. Humans have also introduced them to areas around Adelaide in South Australia and some coastal islands such as Kangaroo and French islands. They don't live in dessert or rainforest areas.
The Koala is a solitary territorial animal which hardly socialises with other koalas. It will establish a home range where it will live and feed. Within this home range it will identify a number of favourite feeding trees referred to as home trees. The size of a home range varies according to the density and nutritional quality of the trees of the area. In Queensland, for example where the vegetation is less nutritious, a koala's home range could be as large as 135 hectares. In Victoria on the other hand, where the vegetation is lusher, it could be as little as 1 hectare. A koala's home range may overlap that's of another koala's but it will not visit the home trees of another koala.
The quality of the trees in a given area determines how many koalas can effective live in that area. This is called the carrying capacity of the forest.
The Koala is a tree-dwelling herbivore whose diet is primarily the leaves of eucalyptus trees. It will also eat the leaves of other tree such as the Acacia and Melaleuca. Eucalyptus trees usually grow in low nutrient soils. As a consequence the foliage of these plants are also low in nutrients. The eucalyptus has also adopted a number of defensive mechanisms to make itself less palatable (edible) to herbivores. Its leaves contain high levels of phenols and terpenes which reduce the ability of micro-organism in the intestine to digest leaves; and tannins, phenols, cyanogenic glycosides and essential oils that are toxic. Essential oils are also toxic to digestive bacteria. (This may also be why eucalyptus oil was used as bacterial a disinfectant).
The koala is one of three Australian animals that can eat the poisonous leaves of eucalyptus trees. There is a common myth that koalas are fussy eaters. It is true that the koala eats only 35 out of over 600 types of eucalyptus. This is due more to the toxicity of the plant than the koala's fussiness. The best way to define the koala's eating habits is to the say that it is a "selective eater". The koala uses its highly sensitive nose to pick out only those leaves that are high in nitrogen and low in water, tannins and essential oils. In this way the koala protects itself from being poisoned by its food.
The adult koala is a nocturnal feeder (that is it eats mostly at night). It eats about 400 grams (14oz) of leaves a day. It nips the leaves with it front incisor teeth and chops them with its sharp molar teeth before swallowing. It also has cheek-pouches for storing extra leaves prior to chewing. The koala requires very little water and usually gets all the liquid it needs from the leaves it eats. If necessary it will supplement this with water from tree hollows and on the ground.
The Koala's digestive system is especially adapted to detoxify the poisonous chemicals in its food and to extract as much nutrient as possible. It has a small stomach but a very large cecum which is nearly 1.3 meters long and supports 45 different species of bacteria, some of which are excellent at neutralizing
toxins. It retains its food in its intestine for up to 22 hours to give its digestive system time to break down and absorb as much nutrient as possible.
If you want even more information, here is an excellent scientific paper on the koala's diet .
How a Young Koala is Born
The Koala is a solitary animal that prefers to live by itself. It is only during breeding season, between September and March that it actively seek out brief encounters with other kolas. At this time there is much bellowing and agitation all around. It is at about this time that last year's joeys are weaned away from their mothers and sent off to establish their own home range.
Being a marsupial animal the actual pregnancy is a very short - just 33-35 days. The female gives birth to a single baby koala, called a 'joey'.
This joey is born while at a very early, embryonic, stage of development. It weighs a mere 0.5gms (0.02oz) and looks like a pinkish jelly bean with tiny stumpy limbs. It is about the size of a human thumbnail. About 2 cm (0.05 in) in length.
At this stage the baby joey is hairless, blind and has no ears; but has well-developed sense of smell, forelimbs (arms) and lips. This minuscule living embryo is at its most vulnerable stage of its life. Having exited the mother's birth-canal, using its well-developed sense of smell, the tiny joey uses its strong forelimbs to heave itself up its mother's abdomen and into the safety of her pouch. Once inside the mother's pouch, it attaches itself to a nipple inside the pouch and there it develops into a viable koala.
Unlike a kangaroo's pouch which has its opening at the top, the koala's pouch is located on the centre of its abdomen and has an opening which faces forward. This adaptation is obviously more suitable for a climbing animal such as the koala. As an added safety, in order to prevent the little joey from falling out if its pouch, the koala uses a strong sphincter muscle to keep the entrance of the pouch closed so its baby doesn't accidentally fall out.
As the joey approaches six months, it is finally ready to see the world and starts to peak out of its mother's pouch. While still on drinking milk, the joey also starts to feed on "pap" a special runny jelly-like substance produced by its mother. This substance is sometimes confused as being the mother's faeces or poo. This is not correct. It a substance produced in the mother's caecum and passed out through the mother's rectum. Pap has a vital function in the joey's transition from weaning to leaf eating. Through the pap the mother passes essential gut flora micro-organisms that the joey will need to be able to digest eucalyptus leaves. From about this time the little joey starts to pop its head out of the pouch to nip on eucalyptus leaves as its mother climbs about the trees.
It soon starts clinging onto the mother's underbelly and then when this becomes too difficult it starts to ride on its mother back feeding on leaves as it travels with its mother. It still returns to its mothers pouch for safety and a drink of milk until it finally becomes too big to fit into the pouch. By about the twelfth month, when the mother is ready to breed again, the young joey is weaned from its mother and sets out on its own.
A male koala reaches sexual maturity at about four years. The female in about three years.
|DID YOU KNOW|
The sphincter muscle at the entrance of a koala mother's pouch works a bit like a drawstring on a bag. By tightening the sphincter muscle the koala can control how big the opening of its pouch is.
Koalas before European Settlement
When European settlers first arrived in Australia there was a large koala population in place. Their numbers, however, had been kept in check by the local Aborigines, who hunted them for food.
Koala Number Increase with White Settlement
With European settlement starting in 1778, the Aboriginal populations declined drastically and the Koala no longer had its natural predator (the aborigine hunter) and the population began to grow significantly. Initial small scale hunting of these animals, by the new settlers, took place for their pelts (Europeans didn't seem to like eating Koala meat).
Koalas Slaughter and Skins used for Hats and Gloves
By the mid-nineteenth century as the European settlements grew significantly, a lucrative trade in Koala skins sprung up. Koala hunters shot, poisoned or snared these animals off their tree perches and bludgeoned them to death and sold their skins for export. The main export markets were the US, Canada and Europe where the Koala's soft waterproof fur was used to make hats, gloves and fur linings for coats.
Koala Killed to Near Extinction
The number of Koalas kills is staggering. In 1902 in the state of New South Wales alone 600,000 koala skins were publicly sold. The historian Ellis Troughton has claimed that nearly 2 million koala skins were exported from Australia as recently as 1924. By the late 1920's the Koala was almost extinct. The situation was so dire that they became extinct in the state of South Australia. There were only a few hundred left in New South Wales and a few thousand in Victoria and Queensland.
Koala Saved from Extinction
The wide-scale indiscriminate slaughter of these animals finally lead to huge public outcry. In 1927 Koala hunting was banned throughout Australia. The importation of Koala skins into the US was also banned in 1927 by President Herbert Hoover while he was Secretary of Commerce. Hoover had worked in the gold-fields of Western Australia as a young man and knew fully well of this cuddly little animal. The Koala, nearly extinct, finally got a much needed reprieve. The Koala population has never recovered its earlier numbers. It is estimated that there are approximately 100,000 koalas living in the wild
Koala - Endangered Animal of Australia The Koala is listed as Vulnerable in the Australian Endangered Species List
The major causes of koala decline are listed below.
As with most other native animals the koala suffers from the destruction, fragmentation and loss of its habitat, namely the eucalyptus trees on which it feeds. It is estimated that nearly 80% of Koala habitat has already disappeared. (See the koala on the tree).
Motor Vehicles & Dog Attacks
Motor vehicle strikes and dog attacks account for as many as 4,000 koala fatalities each year. (This lucky koala survived the 80kph impact unscathed).
Forest fires in Australia are fast and intense. The koala being a slow moving animal can't run away from it. It usually seeks shelter by climbing to the top of a tree. Unfortunately eucalyptus trees burn intensely and also are prone to tree-top fires. The story of Sam the Koala captivated the hearts of millions of people from around the world when she was rescued by a fire-fighter in the aftermath of the Black Saturday brushfires of February 2009. (see photo below)
Diseases associated with the chlamydia organism are a serious threat to the koala population.
|Our Other Fascinating Pages|
Aborigines - The First Australians
The Aborigines were the first people to come to Australia...View More