koala

[Probably from misreading of earlier coola, koolah, from Dharuk gula, gulawan.]

(click to enlarge)
Koala (Phascolarctos cinereus). (credit: Anthony Mercieca — The National Audubon Society Collection/Photo Researchers)

Tree-dwelling marsupial (Phascolarctos cinereus) of coastal eastern Australia. About 24 – 33 in. (61 – 85 cm) long and tailless, the koala has a stout, pale gray or yellowish body; broad face; big, round, leathery nose; small, yellow eyes; and fluffy ears. Its feet have strong claws and some opposable digits. The koala feeds only on eucalyptus leaves. The single offspring remains in the rearward-opening pouch for up to seven months. Koala populations have dwindled seriously, formerly because they were killed for their fur and now because of loss of habitat and the spread of disease.

For more information on koala, visit Britannica.com.

(Phascolarctidae)

Class: Mammalia

Order: Diprotodontia

Family: Phascolarctidae

Thumbnail description
A medium-sized stocky herbivorous marsupial with a bear-like appearance, characterized by a broad face and bulbous nose, large, rounded fluffy ears, relatively long legs with large paws and powerful claws, and a short tail

Size
28–31 in (72–78 cm); 11–26 lb (5.0–11.8 kg)

Number of genera, species
1 genus; 1 species

Habitat
Subtropical/tropical dry eucalypt forest and woodland

Conservation status
Lower Risk/Near Threatened

Distribution
Eastern Australia

Evolution and systematics

The koala family, Phascolarctidae, are believed to have diverged from their nearest marsupial relatives, the wombats, around 24 million years ago (mya). At least six different members of the koala family evolved. The earliest fossil record of a koala was a browser, Perikoala palankarinnica, some 15 mya. More recently, a giant koala, Phascolarctos stirtoni, was a third as large again as our present day koala, but is believed to have died out along with other marsupial megafauna some 40,000 years ago, at around the time that aboriginal hunter-gatherers colonized Australia. Only one species, Phascolarctos cinereus, survives today. Phascolarctos is from the Greek words for "leather pouch" and "bear," while cinereus means "ash-colored."

There are three subspecies of koala, Phascolarctos c. victor, native to the state of Victoria; Phascolarctos c. cinereus, native to New South Wales; and Phascolarctos c. adustus, native to Queensland. Koalas in the north have shorter coats and are smaller than their southern cousins, and genetic studies have confirmed significant differences between the two populations, as well as suggesting that there may be a number of distinct subpopulations in the north. Southern populations appear more homogenous, probably as a result of the numerous translocation projects which have taken place.

The taxonomy for the koala is Phascolarctos cinereus (Gold-fuss, 1817), New South Wales, Australia.

Physical characteristics

The comical, appealing, "teddy bear" appearance of the koala has made it Australia's iconic animal. Despite the misleading popular name "koala bear," koalas are not, of course, related to the omnivorous bear family, but are herbivorous marsupials. They are medium sized, with a head and body length that can be as short as 24 in (60 cm), or as long as 33 in (85 cm), but is usually in the range 28–31 in (72–78 cm). Body weight can also vary considerably, from as little as 8.8 lb (4 kg) for a northern female, to as much as 33 lb (15 kg) for a southern male, but the usual range is 11–26 lb (5.0–11.8 kg). Males are up to 50% larger than females, and there is a significant size difference between koalas in Queensland, where males average 14.3 lb (6.5 kg) and those further south, where males average 26 lb (11.8 kg).

The koala has a compact body with a broad head, large nose, and small eyes. The ears are large and rounded with white edges. Koalas have only a vestigial tail, which is of no assistance in climbing, but they have long, strong limbs, with large paws and sharp claws which are well adapted to grip smooth-barked eucalyts. Fore and hind feet have five digits, all with sharp, recurved claws, except for the first digit of the hind foot, which is short and broad. The first and second digits of the forefeet are opposable to the other three, allowing the animal to grip smaller branches and climb into the outer canopy in search of fresh leaves. The second and third toes of the hind feet are fused, with a double claw.

Koalas do not use dens nor shelters, so their fur is important for insulation. Southern koalas have dense, woolly coats, with thicker, longer fur on the back than the belly. Koalas living further north in warmer subtropical and tropical regions have shorter coats (also lighter in color), sometimes appearing almost naked. The color and pattern of coats varies considerably between individuals and with age, from gray to tawny, with white on the chin, chest, and forelimbs and whitish dappling on the rump. Males have a large chest gland that is used for scent marking trees. Females have a marsupial pouch opening to the rear and containing two teats.

Distribution

Australia's koala population is found in a broad coastal swathe down the eastern seaboard, from the Atherton tablelands in north Queensland to southwestern Victoria. Although this is an area of several hundred thousand square miles (kilometers), deforestation, habitat degradation, and historic persecution mean individual populations within this range are fragmented and often isolated.

Historically, the geographical range of koala populations was broadly similar to today, but extended into South Australia and southern parts of Western Australia. Land clearance and hunting caused populations within this range to contract, and in many cases become extinct. However, intensive koala management and reintroduction programs have reversed this decline in many places, particularly in the south, and koalas are now locally common where suitable habitat survives. A number of localized populations have been re-established in South Australia and Western Australia.

Habitat

Koalas feed almost exclusively on eucalyptus leaves, so their habitat is invariably eucalypt forest and woodland. However, they can tolerate a surprisingly diverse range of environmental and climatic conditions. In the tropical north habitat is often dense thicket, with high year-round temperatures and strong seasonal rainfall. Rainfall is also high in the temperate mountain rainforests of the south, but winters can be much colder. This fertile habitat can support populations as high as three animals per acre (0.4 ha), a stark contrast to the semi-arid open woodland habitat of the west, where a single animal may require 250 acres (100 hectares) to survive.

In temperatures above 77°F (25°C) koalas use evaporative cooling in their airways to regulate temperature, by breathing rapidly, but reduce water loss by decreasing the amount of water in their urine. In cold temperatures koalas, like humans, conserve heat by reducing blood flow to extremities, and have also been seen to shiver, a means of producing heat by rapid muscle contraction.

Behavior

Koalas are essentially solitary animals, with very little social interaction other than during the breeding season. Adults occupy fixed home ranges. Range size depends on the productivity of the environment, but can be as little as 2.5 acres (1 ha) for a male in a fertile habitat, and half that for a female. Within this range an animal may live much of its life in only a dozen favored trees. A dominant adult male's range will overlap the range of up to nine females and a number of subordinate and subadult males.

Within the area of a stable social group individual koalas will "own" a number of food trees and "home range trees" marking the edge of their range. A koala trespassing into an "owned" tree may be aggressively attacked by the resident, but scent markings and scratchings usually warn animals that a tree is under possession. Other trees where ranges overlap will be shared, and it is here that limited social interaction takes place.

Koalas are largely nocturnal, feeding and moving after dusk. They rarely leave the security of the trees, descending to the ground only to move to another food tree, or to consume soil, which aids digestion. Koalas walk on four legs, run with a bounding gait, and can swim if necessary.

As one adaptation to their low-energy eucalyptus leaf diet, koalas sleep up to 20 hours a day, usually wedged comfortably into the fork of a tree. Even when awake, koalas spend much time resting, and feeding occupies only 10% of their day.

Activity livens up in the summer breeding season, when dominant males will attempt to defend their territory for breeding rights with resident females. At this time of year males use their chest gland to scentmark tree trunks and can often be heard bellowing, apparently to warn off rival males and attract females. This deep, grunting bellow often provokes responses from other males in the area. At night males move around more, fighting with any competing adult males that they encounter, or mating with estrous females.

Koalas have a range of other sounds for communication. Mothers and babies make soft clicking, squeaking sounds, and gentle murmuring, or will grunt if annoyed. All koalas are capable of a distressing, high-pitched cry like a screaming baby when afraid.

Feeding ecology and diet

Australia has some 650 species of eucalypt, but koalas are choosy eaters, and feed on only around 30 species, with just a handful, including river red gum, gray gum and manna gum, preferred. They have occasionally been known to eat noneucalypt leaves, including acacia, mistletoe and box. Koalas eat about 1.3 to 1.8 lb (600 to 800 g) of leaves a day.

Koalas reach their food by climbing high up smooth, vertical eucalypt trunks, gripping with their sharp foreclaws and using their powerful front legs to pull themselves up, while bringing their hind legs up to their front. Although they generally move slowly and laboriously to conserve energy, they are capable of surprising agility and can leap 6 ft (2 m) from trunk to trunk.

Eucalyptus leaves are low in nutrients, contain a large proportion of indigestible cellulose and lignin, and are full of toxic chemicals. Koalas have evolved a number of ways to cope with this poor diet. They avoid the most toxic species, and vary their choice of food tree throughout the year as toxin levels vary seasonally in some species. The koala's liver is capable of detoxifying and excreting some poisonous compounds from those species they do eat. Koalas have large cheek pouches, to handle large amounts of poor quality forage, and well-developed teeth, which include a single premolar and four molars in each jaw, which grind the fibrous leaves to a fine paste. This is then digested by microbial fermentation in the animal's unusually long cecum (a blind sac in the digestive tract, between the junction of the small and large intestines). A koala's cecum can be more than 75 in (2m) long.

The low energy yield of the koala's diet explains their slow, sedentary lifestyle. However, it is a myth that koalas are drugged by the poisonous compounds in eucalyptus leaves. What is true is that koala have one of the smallest brains of all marsupials relative to body size—only 0.2% of body weight—and this has been explained as a further response to diet, since the brain is one of the most energy-consuming of the body's organs.

Koalas obtain most of their water from leaves, but occasionally drink at streams, and in captivity often choose to drink fresh water.

Reproductive biology

Koalas are polygynous. During the summer breeding season a dominant male will attempt to mate with any estrous females he encounters in his range. Copulation lasts only a couple of minutes, with the male mounting the female from behind and holding her against a branch. Females are sexually mature at two years old, but generally do not start to breed until they are older—full physical maturity is reached at about four years old in females, five years old in males.

Females have an estrous cycle of about 30 days, and usually breed once every year, between November and March. Gestation lasts about 35 days before a single young (very rarely twins) is born, weighing less than 0.02 oz (0.5g) and measuring about 2 cm long.

The tiny newborn koala crawls into the mother's large pouch and attaches itself to one of the two teats. By 13 weeks the young joey will have grown to about 2 oz (50 g), and by 22 weeks its eyes open and it begins to poke its head out of the pouch for the first time. Joeys have a pouch life of five to seven months, after which they spend most of their time out of the pouch, clinging to the mother's belly and later sitting on their back. Joeys are weaned at six to 12 months, but towards the end of their pouch life also feed regularly on soft, partially-digested leaf material passed through the mother's digestive tract. This "pap," which contains a high concentration of microorganisms, is believed to be important in introducing to the young koala's gut the microbes it will need to digest eucalyptus leaves.

A joey will remain with its mother until about one year old, when it weighs around 4.4 lb (2 kg) and can begin to fend for itself. Juveniles disperse to find their own home range at about two years old, searching for another breeding group to join, but becoming nomadic if no area is available.

Koalas can live in excess of 10 years in the wild, and 17 years or more in captivity. Longevity is probably related to stress factors such as habitat pressure, disease, and human interference.

Conservation status

Koala conservation is a complex issue. Populations are under severe pressure from habitat loss in many parts of Australia, yet in some areas the koala is common or even over populous.

Before 1900 koalas numbered in the millions, despite regularly suffering enormous losses to bushfires and disease epidemics. But in the first decades of the twentieth century extensive forest clearance and large scale hunting for the koala's warm, cheap, durable fur saw populations crash. The slaughter reached a peak in 1924, when over two million koala pelts were exported to Europe and America, and by the end of that year the species had been exterminated in South Australia and nearly wiped out in Victoria and New South Wales. A healthy population surviving in Queensland was next to suffer when in 1927 the state government bowed to commercial pressure and allowed an open season—600,000 more skins were exported.

Public outcry in Australia and abroad eventually resulted in legal protection, and since the 1920s intensive conservation measures, including captive breeding and translocation efforts, have allowed populations to partially recover. Today koalas are still under intense pressure in many parts of their range, but are not classified as threatened. The Australian government lists koalas as vulnerable, but has not put them on the country's endangered list. The World Conservation Union (IUCN) classifies koalas as Lower risk/Near Threatened, and lists habitat loss and degradation due to timber felling and urbanization, and human disturbance, particularly through fire, as the major threats.

Unfortunately, koalas inhabit precisely those eastern seaboard regions of Australia that are seeing most rapid urbanization and agricultural development. In the past 200 years an estimated one-third of Australia's eucalyptus forest has disappeared, and in semi-arid parts of Queensland, thousands of acres of woodland are still being cleared for agricultural use every year. Urbanization and tourist development along the coastal strip is further fragmenting eucalyptus woodlands. Bush fires caused by negligence or arson account for thousands of deaths each year, while an estimated 10,000 koalas are killed in road accidents. Koalas put up no resistance to attacks from domestic dogs, and do not cope well with stress, having abnormally small adrenal glands. There is also evidence that inbreeding in isolated, fragmentary populations is leading to physical abnormalities.

Despite all these pressures, there are actually locations where koala populations have thrived to such an extent that they are causing environmental damage. Koalas were translocated to a number of islands where they were not found naturally as long ago as the 1870s. Populations on Phillip and French Islands in Victoria, and Kangaroo Island in South Australia have grown so large that the unpalatable prospect of culling has been proposed. Thousands of animals have been relocated back to the mainland, causing similar overcrowding problems in some locations, and contraception is being investigated as a more publicly acceptable alternative to culling.

One possible explanation for these overpopulation problems is that the island populations are free of chlamydia, a disease that is now thought to have been endemic in koalas for many years, and may have acted as a natural population control, remaining benign when conditions were good, but killing off weaker animals during stressful times such as when habitat is reduced.

Some koala conservation work, including purchase of land for protected reserves, is being carried out by state authorities, but much koala conservation and research is in the hands of charities and privately-run welfare organizations. The koala's cute and cuddly appeal helps raise funding for such non-government organizations.

One problem in planning conservation management is the difficulty in obtaining accurate population figures. The Australian Koala Foundation suggests numbers have dropped from 400,000 in the mid-1980s to between 40,000 and 80,000 today, but this estimate can only be an educated guess. The Foundation is compiling a national atlas of surviving koala habitats, which will provide a tool to lobby for habitat conservation.

Significance to humans

The name koala is believed to have originated from Aboriginal dialect names for the animal, which include cullewine, koolewong, colo, colah, and koolah. One suggested translation for these Aboriginal names is "no water," referring to the koala's ability to largely subsist on moisture from leaves.

Australia's Aboriginal people have long hunted koalas for food—they make a slow-moving target easy to hit with a boomerang. But traditional Dreamtime stories teach Aborigines that if they fail to respect the animal they will be visited by a terrible drought. Tradition dictates that while koalas may be eaten, they must not be skinned nor their bones broken.

No such respect was accorded by early European settlers who shot koalas for "sport" and later for fur. Today koalas have a different, but equally important commercial significance, as animal ambassadors for the tourist trade. So important is the koala as a tourist draw card, particularly to the important Japanese market, that moves by state governments to ban "koala cuddling" on the grounds that it is stressful for the animals, were opposed (unsuccessfully) by tourist authorities.

Where populations are healthy wild koalas are easy to observe, but most tourists see koalas in zoos and animal sanctuaries, where petting, if not cuddling, is allowed. The Australian federal government strictly controls exports of live koalas, and this, combined with the problems of satisfying the koala's very specific dietary requirements, mean there are only a handful of zoos outside Australia, in the United States, Japan, Germany, and Taiwan, where koalas are exhibited.

Resources

Australian Koala Foundation. Proceedings of a Conference on the Status of the Koala in 2000, Incorporating the Ninth National Carers Conference—Noosa, QLD. Brisbane: Australian Koala Foundation, 2000.

Lyons, K., A. Melzer, F. Carrick, and D. Lamb, eds. The Research and Management of Non-urban Koala Populations. Rockhampton: Koala Research Centre of Central Queensland, 2001.

Martin, R. W., and K. A. Handasyde. The Koala: Natural History, Conservation and Management. Sydney: University of New South Wales Press, 1999.

Saunders, N. R., and L. Hinds, eds. Marsupial Biology: Recent Research, New Perspectives. Sydney: University of New South Wales Press, 1997.

Strahan, R., ed. The Mammals of Australia Sydney: New Holland Publishers, 1998.

Clark, T., N. Mazur, S. Cork, S. Dovers, and R. Harding. "Koala Conservation Policy Process: Appraisal and Recommendations." Conservation Biology 14, no. 3 (2000): 681–690.

Ellis, W. A, P. T. Hale, and F. Carrick. "Breeding Dynamics of Koalas in Open Woodlands." Wildlife Research 29 (2002): 19–25.

Martin, R. W. "Managing Overabundance in Koala Populations in South-eastern Australia: Future Options." Australian Biologist 10, no. 1 (1997): 57–63.

Moore, B. D., and W. J. Foley. "A Review of Feeding and Diet Selection in Koalas (Phascolarctos cinereus)" Australian Journal of Zoology 48 (2000): 317–333.

Australian Koala Foundation. Level 1, 40 Charlotte Street, Brisbane, Queensland 4001 Australia. Phone: (7) 3229 7233. Fax: (7) 3221 0337. E-mail: akf@save the koala.com Web site:

[Article by: Stephen and; Ann Toon]

A single species, Phascolarctos cinereus, which is a member of the family Phalangeridae in the mammalian order Marsupialia (pouch-bearing animals). It is a small animal that weighs from 11 to 17 lb (5 to 8 kg) when mature. They are restricted to eastern Australia. Not only do they have a specialized diet of eucalyptus leaves, but the leaves must be of a certain age from a specific species of tree, and the tree must grow upon a certain type of soil.

The koala breeds once each season, and the usual number of offspring is one. It remains in the pouch for 6 months; then it clings to the back of its mother and is carried around in this manner until 1 year old. See also Mammalia; Marsupialia.

A small (10 to 15 lb) bear-like, marsupial creature of the family Phascolarctidae. The baby koala is very small when born and is subsequently carried in the mother's pouch and later on her back. Called also Phascolarctos cinereus.

Tutor's tip: A "coaler" is a ship that transports coal, a "cola" is a carbonated soft drink, the "colla" is the neck or necklike bones, a "koala" is a bearlike animal found in Australia, while a "kola" is a type of tree found in Africa.

This article is about the Australian marsupial. For other uses, see Koala (disambiguation).

Koala[1]
female
male
Conservation status
Least Concern (IUCN 3.1)[2]
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Diprotodontia
Family:	Phascolarctidae
Genus:	Phascolarctos
Species:	P. cinereus
Binomial name
Phascolarctos cinereus (Goldfuss, 1817)

The koala (Phascolarctos cinereus) is a thickset arboreal marsupial herbivore native to Australia, and the only extant representative of the family Phascolarctidae.

The koala is found in coastal regions of eastern and southern Australia, from near Adelaide to the southern part of Cape York Peninsula. Populations also extend for considerable distances inland in regions with enough moisture to support suitable woodlands. The koalas of South Australia were largely exterminated during the early part of the 20th century, but the state has since been repopulated with Victorian stock. The koala is not found in Tasmania or Western Australia.

Contents 1 Names 2 Variation 3 Physical description 4 Life cycle 5 Diet and behaviour 6 Conservation status 7 See also 8 References 9 External links

Names

The word koala comes from the Dharuk gula. Although the vowel /u/ was originally written in the Latin alphabet as "oo" (in spellings such as coola or koolah), it was changed to "oa" possibly due to an error.^[3] The word is erroneously said to mean "doesn't drink".^[3]

The scientific name of the koala's genus, Phascolarctos, is derived from Greek phaskolos "pouch" and arktos "bear". Its species name, cinereus, is Latin and means "ash-coloured".^[4]

Although the koala is not a bear, English-speaking settlers from the late 18th century first called it koala bear due to its similarity in appearance to bears. Although taxonomically incorrect, the name koala bear is still in use today outside Australia^[5] — its use is discouraged because of the inaccuracy in the name.^{[6][7][8][9][10]} Other descriptive English names based on "bear" have included monkey bear, native bear, and tree-bear.^[3]

Variation

A Southern koala on Kangaroo Island, not native to the island

Although three subspecies have been described, these are arbitrary selections from a cline and are not generally accepted as valid. Following Bergmann's Rule, southern individuals from the cooler climates are larger. A typical Victorian koala (formerly P. cinereus victor) has longer, thicker fur, is a darker, softer grey, often with chocolate-brown highlights on the back and forearms, and has a more prominently light-coloured ventral side and fluffy white ear tufts. Typical and New South Wales koala weights are 12 kg (26 lb) for males and 8.5 kg (19 lb) for females. In tropical and sub-tropical Queensland, however, the koala is smaller (at around 6.5 kg (14 lb) for an average male and just over 5 kg (11 lb) for an average female), a lighter often rather scruffy grey in colour, and has shorter, thinner fur. In Queensland, the koala was previously classified as the subspecies P. cinereus adustus, and the intermediate forms in New South Wales as P. cinereus cinereus. A fourth variation, though not technically a subspecies, is Phascolarctos cinereus aurum, or in English "golden koala," which has a slight golden tinge to the fur as a result of an absence of the melanin pigment that produces albinism in most other mammalian species. The variation from one form to another is continuous and there are substantial differences between individual koalas in any given region such as hair colour. The origins of the koala are unclear, although almost certainly they descended from terrestrial wombat-like animals. Koala fossils are quite rare, but some have been found in northern Australia dating to 20 million years ago. During this time, the northern half of Australia was rainforest. The koala did not specialise in a diet of eucalyptus until the climate cooled and eucalypt forests grew in the place of rainforests. The fossil record indicates that before 50,000 years ago, giant koalas inhabited the southern regions of Australia. The koala fills the same ecological role as the sloth of South America.

Physical description

Koalas have a slow metabolism and sleep for most of the day

The koala is broadly similar in appearance to the wombat (its closest living relative),^[1] but has a thicker coat, much larger ears, and longer limbs. The koala has large, sharp claws to assist with climbing tree trunks. Weight varies from about 14 kg (31 lb) for a large southern male, to about 5 kg (11 lb) for a small northern female. The koala's five fingers are arranged with opposable thumbs, providing better gripping ability. The first two fingers are positioned in apposition on the front paws, and the first three fingers for the hind paws.^[11] The koala is one of the few mammals (other than primates) that has fingerprints. Koala fingerprints are similar to human fingerprints; even with an electron microscope, it can be quite difficult to distinguish between the two.^[12]

The teeth of the koala are adapted to their herbivorous diet, and are similar to those of other diprotodont marsupials, such as kangaroos and wombats. They have sharp incisors to clip leaves at the front of the mouth, separated from the grinding cheek teeth by a wide diastema. The dental formula for koalas is:

Dentition
3.1.1.4
1.0.1.4

The male koala, like many marsupials, has a bifurcated penis. The female has two lateral vaginas and two separate uteri, which is common to all marsupials.^[13]

Koala walking along a branch. Koalas also walk on all four legs when walking on the ground

The brain in the ancestors of the modern koala once filled the whole cranial cavity, but has become drastically reduced in the present species, a degeneration scientists suspect is an adaptation to a diet low in energy.^[14] One of the smallest in marsupials with no more than 0.2% of its body weight,^[15] about 40% of the cranial cavity is filled with cerebrospinal fluid, while the brain's two cerebral hemispheres are like "a pair of shrivelled walnut halves on top of the brain stem, in contact neither with each other nor the bones of the skull. It is the only animal on Earth with such a strangely reduced brain."^[16]

It is generally a silent animal, but males have a very loud advertising call that can be heard from almost a kilometre away during the breeding season. When under stress, koalas may issue a loud cry, which has been reported as similar to that of a human baby.^[17] There is little reliable information about the lifespan of the koala, but in captivity they have been observed to reach the age of 18 years.^[11]

Life cycle

A young joey, preserved at Port Macquarie Koala Hospital

Baby koala at Currumbin Wildlife Sanctuary

Females reach maturity at 2 to 3 years of age, males at 3 to 4 years. A healthy female koala can produce one young each year for about 12 years. Gestation is 35 days. Twins are very rare; the world's first confirmed identical twin koalas, named "Euca" and "Lyptus", were born at the University of Queensland in April, 1999.^[18][19] Mating normally occurs between December and March, the Southern Hemisphere's summer.

A baby koala is referred to as a joey and is hairless, blind, and earless. At birth the joey, only a quarter of an inch long, crawls into the downward-facing pouch on the mother's belly (which is closed by a drawstring-like muscle that the mother can tighten at will) and attaches itself to one of the two teats.

Young remain hidden in the pouch for about six months, only feeding on milk. During this time they grow ears, eyes, and fur. The joey then begins to explore outside of the pouch. At about this stage it begins to consume small quantities of the mother’s "pap" (formerly thought to be excrement, but now thought to come from the mother's cecum) in order to inoculate its gut with the microbes necessary to digest eucalypt leaves.^[20] The joey will remain with its mother for another six months or so, riding on her back, and feeding on both milk and eucalypt leaves until weaning is complete at about 12 months of age. Young females disperse to nearby areas at that time; young males often stay in the mother's home range until they are two or three years old.

Diet and behaviour

Koala with young

Koala dozing during the day

The koala lives almost entirely on eucalypt leaves. This is likely to be an evolutionary adaptation that takes advantage of an otherwise unfilled ecological niche, since eucalypt leaves are low in protein, high in indigestible substances, and contain phenolic and terpene compounds that are toxic to most species. Like wombats and sloths, the koala has a very low metabolic rate for a mammal and rests motionless for about 16 to 18 hours a day, sleeping most of that time. Koalas can be aggressive towards each other, throwing a foreleg around their opponent and biting, though most aggressive behavior is brief squabbles.^[21] Handling koalas may cause them stress,^[22] and the issue of aggression and stress from handling is a political issue in Australia.^[23][24]

Koalas spend about three of their five active hours eating. Feeding occurs at any time of day, but usually at night. Koalas eat an average of 500 g (18 oz) of eucalypt leaves each day, chewing them with powerful jaws to a very fine paste before swallowing. The liver deactivates the toxic components ready for excretion, and the hind gut (especially the caecum) is greatly enlarged to extract the maximum amount of nutrient from the poor quality diet. Much of this is done through bacterial fermentation: while young are being weaned, the mother passes these essential digestive aids on to her offspring.

A koala eating eucalyptus

Koala in tree, scratching & grooming

The koala will eat the leaves of a wide range of eucalypts, and occasionally even some non-eucalypt species such as Acacia, Leptospermum, and Melaleuca. It has firm preferences for particular varieties of eucalypt and these preferences vary from one region to another: in the south Manna Gum, Blue Gum, and Swamp Gum are favoured; Grey Gum and Tallowwood are important in the north, and the ubiquitous River Red Gum of the isolated seasonal swamps and watercourses that meander across the dry inland plains allows the koala to live in surprisingly arid areas. Many factors determine which of the 680 species of eucalypt trees the koala eats. Among trees of their favourite species, however, the major factor that determines which individual trees the koala chooses is the concentration of a group of phenolic toxins called formylated phloroglucinol compounds.

Conservation status

The Australian Government currently lists the koala as a priority species for conservation status assessment.^[25] Government estimates of the national koala population numbers in the hundreds of thousands, although other studies have estimated as few as 80 000 koalas left in the wild.^[26] The Australian Koala Foundation estimates there are around 100,000 koalas left in the wild.^[27]

The IUCN lists the species as "Least Concern".^[2] The Australian government does not consider the species to be threatened, although the US government has declared the koala a threatened species.^[28]

The koala inhabits four Australian states. Under state legislation, the species is listed as:

• Queensland — Common, or "Least Concern Wildlife" throughout the state, except in the South East Queensland bioregion, where it is listed as vulnerable.^[29]
• New South Wales — listed at a state scale as vulnerable, but varying regionally from secure to locally extinct.^[30]
• South Australia — classified as rare.^[31]
• Victoria — The koala population in Victoria was considered large and thriving, according to an article which was last reviewed on 29 October, 2007.^[32] However, the koala population classification in Victoria may now have changed, due to the Black Saturday bushfires.^[33][34]

The koala was hunted almost to extinction in the early 20th century,^[35] largely for its fur. Millions of furs were traded to Europe and the United States, and the population has not fully recovered from such decimations. Extensive cullings occurred in Queensland in 1915, 1917, and again in 1919 when over one million koalas were killed with guns, poisons, and nooses.^[36] The public outcry over the cullings was most likely the first wide-scale environmental issue that rallied Australians.^[36] Despite the growing movement to protect native species, the poverty brought about by the drought of 1926–28 led to another 600,000 koalas being killed during a one-month open season in August 1927.^[36]

Today, habitat loss and the impacts of urbanisation (such as dog attacks and traffic accidents) are the leading threats to the survival of the koala. In recent years, some colonies have been hard hit by disease, especially chlamydia. The koala requires large areas of healthy, connected forest and will travel long distances along tree corridors in search of new territory and mates. The increasing human population of the coastal parts of the continent continues to cut these corridors by agricultural and residential development, forestry, and road-building, marooning koala colonies in decreasing areas of bush. The long term viability of the koala is therefore threatened by genetic weakness^{[citation needed]}. The Australian Koala Foundation is the principal organisation dedicated to the conservation of the koala and its habitat, mapping 40,000 km² (15,000 sq mi) of land for koala habitat and claiming strong evidence that wild koala populations are in serious decline throughout the species natural range.^[37]

Although the species covers a large area, only 'pieces' of koala habitat remain. Presently, many habitats are lost to weeds, clearance for agriculture, or carved up by developers. Other threats come from logging, poor management, attacks from feral and domestic animals, diseases, and roads.

In contrast to the situation on much of the mainland, where populations are declining,^[37] koalas, like many other species, can overrun smaller islands or isolated regions where they have been introduced.^[38] On Kangaroo Island in South Australia, koalas introduced some 90 years ago have thrived in the absence of predators and competition. Combined with an inability to migrate to new areas, this has caused the koala populations to become unsustainable and threaten the island's unique ecology. In particular, species of Manna Gum, native to the island, are being stripped by koalas at a rate faster than they can regenerate, endangering local birds and invertebrates that rely on them, and causing the extinction of at least one isolated population of manna. Koala numbers are estimated at over 30,000^{[citation needed]}, with ecologists suggesting that the island can sustain 10,000 at most^{[citation needed]}. Although culling has been suggested as a means to reduce koala numbers, with the South Australian government seriously considering such in 1996, this has met with fierce opposition both domestically and internationally, and the species remains protected. The popularity of the koala has made the possibility of a cull politically improbable, with any negative perception likely to impact tourism and a government's electability. In place of a cull, sterilization and relocation programs have had only limited success in reducing numbers thus far, and remain expensive. There is evidence that koalas relocated to the mainland have difficulty establishing themselves in the different circumstances. A mooted alternative to the complex sterilization method, wherein the animal must first be captured, are hormonal implants that can be injected via darts.

As with most native Australian animals, the koala cannot legally be kept as a pet in Australia or anywhere else. The only people who are permitted to keep koalas are wildlife carers and, occasionally, research scientists. These individuals are issued with special permits to care for koalas, but have to return them to the wild when they are either well enough or, in the case of joeys, old enough.^[9]

See also

• Fauna of Australia
• Koala emblems and popular culture
• List of monotremes and marsupials

References

1. ^ ^{a b} Groves, C. (2005). Wilson, D. E., & Reeder, D. M.. ed. Mammal Species of the World (3rd ed.). Johns Hopkins University Press. pp. 43. ISBN 0-801-88221-4. http://www.bucknell.edu/msw3/browse.asp?id=11000005. 
2. ^ ^{a b} Gordon G, Menkhorst P, Robinson T, Lunney D, Martin R. & Ellis M (2008). Koala. In: IUCN 2008. IUCN Red List of Threatened Species. Downloaded on 2008-10-30.
3. ^ ^{a b c} Dixon, R.M.W.; Moore, Bruce; Ramson, W. S.; Thomas, Mandy (2006). Australian Aboriginal Words in English: Their Origin and Meaning (2nd ed.). South Melbourne: Oxford University Press. ISBN 0-19-554073-5. 
4. ^ Kidd, D.A. (1973). Collins Latin Gem Dictionary. London: Collins. p. 53. ISBN 0-00-458641-7. 
5. ^ Leitner, Gerhard; Sieloff, Inke (1998). "Aboriginal words and concepts in Australian English". World Englishes 17 (2): 153–169. doi:10.1111/1467-971X.00089. 
6. ^ www.ferngallery.com. "Australian Koala Foundation". Savethekoala.com. http://www.savethekoala.com/koalasfacts.html. Retrieved 2009-03-09. 
7. ^ "Australian Fauna". Australian Fauna. http://www.australianfauna.com/koala.php. Retrieved 2009-03-09. 
8. ^ "Australasian Regional Association of Zoological Parks and Aquaria". Arazpa.org.au. http://www.arazpa.org.au/Koala/default.aspx. Retrieved 2009-03-09. 
9. ^ ^{a b} Australian Koala Foundation. "Frequently asked questions (FAQs)". https://www.savethekoala.com/koalasfaqs.html. 
10. ^ Australian Koala Foundation. "Interesting facts about koalas". https://www.savethekoala.com/koalasfacts.html. 
11. ^ ^{a b} Martin, Roger (1984). Macdonald, D.. ed. The Encyclopedia of Mammals. New York: Facts on File. pp. 872–875. ISBN 0-87196-871-1. 
12. ^ Henneberg, Maciej; Lambert, Kosette M., Leigh, Chris M. (1997). "Fingerprint homoplasy: koalas and humans". NaturalSCIENCE.com 1. http://naturalscience.com/ns/articles/01-04/ns_hll.html. 
13. ^ Dawson, T.J.; Finch, E., Freedman, L., Hume, I.D., Renfree, M., Temple-Smith, P.D. (PDF). Fauna of Australia; 17. Morphology and Physiology of Metatheria. pp. 51, 53. http://www.environment.gov.au/biodiversity/abrs/publications/fauna-of-australia/pubs/volume1b/17-ind.pdf. 
14. ^ "PLAY'S the THING | Natural History | Find Articles at BNET". Findarticles.com. 1999-07-01. http://findarticles.com/p/articles/mi_m1134/is_6_108/ai_55127881. Retrieved 2009-03-09. 
15. ^ "Koala (Phascolarctos cinereus) Fact Sheet 2003". Spot.colorado.edu. http://spot.colorado.edu/~humphrey/fact%20sheets/koala/koala.htm. Retrieved 2009-03-09. 
16. ^ Flannery, T.F. (1994). The Future Eaters: An ecological History of the Australasian Lands and People. Sydney: Reed New Holland. p. 86. 
17. ^ "Facts about Koalas". Koalaplayworld.com. http://koalaplayworld.com/Facts_about_Koalas.html. Retrieved 2009-03-09. 
18. ^ http://www.koalaresearch.net.au/General.html
19. ^ "University of Queensland Koala Study program". Koalas.cqu.edu.au. http://koalas.cqu.edu.au/news/baby.htm. Retrieved 2009-03-09. 
20. ^ Martin, Roger; Handasyde, Kathrine Ann (1999). The Koala: Natural History, Conservation and Management. Australian Natural History Series (2nd ed.). UNSW Press. pp. 64–65. ISBN 0868405442. 
21. ^ Smith, M (1980). "Behaviour of the Koala, Phascolarctos cinereus (Goldfuss), in Captivity VI*. Aggression". Australian Wildlife Research 7 (2): 177 - 190. http://www.publish.csiro.au/paper/WR9800177.htm. 
22. ^ Jackson, Stephen M. (2003). "Koalas". Australian mammals: biology and captive management. CSIRO Publishing. pp. 524. ISBN 0643066357. http://books.google.co.uk/books?id=Ys_NC1P9AX4C&pg=PA161. 
23. ^ "Koalas Welfare - 16/11/1995 - ADJ - NSW Parliament". Parliament.nsw.gov.au. http://www.parliament.nsw.gov.au/prod/parlment/HansArt.nsf/66662d17d79b79d7ca256cfd000e0c22/ca256d11000bd3aa4a25644a00824515!OpenDocument. Retrieved 2009-03-09. 
24. ^ Anderson, Ian (2 December 1995). "Please don't cuddle the koalas". New Scientist. http://www.newscientist.com/article/mg14820060.800-please-dont-cuddle-the-koalas.html. Retrieved 2009-10-21. 
25. ^ Australian Government. "Environmental Finalised Priority Assessment List for the Assessment Period Commencing 1 October 2008" (PDF). http://www.environment.gov.au/biodiversity/threatened/publications/pubs/priority-assessment-list.pdf. 
26. ^ Australian Government. "Environmental assessment of koala's conservation status". http://www.environment.gov.au/minister/env/2006/mr14july206.html. 
27. ^ Australian Koala Foundation. "Potential Koala Habitat in 2008". https://www.savethekoala.com/kc/maplaunch2008.html. 
28. ^ US Fish and Wildlife Service. "Threatened and Endangered Species System". http://ecos.fws.gov/tess_public/SpeciesReport.do. 
29. ^ Queensland Parks and Wildlife Service. "EPA/QPWS Koala designation". http://www.epa.qld.gov.au/nature_conservation/wildlife/koala_plan/. 
30. ^ New South Wales Parks and Wildlife Service. "NSWPWS Koala designation" (PDF). http://www.nationalparks.nsw.gov.au/pdfs/tsprofile_koala.pdf. ^{[dead link]}
31. ^ Australian Koala Foundation. "Koala conservation status (FAQs)". https://www.savethekoala.com/koalasendangered.html. 
32. ^ Department of Sustainability and the Environment. "Victorian Koala designation". http://www.dse.vic.gov.au/dse/nrenpa.nsf/LinkView/E260BBD07DD52CF4CA256DE3007F11443B3BE6168C8BE71ECA256E5A0010BD5C. 
33. ^ Helping Koalas burnt in the bushfires
34. ^ "Koala — Foundation National Parks and Wildlife". Fnpw.org.au. 2009-03-02. http://www.fnpw.org.au/OurProjects/Plants_Wildlife/Koala.htm. Retrieved 2009-03-09. 
35. ^ Australian Koala Foundation. "History of Koalas". https://www.savethekoala.com/koalashistory.html. 
36. ^ ^{a b c} Evans, Raymond (2007). A History of Queensland. Port Melbourne, Victoria: Cambridge University Press. p. 168. ISBN 9780521876926. 
37. ^ ^{a b} Australian Koala Foundation. "Koalas - Endangered or Not?". https://www.savethekoala.com/koalasendangered.html. 
38. ^ "Koalas Overrunning Australia Island "Ark"". News.nationalgeographic.com. http://news.nationalgeographic.com/news/2002/05/0510_020510_TVkoala.html. Retrieved 2009-03-09. 

External links

Wikimedia Commons has media related to: Koala

Wikispecies has information related to: Phascolarctos cinereus

• Australian Koala Foundation
• Lone Pine Koala Sanctuary
• The Koala

v • d • e Extant Diprotodontia species Kingdom Animalia · Phylum Chordata · Class Mammalia · Infraclass Marsupialia   Suborder Vombatiformes Phascolarctidae Phascolarctos Koala (P. cinereus) Vombatidae (Wombats) Vombatus Common Wombat (V. ursinus) Lasiorhinus Southern Hairy-nosed Wombat (L. latifrons) · Northern Hairy-nosed Wombat (L. krefftii)   Suborder Phalangeriformes (Possums) (cont. below) Phalangeridae (including Cuscuses) Ailurops (Bear cuscuses) Talaud Bear Cuscus (A. melanotis) · Sulawesi Bear Cuscus (A. ursinus) Phalanger Gebe Cuscus (P. alexandrae) · Mountain Cuscus (P. carmelitae) · Ground Cuscus (P. gymnotis) · Eastern Common Cuscus (P. intercastellanus) · Woodlark Cuscus (P. lullulae) · Blue-eyed Cuscus (P. matabiru) · Telefomin Cuscus (P. matanim) · Southern Common Cuscus (P. mimicus) · Northern Common Cuscus (P. orientalis) · Ornate Cuscus (P. ornatus) · Rothschild's Cuscus (P. rothschildi) · Silky Cuscus (P. sericeus) · Stein's Cuscus (P. vestitus) Spilocuscus Admiralty Island Cuscus (S. kraemeri) · Common Spotted Cuscus (S. maculatus) · Waigeou Cuscus (S. papuensis) · Black-spotted Cuscus (S. rufoniger) · Blue-eyed Spotted Cuscus (S. wilsoni) Strigocuscus Sulawesi Dwarf Cuscus (S. celebensis) · Banggai Cuscus (S. pelegensis) Trichosurus (Brushtail possums) Northern Brushtail Possum (T. arnhemensis) · Short-eared Possum (T. caninus) · Mountain Brushtail Possum (T. cunninghami) · Coppery Brushtail Possum (T. johnstonii) · Common Brushtail Possum (T. vulpecula) Wyulda Scaly-tailed Possum (W. squamicaudata) Burramyidae (Pygmy possums) Burramys Mountain Pygmy Possum (B. parvus) Cercartetus Long-tailed Pygmy Possum (C. caudatus) · Southwestern Pygmy Possum (C. concinnus) · Tasmanian Pygmy Possum (C. lepidus) · Eastern Pygmy Possum (C. nanus)   Suborder Phalangeriformes (Possums) (cont. above) Tarsipedidae Tarsipes Honey Possum (T. rostratus) Petauridae Dactylopsila Great-tailed Triok (D. megalura) · Long-fingered Triok (D. palpator) · Tate's Triok (D. tatei) · Striped Possum (D. trivirgata) Gymnobelideus Leadbeater's Possum (G. leadbeateri) Petaurus Northern Glider (P. abidi) · Yellow-bellied Glider (P. australis) · Biak Glider (P. biacensis) · Sugar Glider (P. breviceps) · Mahogany Glider (P. gracilis) · Squirrel Glider (P. norfolcensis) Pseudocheiridae Hemibelideus Lemur-like Ringtail Possum (H. lemuroides) Petauroides Greater Glider (P. volans) Petropseudes Rock-haunting Ringtail Possum (P. dahli) Pseudocheirus Common Ringtail Possum (P. peregrinus) Pseudochirulus Lowland Ringtail Possum (P. canescens) · Weyland Ringtail Possum (P. caroli) · Cinereus Ringtail Possum (P. cinereus) · Painted Ringtail Possum (P. forbesi) · Herbert River Ringtail Possum (P. herbertensis) · Masked Ringtail Possum (P. larvatus) · Pygmy Ringtail Possum (P. mayeri) · Vogelkop Ringtail Possum (P. schlegeli) Pseudochirops D'Albertis' Ringtail Possum (P. albertisii) · Green Ringtail Possum (P. archeri) · Plush-coated Ringtail Possum (P. corinnae) · Reclusive Ringtail Possum (P. coronatus) · Coppery Ringtail Possum (P. cupreus) Acrobatidae Acrobates Feathertail Glider (A. pygmaeus) Distoechurus Feather-tailed Possum (D. pennatus)   Suborder Macropodiformes (cont. below) Macropodidae (includes Wallabies) Lagostrophus Banded Hare-wallaby (L. fasciatus) Dendrolagus (Tree-kangaroos) Grizzled Tree-kangaroo (D. inustus) · Lumholtz's Tree-kangaroo (D. lumholtzi) · Bennett's Tree-kangaroo (D. bennettianus) · Ursine Tree-kangaroo (D. ursinus) · Matschie's Tree-kangaroo (D. matschiei) · Doria's Tree-kangaroo (D. dorianus) · Goodfellow's Tree-kangaroo (D. goodfellowi) · Lowlands Tree-kangaroo (D. spadix) · Golden-mantled Tree-kangaroo (D. pulcherrimus) · Seri's Tree-kangaroo (D. stellarum) · Dingiso (D. mbaiso) · Tenkile (D. scottae) Dorcopsis Brown Dorcopsis (D. muelleri) · White-striped Dorcopsis (D. hageni) · Black Dorcopsis (D. atrata) · Gray Dorcopsis (D. luctuosa) Dorcopsulus Small Dorcopsis (D. vanheurni) · Macleay's Dorcopsis (D. macleayi) Lagorchestes Spectacled Hare-wallaby (L. conspicillatus) · Rufous Hare-wallaby (L. hirsutus) Macropus (includes Kangaroos and Wallaroos) Subgenus Notamacropus: Agile Wallaby (M. agilis) · Black-striped Wallaby (M. dorsalis) · Tammar Wallaby (M. eugenii) · Western Brush Wallaby (M. irma) · Parma Wallaby (M. parma) · Pretty-faced Wallaby (M. parryi) · Red-necked Wallaby (M. rufogriseus) Subgenus Osphranter: Antilopine Kangaroo (M. antilopinus) · Woodward's Wallaroo (M. bernadus) · Eastern Wallaroo (M. robustus) · Red Kangaroo (M. rufus) Subgenus Macropus: Western Grey Kangaroo (M. fuliginosus) · Eastern Grey Kangaroo (M. giganteus) Onychogalea (Nail-tail wallabies) Bridled Nail-tail Wallaby (O. fraenata) · Northern Nail-tail Wallaby (O. unguifera) Petrogale (Rock-wallabies) P. brachyotis species-group: Short-eared Rock-wallaby (P. brachyotis) · Monjon (P. burbidgei) · Nabarlek (P. concinna) P. xanthopus species-group: Proserpine Rock-wallaby (P. persephone) · Rothschild's Rock-wallaby (P. rothschildi) · Yellow-footed Rock-wallaby (P. xanthopus) P. lateralis/penicillata species-group: Allied Rock-wallaby (P. assimilis) · Cape York Rock-wallaby (P. coenensis) · Godman's Rock-wallaby (P. godmani) · Herbert's Rock-wallaby (P. herberti) · Unadorned Rock-wallaby (P. inornata) · Black-flanked Rock-wallaby (P. lateralis) · Mareeba Rock-wallaby (P. mareeba) · Brush-tailed Rock-wallaby (P. penicillata) · Purple-necked Rock-wallaby (P. purpureicollis) · Mt. Claro Rock-wallaby (P. sharmani) Setonix Quokka (S. brachyurus) Thylogale (Pademelons) Tasmanian Pademelon (T. billardierii) · Brown's Pademelon (T. browni) · Dusky Pademelon (T. brunii) · Calaby's Pademelon (T. calabyi) · Mountain Pademelon (T. lanatus) · Red-legged Pademelon (T. stigmatica) · Red-necked Pademelon (T. thetis) Wallabia Swamp Wallaby (W. bicolor)   Suborder Macropodiformes (cont. above) Potoroidae Aepyprymnus Rufous Rat-kangaroo (A. rufescens) Bettongia (Bettongs) Eastern Bettong (B. gaimardi) · Boodie (B. lesueur) · Woylie (B. penicillata) · Northern Bettong (B. tropica) Potorous (Potoroos) Long-footed Potoroo (P. longipes) · Long-nosed Potoroo (P. tridactylus) · Gilbert's Potoroo (. gilbertii) Hypsiprymnodontidae Hypsiprymnodon Musky Rat-kangaroo (H. moschatus)

This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)

Dansk (Danish)
n. - koala, pungbjørn

Nederlands (Dutch)
koala

Français (French)
n. - koala

Deutsch (German)
n. - Koala

Ελληνική (Greek)
n. - (ζωολ.) κοάλα

Italiano (Italian)
koala

Português (Portuguese)
n. - coala (m) (Zool.)

Русский (Russian)
коала, сумчатый медведь

Español (Spanish)
n. - koala

Svenska (Swedish)
n. - koala, pungbjörn

中文（简体）(Chinese (Simplified))
无尾熊

中文（繁體）(Chinese (Traditional))
n. - 無尾熊

한국어 (Korean)
n. - 코알라

日本語 (Japanese)
n. - コアラ

العربيه (Arabic)
‏(الاسم) حيوان استرالي من ذوات الكيس‏

עברית (Hebrew)
n. - ‮קואלה (חיית כיס אוסטרלית, דומה לדוב)‬

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