) is a thickset arboreal
marsupial herbivore native to Australia, and the only extant representative of
the family Phascolarctidae.
The Koala is found all along the eastern coast of Australia from near
Adelaide to the southern part of Cape York Peninsula, and as far into the
hinterland as there is enough rainfall to support suitable forests. 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.
The word "koala" comes from the Dharuk word gula.
 Closely related words appear in
other Australian Aboriginal languages, including:
- In the Blue Mountains of New South Wales, Aborigines called Koalas by the
- Near Sydney, Aborigines called Koalas by the word Koolahs.
- In the Murray Region, Aborigines called Koalas by the word Karbors.
- Other Aboriginal names for Koalas include: Bangaroos, Koolewongs, Narnagoons
and Colos. .
It is commonly said that the common name 'Koala' is an Aboriginal word
meaning "no drink." The Koala actually does drink water, but only rarely, due
to its diet consisting of eucalyptus leaves, which contain sufficient water to
obviate the need for the Koala to climb down for a drink.
Early European settlers to Australia called the Koala the Native Bear
and the Koala is still sometimes called the Koala Bear, although it is
not even a placental mammal (like bears and most other mammals) - it is a
marsupial. The Koala's scientific name comes from the Greek: phaskolos
meaning "pouch" and; arktos meaning "bear". The cinereus epithet
is Latin and means "ash-coloured".
Taxonomy and evolution
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 weights are 12 kg for males and 8.5 kg for females.
In tropical and
sub-tropical Queensland, however, the Koala is smaller (at around 6.5 kg for an
average male and just over 5 kg 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. The
variation from one form to another is continuous, and there are substantial
differences between individual Koalas in any given region such as hair color.
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 eucalyptus forests grew in the place of rainforests.
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. Its origins are unclear; however, since its pouch opens
backwards instead of forwards like most other marsupials, it is theorised that
it may have evolved from a burrowing marsupial.
The Koala is broadly similar in appearance to the wombat (its closest living
relative), but has a thicker, softer coat, much larger ears, and longer limbs,
which are equipped with large, sharp claws to assist with climbing. Weight
varies from about 14 kg for a large, southern male, to about 5 kg for a small
northern female. Contrary to popular belief, their fur is thick, not soft and
cuddly. Koalas' five fingers per paw are arranged with the first two as
opposable thumbs, providing better gripping ability.
The Koala has an unusually small brain, with about 40% of the cranial cavity
being filled with fluid, while the brain itself is 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
It is a generally silent animal, but males have a very loud advertising call
that can be heard from almost a kilometre away during the breeding season. There
is little reliable information about the lifespan of the Koala, but in captivity
they have been observed to reach the age of 15 years.
Females reach sexual maturity at 2 to 3 years of age, males at 3 to 4 years.
If healthy, a female Koala can produce one young each year for about 12 years.
Gestation is 35 days; twins are very rare. 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 the size of a jelly bean, 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. The
downward-facing pouch provides a much shorter trip from the birth canal to the
pouch than in other marsupials. Thus, the forearms need not be as developed for
the journey into the pouch, and can develop more fully for excellent climbing
ability later in life.
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 30 weeks it has begun to
eat the semi-liquid form of the motherís excrement called "pap". The baby Koala
will remain with the mother for another six months or so, riding on her back,
and feeding on both milk and gum 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.
Koala road sign
warning not to run them over
Ecology and Behavior
The Koala lives almost entirely on eucalyptus leaves. This is likely to be an
evolutionary adaptation that takes advantage of an otherwise unfilled ecological
niche, since eucalyptus 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 (which conserves energy) and rests motionless for about 19 hours a day,
sleeping most of that time. Koalas spend about 3 of their 5 active hours eating.
It feeds at any time of day, but usually at night.
An average Koala eats 500
grams of eucalyptus leaves each day, chewing them in its 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: when young are being weaned, the mother
passes unusually soft faeces, called pap, which is rich in these bacteria, thus
passing these essential digestive aids onto her offspring.
The Koala will eat the leaves of a wide range of eucalypts, and occasionally
even some exotic species, but it has firm preferences for particular varieties.
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 exist
in surprisingly arid areas.
Many factors determine which of the 800 species of
eucalyptus 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
The Koala was hunted almost to extinction in the early 20th century, largely
for its fur. 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 ever-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 Australian Koala Foundation has mapped 40,000 km≤
of land for Koala habitat and claims it has strong evidence to suggest wild
Koala populations are in serious decline throughout the species' natural range.
Although the species covers a massive area, only 'pieces' of Koala habitat
remain. These pieces need to be managed, protected and restored in a coordinated
way. Presently, many are being lost to weeds, cleared for agriculture, or carved
up by developers. Other threats come from logging, poor management, attacks from
feral and domestic animals, disease and roads.
In contrast to the situation on much of the mainland, where populations are
declining, the Koalas of many island and isolated populations have reached what
some have described as "plague" proportions. 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, with ecologists suggesting that the Island can sustain
10,000 at most.
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,
sterilisation and translocation programmes 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 sterilisation
method, wherein the animal must first be captured, are hormonal implants that
can be injected via darts.
The Koala occurs in four Australian states. Under state legislation, the
species is listed as Vulnerable in the South East Queensland Bioregion,
Vulnerable in New South Wales and Rare in South Australia. The species' national
status is under review. The IUCN lists the species as Near Threatened.
In popular Western culture, the animal is usually either depicted as a cuddly
innocent, or as a curmudgeonly character never terribly impressed by the things
he sees around him.
Qantas airlines used a Koala who continually complains about the airline's
reliability in a series of television commercials.
Rugby union team Queensland Reds has the Koala as its logo.
An Australian children's show has animated characters headed by The Koala
Eminent cartoonist Patrick Cook has periodically depicted the koala as a
wine-swilling creature of homicidal, rather than merely curmudgeonly,
Blinky Bill is the koala star of several books, TV shows, a movie and games.
Koala Lumpur: Journey to the Edge is a PC game with a koala as the main
Koalas as pets
In spite of their looks, people generally do not have Koalas as pets. This is
because they are unsuited to a suburban environment, and as it is illegal to do
so in Australia. 
The Koala is one of the few mammals (other than primates) that has
fingerprints. In fact, koala fingerprints are remarkably similar to human
fingerprints; even with an electron microscope, it can be quite difficult to
distinguish between the two. This is an example of coincidental evolution.
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are koalas mean like the tv says?
(reply: As with all animals,
especially those that look cute and cuddly, you must be very careful that they
don't attack you. Koala bears we understand can be quite nasty at times)
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Hi - I love Koalas and I even work at Lone Pine Koala Sanctuary. I'm a Bin Run/
cleaner boy. The koala there are just all cute. Thanks Todd
i love koalas 2 but what are some adaptations ?
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Koalas' never drink because they get their drink from the
leaves they eat
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Q. what r some adaptations of a koala bear ...?...? any 1
It was O.K but I was wondering why they never drink ??
Is it because they find enough moisture in the
food they eat and they move very little, sleeping most of the time, therefore
they do not need so much to drink in the first place ?
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Q. Koalas r gr8!!! but they not called koalas what are they
called?? any1 know plz say!
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