Growing to between 60-85cm in size, Koalas have grey-brown fur that appears soft to touch but is coarse like sheep’s wool. Even though they have poor vision, their large, round ears equip them with an excellent sense of hearing that helps detect predators and other Koalas. And their black, furless noses give them an acute sense of smell, helping them to identify other Koalas and their favourite food trees.
Having adapted to life in the tree-tops, Koalas have a cartilaginous pad at the base of their spine that allows them to sit between branches for extended periods of time. They also have five digits with strong claws on each of their front paws, two of which act like thumbs to help them grab a firm hold of branches. Two digits on their back paws are fused - perfect for grooming and scratching.
Adult males have a bald patch on their chest where a visible scent gland is located, which they rub against trees to mark their scent. Adult females are smaller than the males, have a thinner face and a relatively white chest with a pouch. Like their closest living relative, the wombat, these marsupial mammals have a backwards facing pouch and a hard bottom.
Jellybeans to Joeys, Adolescents to Adults
With a lifespan of about 10 to 12 years in the wild, Koalas are usually solitary animals; when they do come together, it is usually during the mating season (summer and spring) to fight, establish dominance and mate. Males make loud mating calls, ‘bellows’, that female koalas are thought to use to identify a new mate every year.
Males begin to mate at three to four years of age. Females reach sexual maturity at about two years of age, subsequently birthing one joey every year. On occasion, they may give birth to twins.
As marsupials, Koalas give birth to an underdeveloped, jellybean-sized joey that suckles in its mother's pouch for the first six months of life. Leaving the pouch, Koala joeys ride on their mothers back for the next six to twelve months. After becoming independent, adolescents will live close to the mother for the following twelve months, eventually leaving the home range during mating season to find their own territory.
A Home Among the Gum Trees
You probably already know that eucalyptus trees provide Koalas with a home and their main source of food, Eucalyptus leaves. An adult can eat almost a kilogram of leaves a day. But these leaves are difficult to digest, contain toxins and produce very little energy. So, Koalas sleep a whopping 19 to 20 hours per day to conserve what little calories their diet provides.
Yet, of the around 800 species of Eucalypt trees in Australia, only about 50 are a food source for these fussy eaters. For this reason, Koalas are only found only in the select parts of the country where these trees continue to grow: Queensland, New South Wales, Victoria and south-eastern South Australia.
Sadly, Koala fossils discovered in Western Australia and the Northern Territory suggest these cuddly marsupials once inhabited more forests across the country, before eventually being wiped out by land clearing for agriculture, industry and other forms of human occupation.
Habitat and Ecology
Koalas play an important role in the Australian ecosystem. Consuming a vast quantity of excess eucalypt vegetation, they help to reduce biomass that fuels intense and frequent fires during the dry season.
They also provide a source of food for Dingoes, Wedge tailed Eagles, large owls and even Goannas; their droppings act as a fertiliser for the forest floor and provide food for insects and small rodents; and their warm, insulating fur is stolen by birds, like the Brown-headed Honeyeater, and used for building nests.
Vulnerable to Extinction
You might be surprised to hear that the koala is now listed as an endangered species; the IUCN updated their conservation status in February of 2022, with populations facing extinction in both New South Wales and Queensland. Across Australia, their numbers have decreased by fifty percent in just the last two decades.
Habitat loss from fires and logging is fast contributing to their decline. Unable to seek refuge in trees, Koalas are more likely to be on the ground; increasing the likelihood that they will be attacked by domesticated dogs, hit by vehicles or vulnerable to their natural predators.
Preventing further habitat loss is one of the most effective ways to ensure this iconic animal does not become extinct. Yet the Koala’s plight has only worsened, now that plans are in place to log Australia’s native forests, burn them for electricity and sell that as ‘renewable energy’.
It's not all bad news. Wilderness Australia is campaigning to prevent this irresponsible industry from taking hold, protect the native forests Koalas depend on and preserve Australia’s precious biodiversity. Click here to join our community and keep updated about our important work.
By Zoe Martin