Koala
'Koala' is an Aboriginal word meaning 'no drink'. They get 90% of their water from gum leaves. The Blue & Manna gums are their favourite!
There is just ONE species of koala, the nocturnal, sleepy herbivore which inhabits the east coast woodlands from southern Queensland, New South Wales, Victoria and South Australia. The Northern Territory and Western Australia have no remaining koala population, and there are no (wild) koalas in Tasmania.
Koalas are one of the few mammals that live on gum leaves. There are over 900 species of gum in Australia, but koalas are fussy - only consuming the leaves of few gumtrees. The Blue & Manna gums are their favourite!
Koalas have a highly developed sense of smell which they use to detect if the leaves can be safely eaten. If even their favourite trees are growing in poor soil, the leaves may be too dangerously toxic. Remarkably, a koalas liver de-toxifies the phenolic and terpene compounds in the gum leaves,which would poison almost any other animal.
Koalas are well suited to life in trees. They have an excellent sense of balance and strong limbs and thighs. Fur on the koala’s bottom is densely packed to provide a cushion. Their paws have rough palms and soles and they have 5 digits. 2 is opposite 3, acting like a human thumb to provide a firm grip.
To survive on a very low nutrient food source, koala joeys survive on their mother’s faeces (pap). It contains digestive aids to make it possible for the koala to survive on it. Koalas' slow metabolic rate (similar to a sloth), reduced brain size and sleeping 19 hours a day all conserve precious energy to make it possible to exist on such a diet.
Koalas can live up to 20 years and weigh over 9kg (20lbs). They produce 1 joey a year for up to 13 years. The joey lives in the pouch for the first 6 months before the weaning process begins. After one year they leave their mother and are mainly solitary, moving about on all fours between trees, in a well-defined range. Summer is the mating season and it is at this time that the males call be heard giving out deep bellowing sounds.
threat
Traditional enemies for the koala included the dingo & Aboriginal People. Today their biggest problem is lack of habitat.
The arrival of Europeans over 200 years ago led to a loss of over 80% of Eucalyptus (gum) Forests, due to land being cleared for grazing. In only 5 years from 1939 to 1924, over 8 million koalas were killed for their fur in Victoria alone. Today it is estimated only a few hundred thousand remain.
For their survival, koalas were introduced to offshore islands, like Kangaroo Island. From 4 individual koalas, now, an estimated 30,000 live. With a depleted gene pool from just a few adults, island populations like those on Kangaroo Island have not controlled themselves like their mainland cousins. The isolation from predators has meant that overpopulation is their biggest threat. Over grazing has meant that island koalas are on the verge of starving themselves to death.
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To keep their numbers in check on the islands the government proposed culling, but this sent alarm bells ringing in the tourism and conservation sectors. At present, a sterilisation program is underway to reduce populations to a controllable level. Moving them to the mainland has been considered but there are few areas of native Eucalyptus Forests that can support a growing koala population. Very few eucalyptus forests are protected and most are in private hands.
On the mainland, Chlamydia affects koala populations in times of stress. How do koalas get stressed? Loss of habitat / lack of food and resources. Chlamydia has no affect on populations with unlimited resources but can cause death or sterility when food sources are low. Genetically stronger animals survive to continue breeding.
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A campaign called 'No Tree, No Me' has been instigated by wildlife warriors and conservation societies to create large mainland habitats. While the planting of more trees is the obvious answer to boost population levels, critics say that despite chlamydia, lack of modern-day predators means that koalas will eventually eat themselves out of house and home, no matter where they go.