(Phascolarctos cinereus) These marsupials are one of the most popular Aussie creatures with both locals and tourists alike. Koala is an aboriginal term which translates as ‘non drinker’ while the scientific name means ‘ash grey pouched bear,’ although they are not bears at all. Along with the Greater Glider (topic of blog #3) the Koala survives on a diet of gum leaves. They are very fussy eaters with strong preferences for about ten species from an available 600-700 different gum trees.
An adult consumes around 500gr of leaves per day. Gum leaves are low in nutrition and to most animals they are extremely poisonous but the slow metabolism allows Koalas to keep food within their system until maximum nutrition is extracted. This slow metabolic rate is also the reason they sleep 18hrs a day and conserve maximum energy. Females start breeding from three years of age, breed once a year and give birth 35 days or so, later.
Like the Kangaroo, a tiny, unfurred and blind joey finds its way into mum’s pouch on its own. For the first six months, the joey lives on an exclusive diet of milk. It leaves the pouch for short periods and remains on mum’s chest / in her arms.
Mums and joeys communicate via soft clicking, murmuring and squeaking sounds. Grunts signal a reprimand. Adult males bellow to show dominance and all Koalas can sound like a screaming baby when in distress. Shaking/trembling generally accompany this sound.
It continues to drink milk for the first year although it is too big to fit in the pouch. Pap is produced by the mother as a means of transitioning from milk to leaves – basically she produces this soft, runny substance as a means of passing on micro organisms from her own digestive tract. Joey is often seen on her back now.
The Koala’s nose is one of its most important features, and it has a very highly developed sense of smell. This is necessary to differentiate between types of gum leaves and to detect whether the leaves are poisonous or not.
Adult sizes: 70-90cm (27-36 inches) Weight: 4-9kg (9-20lb) Southern Koalas are 30% larger than Northern and Males generally larger than females. Lifespan 10 – 17yrs
Threats: Early settlers hunted them for their plush, warm pelts to the point they were extinct in South Australia by 1924. Now almost 80% of Australia’s Eucalypt forests have been decimated and the rest is unprotected or on private land, for the most part. 4,000 Koalas are killed by cars or dogs each year. Large scale Wildfires /Bushfires are common in summer months and also take a toll. Finally, what we are seeing locally is ‘dieback’ which results from land degradation, leaching of soil nutrients, changes in the composition of vegetation communities, rising water levels underground, salination of the soil, erosion caused by wind and water, exposure to weather and excessive defoliation. The last cause refers to a loss of leaves to the point the tree cannot photosynthezise (feed itself) and dies.
This is a photo taken at Raymond Island (Victoria) during the recent Koala count which showed a good result. This is a site which suffered overcrowding by Koalas and many had to be relocated/sterilised to give the vegetation a chance of survival. The older trees are not likely to recover but thousands of seedlings are being planted for future use.
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Until next month, take care and be well.