Home Learn about Koalas The sharp bits
The sharp bits

The sharp bits

 

It's very important to remember that while these animals look cute and placid, they can lash out with their very sharp claws very quickly and also inflict deep bites on anyone or anything that it feels threatened by. Even a very sick koala should not be touched by anyone unfamiliar with them.

 

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The hand has 2 “thumbs” that oppose three fingers and are responsible for the koala's powerful grip.

The big toe on the foot (hind paw) sticks out at right angles to the foot and acts like a thumb,  and has no claw.

The next 2 toes are joined at the base and are used like a comb for grooming. A healthy koala has a beautifully groomed coat.

 

          koala bullet Did you know koalas have finger prints?

          Koalas are one of the few mammals apart from primates to have fingerprints. Koala fingerprints so closely

          resemble human fingerprints that it can be hard to distinguish between the two.

 

                                           finger print                                       http://naturalscience.com/ns/articles/01-04/ns_hll.html        

                                        

Koalas are often thought of as clumsy and sluggish animals, and while they move at a slower pace most of the time, their long limbs can propel them rapidly over the ground or up a tree trunk when needed. Koalas walk like most 4 legged animals - diagonally opposing limbs alternately.

When climbing, koalas grip the trunk of a tree with their sharp claws and with both arms pull upward and pushing with their legs. A koala cannot come down a tree head first like possums. They climb down the in small jumps bottom first.

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 “In the case of the koala, which has become perfectly adapted to its environment, its digestive apparatus, both structurally and functionally, has been developed to assimilate the special diet of eucalyptus. The koala at the same time, wholly dependent upon a small variety of eucalyptus trees, and may therefore be regarded as the slave of its environment”

 Ambrose Pratt 1936 - The call of the koala.

 

 


 

 

 

How can an animal grow to a size of up to 14kg by eating eucalyptus leaves?

 

These leaves contain oils that are toxic to most herbivores.

 

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Composition of a typical eucalypt leaf

 

55% water

 

15% fibre

 

13% tannins and other phenolics

 

 7% starch and sugars

 

  6% lipid (including essential oils)

 

4% protein

 

They chew the each leave meticulously into diamond shaped pieces that pass into the stomach and small intestine, where nutrients are digested and absorbed. The coarser bits of leaf then pass into the caecum where they remain for up to eight days where bacteria “ferment” the plant cells and the koala absorbs extra nutrients.

 

The size of a koala's caecum is what sets it apart from other animals, it has a complicated digestive system and is the key to how the koala can survive on such a nutritionally poor diet.

 

 

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     Eucalypt leaves are so high in lignified fibre, that a koalas stomach is

     filled quickly limiting the amount they can eat at one go.

 

 

 

young teeth                                       aged teeth

 

 

 

 

 

 

 

Depending on its size a koala needs to eat about up to 1kg of leaves a day - that's about 2 shopping bags full. That's a lot of chewing! They have very powerful jaws and muscles so they can chew and grind the leaves very fine before they swallow.

 

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                        As a koala gets older its teeth wear down from the constant grinding of leaves.            koala bullet                   

                       The more worn the teeth, the bigger the leaf pieces and harder to digest and get the most absorption of nutrients.

 

                        Fewer nutrients lead to malnutrition. Aged koalas can't eat enough leaves to sustain good body condition.      

 

 

 

Most people don't realise how choosey koalas are with their choice of leaves they will eat. A koala that has come into care at a wildlife shelter can reject many branches of leaves that are offered to them, before they find one that they will eat. Often this can be from the same tree.