The bear that’s not….

… eucalyptus leaves are poisonous for most animals, our little koalas have a special organ for dealing with this fact. Its called a …

Koala in Tree showing claws
Koala in tree. Photo by freemake from Pixabay.

We like to refer to Koala Bears but the fact of the matter is as cute as these little guys are – they are not bears but marsupials. Marsupials meaning that they are born incompletely developed and are kept in the mothers pouch where they are fed milk while they complete their development.

Right, so we are talking Australia if its a marsupial, correct?

In this case, yes…

… BUT as a point of interest – there are marsupials in New Guinea, North America and South and Central America. The USA has 1, being the Virginia Oppossum (Didelphis virginiana). South and Central America fare a whole lot better with around 98 different ones.

So, getting back to our Koala’s …

Looking at their claws does give us a clue as to their lifestyle. Koalas sleep for up to 18 hours a day wedged in a tree. Having a reinforced cartilage cover over their spine base makes this feat a whole lot easier and more comfortable, not to mention, safer.

sleepy koala wedged in tree fork
Koala sleeping. Photo by sandid from Pixabay.

This habit is most likely due to their diet being a low nutritional one which also explains the need to eat up to 2 lbs (1 kg) a day. Another interesting twist on their food is that there are in the region of 700 different types of eucalypti trees with the koalas eating from only around 50 of them. Given that eucalyptus leaves are poisonous for most animals, our little koalas have a special organ for dealing with this fact. Its called a “caecum” and actually detoxifies the offending chemicals making the leaves safe to eat.

Koalas are known to need little water as they get so much moisture from the leaves (70% of the leaves are water) they eat which are often the younger and more nutritious leaves. This probably led to them being named as ‘koalas’ meaning ‘no water’ in the local aboriginal language. However, we now know that they do in fact drink water especially during heatwaves and droughts.

placid koala at top of tree
Koala feeding on youngest leaves. Photo by sandid from Pixabay.

Koalas are mostly placid creatures but the males will fight viciously over territories and even over specific trees. In addition, when somebody tries to pick up a koala it will defend itself using claws and teeth. they have sharp front teeth for nipping leaves off and the rear teeth are for chewing. these front teeth could inflict a nasty wound.

claws are long and sharp designed for climbing trees. their hands and feet are designed for gripping onto branches with the hands having two opposite thumbs enabling a good grip.

They have fur which is coarser than it looks and it repels rain, they have large ears and excellent hearing but very poor eyesight. Relying on smell to detect predators and rival koalas. On this score, koalas smell like eucalyptus due to all the leaves they eat. This along with being high up in trees help keep them out of predators reach. These predators include dingoes, eagles, pythons and large owls.

Koala dozing
koala, when eating just becomes too exhausting. Photo by Lars Thomsen from Pixabay.

Female koalas generally start breeding at 3 or 4 years of age with a gestation period of just 35 days, after which she gives birth to a single joey who remains in her pouch. A koala joey is less than an inch long( 2 cm) when its born. The birth involves the baby crawling unaided to the pouch and it finds a teat which swells to fill the mouth and so is difficult to be dislodged ensuring the baby has a constant supply of nourishment. The mother also tenses the muscle at the pouch opening, ensuring the little one does not fall out.

Our little koala will remain in the pouch for 6 to 7 months developing eyes and ears along with the rest of the body.

from 22 to 30 weeks the eyes have developed and the joey will peep out of the pouch getting its first introduction to the world using its limited vision and more powerful sense of smell. At this time the mother develops a substance which is termed ‘pap’ and on which the joey will feed, along with its milk. This helps with the transition from milk to leaves and also serves to pass on micro organisms from the mother to the young koala for digesting of leaves.

As our little friend develops it will ride on its mothers back and start to eat leaves but all this time has milk access, even when it no longer fits into the pouch, the teat elongates out of the pouch to provide the youngster the additional nourishment.

Our mother koala will continue breeding annually for the next 10 to 15 years.

koala and joey
koala mother and baby. Photo by Adri Marie from Pixabay.

Koalas appear sluggish in the trees as they are saving their energy and on the ground move at a very slow pace but are capable of ‘galloping’ at speeds of up to 18 mph (30 km/h) when threatened!

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