Koalas: Not the smartest tool in the shed

Sure, they’re cute and cuddly. They’re incredibly photogenic and they’re unashamedly Australian. However, Koalas seemingly aren’t very good at being animals.

Silly Koala. Source: Free Great Picture

What do I mean by this? Well, koalas seem to have an uncanny ability to defy nature. They lack higher-level recognition, don’t have a lot of contingencies and strategies for continued survival, and eat things that by rights shouldn’t be eaten.


Koalas have a ‘smooth’ brain.  This means that they lack higher level recognition and understanding that many other animals have.

If you gather a bunch of Eucalyptus leaves, which the koalas eat, and put them on a plate in front of the koala, the koala won’t know what to do with them; they just sit there and gawk at it.

They lack the ability to discern that it’s still food given that the leaves have moved off the tree and onto a new source that they’re unfamiliar with.

Another fun biproduct of their smooth brain is that koalas don’t really seem to understand what rain is. They will just sit in that rain wondering why they get wet until the rain passes.

Happy koala after the rain. Source: Free Great Picture



As the Koala’s diet consists entirely of vegetation, read leaves, they end up consistently grinding down their teeth on the hard chewing surfaces. This is especially challenging for the koala, as the Eucalyptus is a tough leaf and is difficult to chew and digest.

Other marsupials have adapted strategies to combat this. The wombat has rootless teeth, which means that their teeth never stop growing, so they can continue eating. Kangaroos have sets of teeth that rotate towards the front of the mouth as the older teeth grind down.

Koalas, however, haven’t adapted at all to grinding down their teeth. As such, once their teeth have ground down, they cannot eat their main source of food anymore and simply starve to death.


The koala’s diet consists mainly of Eucalyptus leaves. Koalas are only one of three animal species to be able to survive on such a diet, and with good reason.

The Eucalyptus leaves are low in nutrition and calories and are very fibrous, meaning they require a lot of chewing before they can be swallowed.

On top of this, the leaves are extremely poisonous. The koala has a large caecum, which allows it to digest such a poisonous food. That doesn’t stop the fact that the Eucalyptus leaf lacks goodness and nutrition, meaning that koalas get very little energy from the effort they put into eating.

As their food doesn’t provide a lot of energy, koalas are rather lethargic creatures. They’re never able to be in a hurry to arrive anywhere, and end up sleeping over 20 hours a day. In that sense at least, I feel like the koalas have it made.

11 Responses to “Koalas: Not the smartest tool in the shed”

  1. Chris says:

    Hi Jasmin, They are definitely still adorable! Fortunately, or unfortunately depending on how you look at it, koalas don’t get high on eucalyptus leaves. The misconception probably arose as a potential explanation for them sleeping for their 22 hours a day. However, it has since been related to the lack of energy they get from the leaves, rather than getting stoned from them. Or maybe they’re stupid in their cleverness? Thanks!

  2. Chris says:

    Funnily enough I was originally going to write about pandas! Then I did some research and realised koalas are also quite dopey. I’m tempted to talk about pandas too!

  3. Chris says:

    Hi Sarah, it is quite sad. Koalas average life span is between 13-18 years, and if they aren’t eaten by predators or die by other causes, this is around the time when their teeth grind down and they’re no longer able to chew their food. I think it’s so ingrained in their brains to eat eucalyptus leaves that they don’t think to try other forms of food. They also probably don’t have enough energy to forage for food that they don’t need their teeth to consume.

  4. Jasmin says:

    I love koalas. I think they are the perfect representation of Australia. I think their dopey-ness only makes them more endearing.

    Is there any truth to the whole “koalas get stoned off of eucalyptus leaves” myth?

    Even though koalas are dumb dumbs they still managed to survive somehow! Maybe they are clever in their stupidity? Great read!

  5. Sarah Misev says:

    Very interesting post, thank you! I had no idea about the koala’s lifestyle, only that they are so adorable. I am saddened to hear that they starve to death once they have no more teeth. Is there a common age that they all reach when this starts to happen? Surely they could eat something else when they are in starvation mode? Or are they just addicted to eucalyptus oil?

  6. Yang says:

    This is really an interesting topic! This has a bit surprised me that koala is not smart as I think.
    I noticed that koalas sitting and sleeping in heavy rains, and I thought they were too lazy to move, so instead, they just stay there to enjoy a natural bath haha… That’s interesting to know they even can’t understand what rain is.

  7. jordii says:

    I had no idea koalas were so behind. Or that their brains are smooth! Thanks for writing this post!

  8. cstevens1 says:

    Hi Natalia, you’re probably safe with the oil. As with anything, eucalyptus is poisonous if you take too much. It’s just that you don’t need to take a lot of eucalyptus for it to do a lot of damage. Taking 3.5 mL of pure eucalyptus oil can be fatal. For comparison, koalas eat 200-500 grams of eucalyptus leaves per day! The good news is that eucalyptus oil is well regulated in Australia and the oil you take for stomach aches probably contains mostly water and other ingredients so it’s safe to take. For more information check out http://www.eucalyptusoil.com/safety.

  9. Ehlana Tompsett says:

    Oh my goodness. Are koalas by some chance distant relatives of pandas? They’re the only other species I know that’s driving themselves to extinction through their own lethargy.

  10. Natalia Radjah says:

    Wow! it’s really shocking me out when I read that eucalyptus leaves are extremely poisonous. I usually use eucalyptus oil to relieve stomachache and never any problem with that. That’s quite confusing for me.

  11. Funny read. Didn’t know Koalas have evolved so poorly over the years. Surely you would think they have developed some kind of evolutionary advantage after eating leaves for so long.

    I think they parallel pandas in a certain way – being exceptionally poor at reproducing themselves.