The Koala: A Creature for Our Time

Adapted from a talk intended for the edification of older students in a secondary school

The koala is an arboreal mammal native to Australia, one of that island nation’s most iconic fauna.  Though commonly called a ‘koala bear,’ it is not closely related to ursines, nor indeed is it even a placental mammal, but rather a marsupial like the kangaroo, giving live birth to an almost larval offspring which then nurses in a pouch until maturity.  Koalas are medium sized animals, averaging about three feet in length and weighing about thirty pounds or so, with some sexual dimorphism.  They are also retarded.

[Image found through Google]

As a disclaimer, I use that term in its purely clinical sense, and in no way do I mean to imply anything pejorative about this animal or any person.  I mean only that the koala as a species displays categorically the characteristics of developmental problems related to its cognitive function.  All koalas have tiny brains relative to their body mass; in fact, they have the second-lowest brain-size-to-body-size ratio of any vertebrate (the lowest is the –I’m not making this up- bony-eared assfish).  Their brains are not only tiny, but smooth.  Think of a walnut, but without the wrinkles.  The rest of its skull is full of cerebrospinal fluid, much like an unfortunate born with hydrocephaly.  Rather than being a birth defect, however, this is the norm for the species.

No other marsupial shares this characteristic to this degree, and scientists believe that the ancestors of the koala, including the marsupial megafaunus giant koala (which was the same size as the regular koala – try harder scientists) had brains that filled their skulls in a normal way.  The reasons for the koalas’ seemingly dysgenic condition have to do with their environment.  As Australia changed over the millennia, the sorts of forests the forebears of the koala lived in changed or died out, and selection pressures forced the species to a fork in the road.  They could move to where the nutritious plants were and fight for a spot in the food chain, or they could live in the middle of nowhere and eat crap.  You may be able to guess what happened.

Koalas live almost exclusively on the leaves of the trees of the genus eucalyptus, which are both highly toxic and have almost no nutritional value.  This is enough to keep almost every other animal in Australia from trying to eat them, which in turn means there is no real competition for them.  For the koala, this made for an opportunity.  They could have all the food they wanted, so long as they were willing to accept some evolutionary trade-offs, like the aforementioned ubiquitous retardation.  Over time, they adapted to this lifestyle such that it became their norm, and continues to be so to this day.

One might well wonder how they could live in such a way without being wiped out by predators.  Koalas are so unable to adjust mentally that, as is often noted, they will starve to death rather than eat fresh eucalyptus leaves from a plate, seemingly reasoning that they cannot be real since they didn’t pluck them from a branch.  Koalas sleep about twenty hours a day, move extremely slowly, use what little caloric energy they consume to continually vomit up and re-digest their eucalyptus leaves, then eat more leaves and sleep again.  They live alone and do not like the presence of other koalas, being wholly incapable of cooperation.  Surely they should have met the fate of the dodo by now? 

However, by living as they do, in areas devoid of anything worth eating by normal animals, there simply aren’t any great numbers of predators out to get them.  There is the occasional dingo (more on them in a moment) or eagle that can grab a young one, but for the most part, koalas are under no threat from the natural world.  Their main causes of death are falling out of trees, mitigated somewhat by the fluid cushioning nature has given their peach-pit brains, STDs (really), getting hit by cars, and the inevitable starvation that occurs after about a decade of life, when their teeth wear down from eating the toxic roughage that makes up their diet.  They eke out a dull and meager existence in a wasteland devoid of stimulation, challenge, or mental growth, but as it is all they know and all they can conceive of, they endure as they do, unaware that their ancestors were much different creatures.

By way of contrast, consider the dingo.  The dingo is a kind of dog, but beyond that, little can be said of them for certain.  It is a matter of debate whether they are a distinct species from the domestic dog, canis lupus familiaris, or a variant of the same.  Certainly they can and do breed with domestic dogs, but then, dogs can interbreed with wolves and coyotes as well.  Likewise, it is an open question whether the dingo is truly wild or merely feral.  The native people of Australia adopted the dingoes into their societies, but they live just fine alone in the bush. 

Interestingly, no one is even sure how the dingoes got to Australia in the first place.  Unlike the koala, they are an introduced species, but when this happened is unknown.  The Aboriginals walked and boated there around 50,000 years ago, but then the sea levels rose and contact with the outside world was virtually non-existent.  Genetic evidence shows the dingos to be related to dogs from New Guinea, but archeology indicates they must have gotten to Australia much later that the humans did, so unless they swam a good way or were brought by some unknown pioneering mariners from anywhere from Melanesia to south India, their origin story is anyone’s guess.

Dingoes, like the koalas, had to adapt to changing conditions, but unlike the latter, the former learned to exploit the full range of what the new world they found themselves in had to offer.  Dingoes eat everything and anything- kangaroos, wombats, the occasional koala, cattle, fish, human garbage, and, sadly and infamously, small humans.  Even when the government of Australia treated them as pests in the land their ancestors settled and sought to fence them off and exterminate them in favor of new and more profitable introduced species, it was to no avail.  Dingoes are creative, resourceful, adaptable, and above all clever creatures, and as much as can be said for an animal, they seem almost gleeful when overcoming challenges. 

What lessons can nature teach us from the example of these two species?  One can live as the koala, sinking to the level of one’s surroundings, vegetating in waking sleep and consuming the equivalent of cardboard doused in pesticide until an early and unhealthy death, or one can find solace in the struggle, becoming a versatile carnivore that can never be wholly tamed, a threat that no government can really deal with, since what barrier can threaten those for whom the challenge is the point?  The choice is yours.