A Koala Did it, I Swear!

Did you know that koala fingerprints are just as unique as human fingerprints and have been known to be confused with human fingerprints in a crime scene? That's right - if you're going to do something illegal, maybe do it in Australia with a koala. Yes, you read that correctly and no, we did not make that up.

Before we dive too far into the "how" let's talk about the "what" and "why" as in "what are fingerprints?" and "why do we need them?" Fingerprints are friction ridges found on the pads of the phalanges of some species of animals. Primarily observed in mammals, fingerprints serve two purposes in the wild: grip and increased touch sensitivity. In physics you learned that friction is the force that resists motion and prevents two surfaces from sliding against each other, so the more ridges, the more friction, and thus the better the grip. It makes sense that most species of primate have fingerprints as they are avid climbers who have the ability to hang, use tools, and even have the ability to make tools.

People have expanded the use of fingerprints to include identification; we even have databases such as the Automated Fingerprint Identification System (AFIS). The FBI uses IAFIS (I for "integrated") for the identification and matching of known and unknown fingerprints. Fingerprints are now used for identification other than for those related to crimes: now you can use a live scan of your fingerprint to unlock some of your personal devices such as your phone or laptop.

What does that have to do with koalas? Well, hopefully you are not illegally housing one and giving it a cellphone. Koalas don't need fingerprints for electronics, but for grip. Koalas are an odd species of marsupial (not bears) that eat roughly 50 species of eucalyptus (there are about 700 total, so that's less than 10%). Eucalyptus leaves are not from shrubs, but from large trees, so of course, the koala has to have incredible grip to be able to get the food it desires. Remember, more ridges mean more friction, and more friction means better grip. Having a good grip for a koala means not falling hundreds of feet to its death in an attempt to get food.

So, given that koalas have human-esque fingerprints, have koala prints been found at a crime scene yet? In the United States? No. The U.S. does not have wild koalas, nor does it have abundant forests of the 50 species of eucalyptus the koala will eat. Potentially, there could be a crime that we missed in our research, but it would have to have been related to a zoo escape, as koalas are native to Australia. From what we were able to find, there are no records of koalas committing a crime and the fingerprints coming back as koala and not human, but that does not mean that it has not happened. The fingerprints left behind by a koala are incredibly difficult to discern from a human's to the point that a specialist would be needed to make that identification.