What do you think of this fact?
Fingerprints feel like the most human thing about you. Police, your phone, border control: they all rely on the ridges on your fingertips being one of a kind. So it’s pretty strange that a sleepy, tree-climbing marsupial from Australia has nearly the same ones.
Discovered at a wildlife park
In the mid-1990s, Maciej Henneberg, an anthropologist and forensic scientist at the University of Adelaide, examined koala paws at a wildlife park near Adelaide. What he found surprised him: koalas have real fingerprints with loops, whorls and arches, the same basic patterns crime-scene experts use to tell humans apart.
The resemblance is huge. According to Wikipedia, even with an electron microscope it can be quite difficult to tell a koala’s prints from a human’s.
Same solution, totally different family
Here’s the twist: koalas aren’t closely related to us. Our last common ancestor lived more than 100 million years ago, according to PBS NOVA. Plenty of primates, like chimps and gorillas, have fingerprints. Outside the primates, though, these ridges are rare. According to Wikipedia, one of the few other examples is the North American fisher.
Scientists call this convergent evolution: two species independently arrive at the same solution because they face similar challenges. Henneberg suspects the ridges help koalas eat. They have to hang on to eucalyptus branches while picking out and checking individual leaves. The ridges improve both grip and sense of touch.
Koalas at the crime scene?
Back then, Henneberg noted that while it was extremely unlikely koala prints would turn up at a crime scene, police should at least be aware of the possibility. The internet turned that into a myth about detectives regularly mixing up koalas and suspects.
There’s no documented case of it. An Australian police officer told the fact-checking site Snopes he had never heard of such a mix-up.
In the end, it’s almost comforting: your fingerprint really is unique. It’s just not quite as exclusive as you thought.