Savannah: These fish know their own faces.

Cleaner fish (Labroides dimidiatus) can pass one of the trickiest intelligence tests out there: the mirror test. The mirror test is simple. Put a mark on the subject, then show them a mirror. If the animal tries to remove the spot, that tells us they know the reflection in the mirror is them, not another animal. Only a handful of non-human animals have passed, including orcas, chimps, and magpies. And most human children don't pass it until age two. Not only that, but these cleaner fish recognize themselves in photos, too.

So, why would they need to be so good at telling fishy faces apart? Well, cleaner fish are territorial, and they'll attack invaders. Researchers showed them pictures of themselves, unfamiliar fish, and photoshopped images of their own face on strangers' bodies, and vice versa. They attacked the image of the stranger fish and their body with a strange face, but never their own face, regardless of the body. Which tells us that -

[end]