In theory, a reaction to an out-of-place mark in a reflection is assumed to be evidence of self-recognition for other animals as well. Chimpanzees, elephants, and dolphins are just some that have ...

Learn how cleaner wrasse used a mirror and even dropped food to test their reflections, a behavior linked mostly to mammals.

Cleaner wrasse have revealed a remarkable new side of fish intelligence. Marked with fake parasites, they used mirrors to inspect and remove the spots—far faster than seen in earlier tests. Even more ...

Researchers at Osaka Metropolitan University in Japan have discovered a previously undiscovered behavior in cleaner wrasse (Labroides dimidiatus). When presented with a mirror, the tiny fish not only ...