A finger-length fish has reignited a long-running debate about self-awareness, cognition and how much we’ve underestimated ...

It’s almost automatic—if you notice a smudge when you look in the mirror, you wipe it off. Seems simple, but only a few particularly clever species such as orangutans and dolphins share this ability ...

Before deciding whether or not to fight another fish, cleaner wrasse check their own reflection in a mirror and size themselves up. First, Taiga Kobayashi at Osaka Metropolitan University in Japan and ...