A Tiny Reef Fish Can Recognize Itself in a Mirror

And because fish lack limbs or an elephantine trunk, it would be hard to interpret potential mark-removal behaviors anyway—suggesting the test itself might be biased toward animals that more closely resemble humans. So Jordan and his team turned to 10 wild-caught cleaner wrasse, a type of fish known to care quite a bit about unusual spots on others; it gets its name from eating parasites and dead tissue from larger fishes’ skin. And based on their behaviors alone, the fish indeed seem to have passed the mirror test.

Source: www.scientificamerican.com