Relatively few animals have the ability to recognize their own reflection. The measurement for self-recognition is the mirror test, a psychological test developed by Gordon Gallup, Jr. Animals that can recognize themselves in a mirror include dolphins, orcas and elephants.
More on the mirror test:
- Human children generally cannot recognize their own reflection until they are about 18 months old.
- Some birds have passed the mirror test, including European magpies and trained pigeons, although it is not clear whether pigeons in general have the self-awareness to pass the test.
- Gorillas have had difficulty with the test, although Koko, a gorilla that uses sign language, has passed it. Researchers suspect that gorillas' problems with the test might be because gorillas consider direct eye contact a sign of aggression.