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The mirror test is a measure of self-awareness developed by Gordon Gallup Jr. in 1970.
Animals that have passed the mirror test are all of the great apes (humans, bonobos, chimpanzees, orangutans and gorillas), bottlenose dolphins, killer whales, elephants, and European Magpies. Initially, it was thought that gorillas do not pass the test, but there are now several well-documented reports (such as one gorilla, Koko) of gorillas passing the test. In 1981, Epstein, Lanza and Skinner published a paper in the journal Science in which they argued that the pigeon also passes the mirror test.Humans tend to fail this test until they are about 18 months old, or the "mirror stage".Dogs, cats and 1 year old children, for example, usually react to a mirror in fear or curiosity, or simply ignore it, while birds often attack their own reflections