Long‐term retention of self‐recognition by chimpanzees

Two young chimpanzees showed retention of self‐recognition after 1 year without access to mirrors. A year earlier the animals were positive on the Gallup dye test. One year later they were once again anesthetized, marked on the brow and ears, and following recovery, exposed individually to a large mirror. Both demonstrated mirror‐orientated mark‐directed responses. Time‐sample observations of behavior toward the mirror further support self‐recognition. The chimpanzee's self‐awareness, as inferred from its self‐recognition, appears to be a stable characteristic of the animal.