You hear, anecdotally, that an elephant never forgets, and I do believe this is true. Up in Kenya, at Amboseli, researchers have done playbacks of long-distance contact calls in an experiment that suggests adult female elephants can recognize more than a hundred individuals. When the calls were from a herd with which they had associated, the elephants being tested responded with their own contact calls. When the vocalizations were from an unfamiliar herd, they bunched and backed away.
