In brief: Traumatized elephants
A report in the British journal Nature provides vivid evidence that other animal species suffer from the psychological symptoms of traumatic stress that we like to think of as human disorders.
Elephants, like humans, are a highly intelligent, long-lived mammalian species with strong family ties, a complex social life, and long memories. They grow up in extended families headed mainly by grandmothers (older females). Human violence and habitat destruction have been breaking up those families for a century or more. It's estimated that in 1900, there were more than 10 million elephants in Africa; in 2005, after a century of ivory poaching, habitat loss, and legal culling, about a half million are left.