"I find myself believing strongly that,on this planet, consciousness is not restricted to human beings. In one of the most deeply moving of David Attenborough's television programmes (Echo of the elephants, BBC, January 1993) was an episode that leaves us hard pressed not to believe that elephants, for example, not only have strong feelings but that these feelings are not far removed from those that instil religious belief in human beings. The leader of a herd – a female, whose sister had died some five years earlier – took the herd on a long detour to the place of her sister's death, and when they came upon her bones, the leader picked up her skull with great tenderness, whence the elephants passed it from one to another, caressing it with their trunks."

(from the book 'Shadows of the mind', Roger Penrose, p. 407)