Haunting picture proof that chimps really grieve.

United in what appears to be deep and profound grief, a phalanx of more than a dozen chimpanzees stood in silence watching from behind the wire of their enclosure as the body of one of their own was wheeled past. 
This extraordinary scene took place recently at the Sanaga-Yong Chimpanzee Rescue Center in Cameroon, West Africa. 

http://www.dailymail.co.uk/sciencetech/article-1223227/Is-haunting-picture-proof-chimps-really-DO-grieve.html#ixzz0VBEMsfRP