Answer:
Apes mourn the loss of those that were close to them. Much like humans, the way they mourn varies in each individual. In one case, a chimp refused food for a few days and would not leave her nest while grieving the loss of her male counterpart.
read this article:
http://abcnews.go.com/Technology/AmazingAnimals/chimps-mourn-passing/story?id=8937053&page=2