Scientists have studied chimpanzees and other primates in captivity when long-time companions died. In Scientific American, Katherine Harmon examines the tentative answers of scientists to this question:
Link | Image: NIH
Another paper appearing in the same issue of Current Biology describes two mother chimpanzees carrying their dead infants in the Bossou colony in Guinea. Although this behavior has been observed in chimps and other primates before, the researchers, led by Dora Biro, a research fellow in the Department of Zoology at the University of Oxford, documented the carrying behavior for 68 days in one of the instances—far longer than had been previously described.
Of note, Biro's group reported, is that documented deaths of infants in that particular colony (of which there were three) always resulted in "extended carrying," though it is not universal that mothers carry infant corpses for weeks—or months—after death. This difference "raises questions about the potential role of observational learning in promoting chimpanzee mothers' prolonged transport of deceased young," Biro and colleagues wrote.
These differences in handling death might also be a part of demonstrated cultural differences among chimpanzee groups, Anderson says.
Link | Image: NIH
But the story is touching, none-the-less.
An interesting exploration of the topic can be found here.
http://www.wnyc.org/shows/radiolab/episodes/2010/04/02