Apparently “chimps are subject to contagious yawning”:http://www.newscientist.com/news/news.jsp?id=ns99996182 just like humans.

_The team played videos of chimps either yawning or exhibiting other open-mouth behaviours such as grinning to six adult chimps and three infants at the Primate Research Institute of Kyoto University in Japan._

_…They argue that their figure of 33 per cent of adults showing contagious yawning compares well with humans since the chimps do not understand the purpose of the trial._

_…”Our data suggest that contagious yawning is a by-product of the ability to conceive of yourself and to use your experience to make inferences about comparable experiences and mental states in others,” Gallup told New Scientist._