From Scientific American:
In the wild, chimpanzees have been known to hunt together, particularly when conditions dictate that a solo hunter will not be successful. Yet this does not prove that our nearest living relatives understand cooperation the same way that we do: such group hunts may simply be the product of independent and simultaneous actions by many individuals with little comprehension of the need for coordinated action to ensure success. A new study, however, shows for the first time that chimpanzees understand when cooperation is needed and how to go about securing it effectively. And another study shows they might even be willing to cooperate without hope of reward.
More here.