Cannibalism, of course, is a special expression of the predatory motive in general, or it is mainly that. Cannibalism was certainly established early in primitive life, at least early enough to antedate all religion, and although its origin and history are shrouded in mystery, the motive was quite certainly practical. Evidently it was widespread if not universal. Whether it was introduced as a result of a failure of animal food, as some think, or has a still more simple explanation as a part of the original impulse which led men at a certain stage of their development to become hunters, cannot be determined. We know, however, that the alien human being was to some extent included under the same concepts as the animal enemy and prey, and presumably some of the strongest motives that led men to attack animals also included man as an object, since the alien group was regarded as in some degree different in kind from the in-group. It may have been in the great migrations when all the aggressive motives were increased that cannibalism became fixed as a habit. Cannibalism may well have been the primitive motive of warfare as serious deadly combat, but all predatory habits must have contributed to establishing a more or less habitual state of warfare among all groups of men. The predatory raid, with the reaction of defense, when carried on as a group activity in any form, is in fact war, so far as attack and defense were serious and deadly, and intelligence and weapons were sufficiently developed to make man a dangerous opponent. This predatory motive, of course, extended to all desired objects, and these objects must have included all objects that could most simply be acquired by stealing. They included food, women, and all other possessions. The custom of driving out young males from the group, by the jealousy of the old males, and of preventing males from obtaining females within the group must have been one of the earliest and one of the strongest incentives to predatory warfare. At first all property of the group, for so long as groups were wandering, was to some extent common, and attack and defense must have been common. The objects of predatory raids which produced group combat must have changed with the social life. When habitation became fixed and property therefore more individual, probably the predatory impulse itself became relatively a less important factor in combat.