The view of Neanderthal life as unusually violent and dangerous relies largely on case studies of Neanderthal skeletons that showed a high number of injuries, especially head injuries. As possible causes for these injuries, scholars have pointed to violent social behavior, the risks of a highly mobile hunter-gatherer lifestyle in difficult Ice Age conditions and attacks by carnivorous animals such as bears or hyenas. Neanderthals are thought to have used close-range, non-projectile hunting weapons, like thrusting spears, which would have brought them dangerously close to their prey.