When people speak of ‘the law of the jungle’, they usually mean unions restrained and ruthless competition, with everyone out solely for his own advantage. But the phrase was coined by Rudyard Kipling, in The Second Jungle Book, and he meant something very different. His law of the jungle is a law that wolves in a pack are supposed to obey. His poem says that ‘the strength of the Pack is the Wolf, and the strength of the Wolf is the Pack’, and it states the basic principles of social co-operation. Its provisions are a judicious mixture of individualism and collectivism, prescribing graduated and qualified rights for fathers of families, mothers with cubs, and young wolves, which constitute an elementary system of welfare services. Of course, Kipling meant his poem to give moral instruction to human children, but he probably thought it was at least roughly correct as a description of the social behaviour of wolves and other wild animals. Was he right, or is the natural world the scene of unrestrained competition, of an individualistic struggle for existence?