It is believed that members of the pack selflessly subordinate their own interests to the greater interests of the pack, but this is really not a clear description of the evolutionary forces or causes at work. In wolf packs of the group establish their own social rankings. The top male and top female irately disrupts any attempts by their inferiors to breed. These rankings are usually stable for a long time, and when this is the case the lower-ranking animals often give way to their superiors without a brawl.