 The feeding specializations of these toothed whales are proposed to have led to the divergence of the sympatric "resident" and "transient" forms of killer whales off Vancouver Island, in which resident killer whales feed on fish and squid, and transient whales feed on marine mammals.Vocalizations have also been proven to be culturally acquired in killer and sperm whale populations, as evidenced by the distinct vocalization patterns maintained by members of these different species even in cases where more than one species may occupy one home range.Further study is being done in the matrilineal whales to uncover the cultural transmission mechanisms associated with other advanced techniques, such as migration strategies, new foraging techniques, and babysitting.