Resident killer whales
Resident killer whales on the BC coast are divided into two groups referred to as the northern resident and southern resident communities.
These two communities are in fact distinct populations that differ behaviourally, genetically and culturally. There is some geographical overlap between the ranges of northern and southern residents. However, the two communities are very seldom observed in the same area at the same time and have not been seen to interact with one another. Mating between the two groups is not believed to occur.
Resident killer whales are Chinook salmon specialists.
Resident killer whales live in complex matriarchal society, in which both males and females remain with their mother indefinitely, even after they have offspring of their own. These bonds between sibling usually remain strong even after the mother has died. Family units stemming from a living or recently-deceased matriarch are called matrilines.
To learn more about the social structure of resident killer whale communities click here.
Resident killer whales use echolocation frequently.
While both northern and southern communities range throughout the BC coast, this map illustrates the primary range used by each population.
Resident killer whales are salmon specialists. Ninety six percent of their summer diet is made up of salmonid species. For the majority of the year they feed primarily on Chinook salmon (also referred to as spring or king salmon). When Chinook salmon are scarce, they expand their diet to include chum and coho salmon, other fish, and squid. Resident killer whales will eat 50-150 kg of fish per day. Recent research by Graeme Ellis has shown that resident killer whales share the majority of their prey with other members of their family. There is no evidence that they prey upon any mammals or birds.
Resident killer whales often find their prey with echolocation, also known as biosonar. Echolocation works just the way the name suggests—the whales produce loud clicking sounds and listen for the echos. The whales use this echolocation frequently to build a picture of their surroundings to locate food or navigate underwater.
Killer whales use sounds for communication as well as to find prey. Their scream-like calls carry for great distances and allow residents to remain in contact with group members, and announce their presences to non-group members. See Communication to learn more about echolocation and communication in killer whales.
Learn more about the northern resident killer whales here and southern resident killer whales here.