Orca Whales

Orca is the name scientists prefer to call a killer whale.

Three distinct populations of orcas or killer whales

There are three different orca whales. These three orca whales groups seem to be different genetically, and with very different feeding habits. Not only, these different orcas do not interact socially, they seem to avoid contact with each other. The three orca populations are:

• Offshore orca

• Resident orca

• Transient orca

Offshore Orca Whales

Offshore orcas live in the open ocean, travel in pods and seem to eat only fish. Perhaps they feed on schooling fish. Orce whales have been found to travel in very large groups of 25 - 60 in continental shelf waters, some ranging from California to Alaska and probably out to hundreds or perhaps thousands of miles offshore.

Offshore orca whales appear to be more closely related to the resident orca whales genetically, although distinct. Many details about offshore orcas are still unknown, as they were only discovered in the early 90's.

Resident Orca Whales

Resident orcas feed primarily on salmon and travel in pods of six to 50 whales. Resident orcas follow the salmon migration routes in the summer and disperse in the winter, but can typically still be seen all year long. A resident pod may travel up to 800 kilometres.

Transient Orca Whales

Transient orcas feed on marine mammals including seals, whales and sea birds and travel in small groups of one to five whales. Optimum pod size for transients is three, so whenever a third offspring is born, one of the older siblings must leave. The rule seems to be that the eldest son can stay, but all but one of the others may have to go.

Transient killer whale pods are generally comprised of an adult female killer whale and two or three of her orca offspring. Among the differences between resident orca whales and transient orca whales are that while resident orcas of both sexes stay within shouting distance of their mothers their entire lives, only first-born male transients maintain such intense fidelity to their mothers.

Transient orcas' range extends up to 1450 kilometres. They are found on the coast year-round, but are not common or predictable at any time.