The Transient population of the Pacific Northwest has been identified as a distinct race. Their range encompasses the same waters as those used by the Resident Communities of Washington State, British Columbia and Alaska. No one understands how these two races developed, but most likely they have been genetically separated for over 100,000 years. Perhaps the last Ice Age brought about geographical separation… which encouraged separate breeding, and cultural and feeding traditions which have remained constant or evolved differently since that time.
Physically, the two races are very similar but there are some differences. The top of the dorsal fin of Transient orcas tends to be more pointed than that of Resident orcas. Less obvious, the saddle patch ( the grey pigmentation along the side & behind the dorsal fin ) is further forward on Transients.
The real difference between the two races is in their behaviors and habits concerning their food preferences. As mentioned, Resident whales prefer a diet of fish, and in the summer months almost exclusively salmon. This is why we can predictably watch the Resident populations in key locations along the coast during the salmon season (when the salmon are travelling to the rivers to spawn). Transients, however, prefer to eat marine mammals. The Transients cruise the coastal waters in search of their prey. Transients have been known to feast on Harbour seals, Sea lions, Dall’s porpoises, Harbour porpoises, Pacific Whitesided dolphins, Gray, Minke and other whales.
Their hunts are highly co-operative and coordinated efforts. Sometimes a hunt will take just minutes and at other times they last for several hours. Transients employ several hunting strategies. A lot of the time Transients travel around silently in small groups. This perhaps enables them to listen intently, lessen their presence in the water, and sneak up on their prey. The prey Transients are after have well developed skills of their own and are difficult and unwilling victims. So Transients have to use many different strategies to be successful. Once, a couple of Transients were.