The Romans called them orcas, literally “demons from hell”. Spanish whalers
called them “whale killers” after their vicious and co-ordinated attacks on other whales, and now they are called killer whales or simply orcas. Having received some pretty bad press over the years, their image has improved
recently as a result of research which has shown that they are intelligent, social creatures, and harmless to humans.
There are, in fact, three distinctly different orca types; residents, transients, and offshores. Residents are the most studied because they do not stray very far from their home territory during summer, and they return year after year to the same area. Transients roam over a larger coastal area than the residents, and travel in smaller groups, sometimes hunting and traveling as a pair. Very little is known about offshores at this time. They are known to travel in large groups of up to 60 individuals, and they seldom venture into protected waters.
The majority of orcas in Johnstone Strait are residents, but transients are seem at times. The major difference between the two sub-species is diet. Residents have adapted to a diet of fish, mostly salmon. Transients appear to feed exclusively on seals, sea lions, and porpoises. They have been even known to enjoy the occasional deer and moose, as these will swim narrow coastal channels. These feeding patterns explain the high resident population in Johnstone Strait. Between June and September, thousands of salmon pass through the confined strait on the way their spawning grounds.
On the whole, the numbers of orcas of Johnstone Strait are increasing at a 2.5% rate per year to a believed healthy total of 200.
* it is possible to identify orcas by unique markings on their dorsal fins and the
appearance of a “saddle” patch at the base of the fin.
* Orcas are unique in that family units stay together and do not disperse. A maternal group may contain four generations whose ages could well parallel a human family. Females may reach an age of 80, and usually give birth around 15. Orcas belong to a matrilineal genealogy, that is, an individual’s ancestry is traced through it’s mother and her relatives. To avoid inbreeding it is thought that males mate with cows in other pods, so paternity is usually not known.
* Orcas identify each other and other groups by vocalization called dialects. These high pitched squeals, squawks and screams form their “language”.