Across all the worlds oceans there are at least 10 ecotypes of orcas, and possibly even more. An ecotype is a distinct population of animals separated by diets, region, or social factors from the whole species. Currently there is only one Orcinus Orca, but some argue that is it time to give separate species names to some of these ecotypes.
Here in the Pacific Northwest, we have what are known as resident orcas. Resident orcas diverged genetically about 13,000 years ago. This means that their genes are completely different from that of other orca ecotype! In the wild, different ecotypes do not cross bread and often avoid each other. Resident orcas are separated by diet, which consists of 90% salmon here in the San Juans, and family grouping. Resident orcas travel is large family groups made up of matrilines. These family groups, or pods, can consist more than 40 members!
Another ecotype often spotted in the San Juans, are transient orcas. Transient orcas are marine mammal eaters and tend to travel in smaller groups. Since their prey is harder to catch, it is advantageous to travel in a group of 3-6 animals, but sometimes transient orcas will travel solo or in groups of 15 or more! Researchers think that we are starting to see the transient orca population become prey specific. Since hunting is passed down from mother to offspring, if the mother does not know how to hunt a minke whale, then neither will the offspring. It is possible that we will start seeing specialized hunting tactics by transient orcas, and only some will hunt minke whales, and others porpoises, and still other seals.
Offshore orcas also inhabit the waters of the PNW, but very little is know about this ecotype of orca. Since they travel off shore, hence the name, they are hard to spot. It is believed that this group feeds mostly on pelagic sharks and large schooling, fish such as tuna.
The more we are able to observe these creatures in the wild, the more we understand what makes each group different and unique. Only time will tell if there are more ecotypes to be discovered!
Naturalist Emily