A new paper has come out indicating that Orcas’ evolution has been partially driven by culture. There are ten ecotypes worldwide. They each have different prey, look a little bit different, but most importantly their behavior differs between each ecotype as well. This stems from the fact that many of their behaviors are learned behaviors including hunting methods, communication, and socialization activities. The distinct ecotypes have developed different forms of a lot of these learned behaviors like communication vocalizations and hunting methods. It’s easy to see some of these differences between the two ecotypes here – the Residents and Transients. The easiest difference is that the Transients travel in smaller groups, usually one family, where Residents will travel in large pods of multiple related families. But even among different families of the same ecotype can show distinct differences as you watch multiple families for long enough.
Today we headed north to go check out some Transient Orcas on the west side of San Juan Island. As we neared this group we could see that it was two families of Transients travelling together! These were the T75’s and T77’s (The alphanumeric codes refer to the oldest female in the family who is the matriarch and usually the mother to all the others in the group). There were seven in total and as we watched them eat at least one meal, and then seemed to be trying to herd a group of Harbor Porpoises (one their menus). This was super interesting! Harbor Porpoises usually travel alone, but this was a group of almost 10 speedily trying to escape the orcas. The orcas seemed to work the porpoises into a group and keep them swimming as they swam in a zig-zag formation pushing them into a group and towards the island. So cool! We soon had to head back, but we stopped to look at some Harbor Seals and Steller’s and California Sea Lions! Whale folks, until next time.
Naturalist Erick
M/V Sea Lion