Transient Vs. Resident Orcas

By | March 4, 2015

Photo credit Destination360 San Juan Islands Whale Watching http://www.destination360.com/north-america/us/washington/san-juan-islands/whale-watching

One of the biggest draws for tourists to the San Juan Islands are the orca whales (Orcinus orca) that frequent local waters. Most people are familiar with the appearance of orcas: their tall, triangular dorsal fins, grey saddle patches, and white eye spots are obviously identifiable characteristics. These charismatic marine mammals are not only entertaining to watch, but there is much more to them than meets the eye. Did you know that, worldwide, all orca whales are the same species, but there are unique subgroups within the species, similar to the different races that make up the human species?

Photo Courtesy of destination360.com

Photo Courtesy of destination360.com

The two distinct groups of orcas that you may encounter while cruising in the San Juans are the residents and transients. Resident orca whales frequent coastal waterways from spring until fall, and tend to live in matriarchal multifamily groups. Their most distinguishing characteristic is their fish-based diet, made up primarily of Chinook salmon. Residents also tend to be much more vocal than the transients. They are the ones you are most likely to hear over the Lime Kiln hydrophone. Transients live in smaller groups, mostly consisting of a single matriline. Their home range tends to be much larger than that of the residents, and they only sporadically visit inland waters. Transients hunt mammals, and as a result they are quieter which allows them to sneak up on their prey. Prey species in the Salish Sea, including harbor seals, can tell the difference between the vocalizations of residents and transients; they don’t react when residents are nearby but will show avoidance behavior (such as hauling out) when they hear transients.

Photo courtesy of movieposterskey.com

Photo courtesy of movieposterskey.com

Each individual group of orcas, whether they are transients or residents, have their own vocalization patterns that scientists call dialects. One pod cannot understand a different pod’s dialect, making the dialects very similar to human languages. Each pod also uses unique hunting techniques that they pass down from mother to offspring. This teaching and learning behavior is the closest thing to human culture that has been observed in the animal kingdom.

The orcas are certainly a favorite sight around the San Juan Islands. If you see a cluster of boats that are all stopped and pointing in the same direction, you’ve likely stumbled in to a fantastic whale watching opportunity. Also take a look at the map below, which shows the best places around the San Juans to spot the residents. Just remember to be whale wise when observing them, and share your pictures on our Facebook page!

Map courtesy of sanjuansafaris.com

Map courtesy of sanjuansafaris.com

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