Written by: Megan, Naturalist
On one of those glorious days when the sun is shining and the sea is glassy, I often tell my guests to look for porpoises. The most popular question that follows is what is the difference between porpoises vs. dolphins?
If we look at it generally it all comes down to genealogy and classification.
All whales, dolphins, and porpoises come under the genus Cetacea (the Latin word for Cetacean); this is then split into two categories. Odontocetes (Toothed Whales) and Mysticetes (Baleen whales). All dolphins and porpoises come under Odontocetes, but they come from two different families Delphinidae (Dolphins) and Phocoenidae (Porpoises).
There are 40 species in the dolphin family, here in the Salish Sea we have two: Pacific white-sided dolphins and orcas.
There are only seven species of porpoise and again we have two; Harbour porpoises and Dall’s porpoises.
If you look at it from a localised perspective the differences between porpoises and dolphins in the Salish Sea range from size, appearance and even habitat range.
Our dolphins are larger, Pacific white-sided dolphins can range in length up to 2.5m and weigh up to 400 lbs. Orcas are the largest of the dolphin family at a maximum length of 8m and a body weight of up to 1200 lbs. They have longer pointier rostrums (their beak-shaped mouth) and their teeth are pointy and conical shaped. They also have more curvy dorsal fins. They tend to be more friendly, with a higher chance of boat interactions and display more acrobatic behaviour. But this depends on the species and the individuals!
Whereas orcas can be seen anywhere in the Salish Sea, Pacific white-sided dolphins are seen more up the Northern end of Vancouver Island
In terms of porpoises, we have Harbour porpoise and Dall’s porpoise. Dall’s porpoises are up to 2m and 300 lbs. They have more of a dolphin temperament choosing to bow ride the boats. However, they are more of a pelagic species which means that they prefer the open ocean and so travel out into the Pacific, all the way to Japan. Due to the high whaling commission in Japan, it is suspected that they are being caught there, and we have subsequently seen a decline in our Dall’s population over the years.
Harbour porpoises are the most abundant cetacean in the waters of British Columbia but they are also the smallest at 1.5-2m and 130 lbs. They are very shy often hanging out in smaller groups although recently they have been seen in larger aggregations of over 100 (you can read more about this in our whale watching report on Harbour porpoises.)
Porpoises have rounder, shorter-shaped rostrums, and more triangular dorsal fins and their teeth are flat and spade-like.
If you would like to learn more about cetaceans found in our coastal waters, check out our guide on other porpoises and dolphins.
For a chance to see any of these species, book a whale watching tour.