Dall’s porpoises—they’re lean mean speeding machines. Known for its agility and playfulness, this species is often mistaken for a harbour porpoise or a baby killer whale. Since they seem to be lesser known than their other Salish Sea friends, it’s time to shine the spotlight on this engaging black and white speed demon.
Here are seven things that may surprise you about Dall’s porpoises.
1. They’re big (ish)
Dall’s are the largest porpoise in the world! Porpoises are the smallest members of the cetacean family. Measuring up to 2.4 metres (8 ft.) and 200 kg (440 lb.) is impressive when compared to their smaller counterparts. In constrast, the world’s smallest porpoise, the endangered vaquita (endemic to Mexico), is only 1.2 metres (4 ft.), and 43 kg (95 lb.).
2. They’re faster than a speeding bullet
Well okay, perhaps not quite that fast. But they can swim up to 55 km per hour! Swimming this speed near the ocean’s surface produces their iconic “rooster tail” of bursting sea spray. They’re one of the few animals that can outswim a killer whale—a rare and impressive feat. They can sprint at the same speed as the killer whale which gives a Dall’s porpoise about a 50% chance of escaping—but also a 50% chance of becoming a tasty snack!
3. They love surfing
Dall’s porpoises can be playful around boats and other whales. They often race directly toward boats of all sizes to play in their bow waves or wakes. Dall’s are so hardcore they’ll even brave the deafening roar of a container ship to ride the sweet waves it leaves in its path!
Dall’s porpoises not only interact with boats, but also other species of whales. They’ve been seen swimming with humpbacks and fin whales! These gentle giants are particularly attractive when they swim quickly enough to produce waves. The phrase “bow riding” may refer to whales interacting with boats, but it seems Dall’s will happily bow ride a whale if there’s nothing else around!
4. They sometimes “get frisky” with harbour porpoises
Dall’s porpoises are a distinct species, yet harbour and Dall’s porpoises do hybridize. Usually the Dall’s porpoise is the mother and the harbour porpoise is the father. Male harbour porpoises are much more promiscuous than Dall’s, and they want to find as many lady porpoises as possible—regardless of the species, it seems. Hybrid porpoises may make up 1-2% of the entire Dall’s population off southeastern Vancouver Island!
Male Dall’s porpoises have an entirely different strategy. In a behaviour known as mate-guarding, they’ll stick with their lady friend to prevent other males from getting a chance with her!
5. They’re hunted by more than killer whales
Dall’s porpoises are somewhat successful at escaping killer whales. But unfortunately they’re still hunted in the western Pacific for human consumption in Japan. Thousands are slaughtered each year in the Japanese harpoon hunt and thousands more die annually in the Japanese drift net fishery. There is ongoing concern about the sustainability of this level of exploitation in the region.
Dall’s were not targeted by commercial whalers in BC, although some have been entangled and killed by fishing gear. Despite the wide variation in population estimates—as high as 1.2 million but it could be much lower—Dall’s porpoises are considered a species of “least concern” by the IUCN Red List of Threatened Species.
6. They’re named after an American naturalist
William Healey Dall (pronounced “dawl”) was a naturalist and paleontologist in the mid-19th century. Dall’s porpoises are named in his honour, along with several mollusk species and a type of sheep! Contrary to popular belief, he did not name the Dall’s porpoise after himself. A friend of his at the (now) Smithsonian wanted to recognize his hard work in the field.
7. They’re natural sopranos
Ever heard a Dall’s porpoise vocalize? We’re guessing not. Their echolocation clicks are so high-pitched that we can’t hear them! Neither can killer whales which of course is another crafty way for Dall’s to avoid getting eaten. Fortunately, we have technology to help us hear what they sound like. Listen for yourself!
Find out more about Dall’s porpoises and other porpoises in the world from the Porpoise Conservation Society, one of the conservation and research organizations we support through our per guest Wildlife Fee and 1% for the Planet.
As part of our research mandate, we also assist BC porpoise researcher Anna Hall by contributing on-water data to her studies on the distribution and abundance of Dall’s and harbour porpoises in the Salish Sea.
Come out with us on a tour and you could see a porpoise for yourself! To book a tour give us a call or book online!
Blog written by Eagle Wing naturalist Lili Wilson.
Published Aug. 22, 2021.