Dall’s porpoises are speed demons. They suddenly appear, seemingly out of nowhere, and disappear the same way. Although they ride in both bow and stern wakes of boats, they seldom stay for very long. Most are fleeting encounters in which you catch glimpses of more splashes and flashes of black and white than seeing the animal swish it’s powerful tail as it zigs or zags. Their leaps are less frequent and much less acrobatic than those of the Pacific White Sided dolphin.
Dall’s tend to travel in small pods or groups of two to eight animals but every once in a while they have been seen in larger groups of around twenty-five, perhaps for mixing the gene pool. Since they zip about so quickly and in what looks like random back and forth patterns, getting a good count on the group can be a challenge, so is getting good photos. They do slow down occasionally, but again, not for very long.
As these porpoises speed through the water, they throw a rooster tail type of splash. This is quite distinctive as they shoot along just below the surface of the ocean. They are known to travel at around 30 knots (56 kph or 35 mph). With all this speed, I’ve often wondered how Transient Orca / Killer Whales manage to hunt and kill Dall’s porpoises.
These small chunky cetaceans have black and white markings that give them the appearance of a mini Killer Whale / Orca. There have been reports by people mistaking Dall’s porpoises for baby Orca, but the lack of white eye patches and a much smaller dorsal fin is definitely a Dall’s.
In the recent number of years, Dall’s porpoises have been mixing with Harbour porpoises and there are confirmed “hybrids” usually of a Dall’s female with a male Harbour porpoise. I have not heard of any the other way around. These “hybrids” have the speed characteristic of the Dall’s and the appearance of the Harbour porpoise.
Dall’s Porpoise – Phocoenoides dalli Specifics:
up to 2.2 m (7 ft)
up to 220 kg (485 lbs)
Black with large white flanks
White on dorsal fin (occasionally all white)
Usually bit of white on tail fluke edges
No beak very small head
Chunky body head to tail
Short pectoral flippers
Triangular dorsal fin mid back
No white eye patch like Killer Whale / Orca