What is black and white and lives in the sea and is the fastest of its kind in the world?
If you guessed a cetacean (the grouping of animals that includes dolphins and whales), you are right. But if you guessed the famous Orca (or killer whale), you were close, but not quite there. While the above description could in a sense fit the Orca; that animal is fast, but not the fastest to be found. That title is held instead by a much lesser known cetacean, a porpoise.
And yes, a real porpoise, not a dolphin with an identity problem. Contrary to popular thought—and confusion—the terms “dolphin” and “porpoise” are not completely synonymous. Oh sure, the latter term is commonly used instead of the former, but often simply because it is more “fun to pun” by using “porpoise on purpose.”
True porpoises are the six species of the cetacean family Phocoenidae. These are distinguished from members of dolphin families Delphinidae (ocean dolphins) Stenidae (coastal dolphins) and Platanistidae (river dolphins) by their blunter snouts (no bottlenoses here!) and their relatively smaller size (usually less than six feet in length). Their teeth also differ in that they are spade-like rather than pointed or conical; several of the cervical vertebrae are often fused, but these features are not likely to be noticeable to the average person. Most porpoise species also tend to be more reclusive than dolphins, shying away more from people and boats.
Again, this is most, but not all. The Dall’s Porpoise (Phocoenides dalli), in contrast, has been described as being as being “hyperactive” and “thrilling.” Often, if it detects the presence of a boat, it will bolt towards it with incredible speeds and then stay with it for maybe a half-an-hour or an hour or longer.
The Dall’s Porpoise is the largest of all porpoises. It is typically about six-feet long, but one close to eight feet was recorded from California. Rather than being trim and sleek, this mammal is rather plump, often weighing in at close to 450 pounds. But, actually, it well exemplifies the original meaning of the word “porpoise” or “pig-fish” (which was given back in the days when fish meant any marine animal).
And this chunky “sea-pig” is perfectly shaped for one thing—speed! Its big body is deeper than it is wide. It has a small head and fins just in the right position to zip through the water. It also has a ridge behind its dorsal fin and more vertebrae than any other cetacean. All of these enable the Dall’s Porpoise to reach 30, even 35 miles per hour—faster than any other mammal in the ocean!
Although this heavy-weight of the sea can’t quite jump all the way out of the water like its sleeker dolphin cousins, it is one of the most exciting sights when seen in its natural environment. It is so fast that when it breaks the surface to breathe, it creates a plume of water to trail behind it. Its coloration is even an exciting sight, being a bold black-and-white rather than just a dull gray. (Its alternate common name is “White-flanked Porpoise” because of the large white patch near its tail; Dall’s, in honor of nineteenth century zoologist, William Dall is the preferred appellation.)
When not wowing whale-watching expeditions or other boaters, Dall’s Porpoise will hunt for squids and schooling fishes. But with its tremendous ability to zip through the water, it can also descend down to 10,000 feet and grab laternfishes or some other type of deepwater “bite to eat.”
Not too many other creatures, though, succeed in taking a bite out of the Dall’s Porpoise; it is just too quick to catch! Every once in a while, an Orca may get lucky and nab one, but aside from that, its only enemy is man. Because it is not strictly a coastal species, as are other porpoises, Dall’s is often caught by pelagic fishers. An exact “nose-count” is hard to come by for such a fast mover, but it is known that its numbers are going down and there is enough concern that this species is listed by the World Conservation Union (IUCN) to list it as not quite endangered but as “LR/cd” (lower risk/conservation dependent.)
At present, Dall’s Porpoise still ranges across the entire Northern Pacific, from Japan to central Baja California. There is a slight difference in coloration between those of different regions, leading some people to theorize that there may be distinct subspecies or races. Since it prefers cooler waters, it is largely seen in Arctic waters and only off of California in the fall and winter.
While the Dall’s Porpoise is not an overly social species, it is usually seen in small pods of ten individuals or less. Sometimes they will be in groups of hundreds. The biggest ever recorded was over 3,000 individuals off of Southeast Alaska. But no matter how many are seen or where they are found, Dall’s Porpoises are the undisputed thrill-seeking, people-thrilling speeders of the sea.