What is taxonomy?
Interesting note: There are actually two subspecies of Dall's porpoises: Dall's porpoises (Phocoenoides dalli dalli) and True's porpoises (Phocoenoides dalli truei).
Dall's porpoises are black with a striking white patch on the belly and flank. They have a small triangular dorsal fin and the posterior margin of the tail flukes are fringed with a grayish-white band.
Sometimes it gets confusing when people use the words "dolphin" and "porpoise" because either word can be used to mean the exact same animals. These words often get mixed up by fishermen and scientists (though they may deny it!). However, each word refers to a specific family and should not be used interchangeably. Dolphins usually have beaks and more noticeable dorsal fins. Porpoises are usually smaller than dolphins and usually don't have pronounced melons or beaks. If you are lucky enough to look into a dolphin or porpoise mouth, you can tell the difference between the two families as dolphins have rather pointed teeth while porpoise teeth are shaped like spades. Unless you know a lot about dolphins and porpoises it is easy to confuse them.
- Dall's porpoises are fast swimmers and avid "bow wave riders." They often catch free rides on the bow-waves of passing boats.
- Dall's porpoises were named after William H. Dall, an American zoologist who was one of the first to identify the species through detailed notes and drawings.
- Dall's porpoises, when swimming at high speeds, create fan-shaped splashes of water, called "rooster tails" because the spray resembles a rooster's tail. Rooster tails are one way that scientists identify Dall's porpoises.
What should I know about Dall's porpoises?
- Where do Dall's porpoises live?
- How many Dall's porpoises are there?
- How can I identify a Dall's porpoise?
- How well can a Dall's porpoise see or hear?
- What do Dall's porpoises eat?
- How do Dall's porpoises have their young?
- How long do Dall's porpoises live? How do they die?
- Where can I find more information about Dall's porpoises?
Dall's porpoises only live in the North Pacific Ocean from Japan to Southern California and as far north as Bering Sea.
We don't know. Although population numbers are unknown, Dall's porpoises appear abundant through their range. Dall's porpoises are not considered endangered.
You can read more about Dall's porpoise stocks in the NMFS Alaska and Atlantic stock assessment reports.
Dall's porpoises are beautiful! Though individual animal coloring varies slightly, Dall's porpoises are easy to identify as they are mostly black with white along their sides, on the top half of their dorsal fins and on the trailing edge of their flukes. Dall's porpoises mature to around 7 feet (2.1 meters) long and have 19-23 spade-shaped teeth. When swimming, Dall's porpoises leave a characteristic splash called a 'rooster tail.'
Scientists don't really know. Captive Dall's porpoises emit low frequency clicks that are presumably used for echolocation.
Dall's porpoises are thought to have a rather varied diet consisting of hake, squid, lanternfish, anchovy, sardines and small schooling fish.
Female Dall's porpoises reproduce at approximately six years of age while male Dall's porpoises mature at 8 years of age. Dall's porpoise calves are born in mid-summer after a 12 month gestation period. They are about 3 feet (0.9 meters) long. Calves and their mothers live separate from main porpoise herds for a time. Dall's porpoise mothers usually have calves every 3 years.
Dall's porpoises usually live about 16-17 years. Very little is known about their mortality however many believe that Dall's porpoises are very susceptible to "incidental" capture by certain types of fishing gear. These porpoises become so intense upon the pursuit of their food that they fail to anticipate or see gill nets set for fish. Porpoises that get entangled in nets usually drown.Where can I find more information about Dall's porpoises?
Books and the world wide web are excellent places to learn more about marine mammals.
- Leatherwood, Stephen. Reeves, Randall R. Foster, Larry. The Sierra Handbook of Whales and Dolphins. Sierra Club, San Francisco, CA. 1983.
- Leatherwood, Stephen. Reeves, Randall R. Perrin, William F. Evans, William E. Whales, Dolphins, and Porpoises of the Eastern North Pacific and Adjacent Arctic waters; A Guide to their Identification. Dover Publications, Inc., New York, NY. 1988.
- Wynne, Kate. Folkens, Pieter. Guide to Marine Mammals of Alaska. Alaska Sea Grant Program. University of Alaska Fairbanks, Fairbanks, AK. 1992.
World Wide Web
- NMFS Stock Assessment Report
- The American Cetacean Society.
- The Animal Diversity Web.
There are many more sources to learn about cetaceans. Check with MML's online library or your local librarian for her or his recommendations.
This portion of the MML website is intended for a student audience and their educators.
Information within the education website should not be cited in scientific journals or publications.