digplanet beta 1: Athena
Share digplanet:

Agriculture

Applied sciences

Arts

Belief

Business

Chronology

Culture

Education

Environment

Geography

Health

History

Humanities

Language

Law

Life

Mathematics

Nature

People

Politics

Science

Society

Technology

For other uses, see Porpoise (disambiguation).
Porpoises
Temporal range: 15.970–0Ma
Miocene to Recent
Harbor.Porpoise.4.jpg
Phocoena phocoena, harbour porpoise near Denmark
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Cetacea
Suborder: Odontoceti
Superfamily: Delphinoidea
Family: Phocoenidae
Gray, 1825
Genera

See text

Porpoises (/ˈpɔrpəs/; also called mereswine) are small cetaceans of the family Phocoenidae; they are related to whales and dolphins. They are distinct from dolphins, although the word "porpoise" has been used to refer to any small dolphin, especially by sailors and fishermen. The most obvious visible difference between the two groups is that porpoises have shorter beaks and flattened, spade-shaped teeth distinct from the conical teeth of dolphins.

The name derives from French pourpois, possibly from Medieval Latin porcopiscis (porcus pig + piscis fish; cf. classical porcus marīnus ("sea hog").[1]

Porpoises, divided into six species, live in all oceans, and mostly near the shore. Freshwater populations of the finless porpoise also exist. Probably the best known species is the harbour porpoise, which can be found across the Northern Hemisphere. Like all toothed whales, porpoises are predators, using sounds (echolocation in sonar form) to locate prey and to coordinate with others. They hunt fish, squid, and crustaceans.

Taxonomy and evolution[edit]

Porpoises, along with whales and dolphins, are descendants of land-living ungulates (hoofed animals) that first entered the oceans around 50 million years ago (Mya). During the Miocene (23 to 5 Mya), mammals were fairly modern. The cetaceans diversified, and fossil evidence suggests porpoises and dolphins diverged from their last common ancestor around 15 Mya. The oldest fossils are known from the shallow seas around the North Pacific, with animals spreading to the European coasts and Southern Hemisphere only much later, during the Pliocene.[2]

Suborder Odontoceti toothed whales

Recently discovered hybrids between male harbour porpoises and female Dall's porpoises indicate the two species may actually be members of the same genus.[6]

Physical characteristics[edit]

A harbour porpoise at an aquarium.

Porpoises tend to be smaller but stouter than dolphins. They have small, rounded heads and blunt jaws instead of beaks. While dolphins have a round, bulbous "melon", porpoises do not. Their teeth are spade-shaped, whereas dolphins have conical teeth. In addition, a porpoise's dorsal fin is generally triangular, rather than curved like that of many dolphins and large whales. Some species have small bumps, known as tubercles, on the leading edge of the dorsal fin. The function of these bumps is unknown.[6]

These animals are the smallest cetaceans, reaching body lengths up to 2.5 metres (8.2 ft); the smallest species is the vaquita, reaching up to 1.5 metres (4.9 ft). In terms of weight, the lightest is the finless porpoise at 30 to 45 kilograms (66 to 99 lb), and the heaviest is Dall's porpoise at 130 to 200 kilograms (290 to 440 lb). Because of their small size, porpoises lose body heat to the water more rapidly than other cetaceans. Their stout shape, which minimizes surface area, may be an adaptation to reduce heat loss. Thick blubber also insulates them from the cold. The small size of porpoises requires them to eat frequently, rather than depending on fat reserves.[6]

Life history[edit]

Porpoises bear young more quickly than dolphins. Female Dall's and harbour porpoises often become pregnant with a single calf each year, and pregnancy lasts for about 11 months. Porpoises have been known to live 8–10 years, although some have lived to be 20.[6]

Behavior[edit]

"Rooster tail" spray around swimming Dall's porpoises

Porpoises prey on fish, squid, and crustaceans. Although they are capable of dives up to 200 m, they generally hunt in shallow coastal waters. They are found most commonly in small groups of fewer than ten individuals, referred to as pods. Rarely, some species form brief aggregations of several hundred animals. Like all toothed whales, they are capable of echolocation for finding prey and group coordination. Porpoises are fast swimmers—Dall's porpoise is said to be one of the fastest cetaceans, with a speed of 55 km/h (34 mph). Porpoises tend to be less acrobatic and more sexually aggressive than dolphins.[7]

Humans and porpoises[edit]

Accidental entanglement (bycatch) in fishing nets is the main threat to porpoises today.[8] One of the most endangered cetacean species is the vaquita, having a limited distribution in the Gulf of California, a highly industrialized area. In some countries, porpoises are hunted for food or bait meat.[citation needed]

Porpoises are rarely held in captivity in zoos or oceanaria, as they are generally not as capable of adapting to tank life or as easily trained as dolphins.[citation needed]

See also[edit]

References[edit]

  1. ^ http://dictionary.reference.com/browse/porpoise?o=102213
  2. ^ Gaskin, David E. (1984). Macdonald, D., ed. The Encyclopedia of Mammals. New York: Facts on File. pp. 196–199. ISBN 0-87196-871-1. 
  3. ^ Ichishima, H. & Kimura, M.. 2005. "Harborophocoena toyoshimai, a new early Pliocene porpoise (Cetacea, Phocoenidae) from Hokkaido, Japan". Journal of Vertebrate Paleontology 25(3):655–664
  4. ^ Ichishima, H. & Kimura, M.. 2000. "A new fossil porpoise (Cetacea; Delphinoidea; Phocoenidae) from the early Pliocene Horokaoshirarika Formation, Hokkaido, Japan". Journal of Vertebrate Paleontology 20(3):561–576
  5. ^ Lambert, O.. 2008. "A new porpoise (Cetacea, Odontoceti, Phocoenidae) from the Pliocene of the North Sea". Journal of Vertebrate Paleontology 28(3):863–872
  6. ^ a b c d Read, Andrew (1999). Porpoises. Stillwater, MN, USA: Voyageur Press. ISBN 0-89658-420-8. 
  7. ^ http://appreviews4u.com/2013/03/11/porpoises-the-ignored-species/
  8. ^ http://www.iucnredlist.org/details/17028/0

External links[edit]

Media related to Phocoenidae at Wikimedia Commons


Original courtesy of Wikipedia: http://en.wikipedia.org/wiki/Porpoise — Please support Wikipedia.
This page uses Creative Commons Licensed content from Wikipedia. A portion of the proceeds from advertising on Digplanet goes to supporting Wikipedia.
62541 videos foundNext > 

Rare porpoise in danger of extinction

Rare porpoise in danger of extinction CNN's David McKenzie meets a critically endangered species in China and the scientists trying to save it. A new report ...

Dall's Porpoise

Dall's Porpoise in Prince William Sound, Alaska. Underwater footage using GoPro HD Hero2 and a Snake River Prototyping Blur Fix housing. Captured in 720p at ...

Vancouver Harbor Porpoise so cute :)

This was the cutest Harbor Porpoise ever at the Vancouver aquarium. He would follow my boyfriends finger around and he LOVED the camera. So cute.

Vaquita - Saving the Desert Porpoise

Vaquita porpoise in Mexico is marine mammal on the brink of extinction. Less than 200 animals remain and gillnets - nearly invisible fishing nets set for shr...

The Secret Life of Walter Mitty (2013) | "Not A Porpoise" | 20th Century FOX

Walter Mitty jumps into the freezing ocean and quickly discovers that the fin circling him in the water doesn't belong to a porpoise. Ben Stiller directs and...

Barbie Life in the Dreamhouse New Episodes 2014 - Accidentally on Porpoise

"Barbie", "Barbie Life in the Dreamhouse", "Barbie Life in the Dreamhouse Full Movie", "Barbie Life in the Dreamhouse full episodes", "Barbie Life in the Dreamhouse new episodes 2014", "Barbie...

The Monkees -Porpoise Song (Remastered, Restored, Re-envisioned) HD

The Monkees fabulous "Porpoise Song" in a new mix. Restored "Head" footage. Written by the great Carole King & Gerry Goffin. I do not own footage, photos or ...

Life in the Dreamhouse -- Accidentally On Porpoise | Barbie

Chelsea adopts new pet dolphins that get loose in the plumbing. Barbie leads the gang on a rescue mission. More videos and fun at http://www.Barbie.com/dream...

The Monkees - Head - Porpoise Song

The Second Song of the album Head by The Monkees. Lyrics My, my, the clock in the sky is pounding away And there's so much to say, A face, a voice, an overdu...

The Monkees - Porpoise Song (Theme From HEAD)

Psychedelic clip from the beginning of The Monkees' movie HEAD.

62541 videos foundNext > 

625 news items

Hernando Today

Hernando Today
Tue, 28 Oct 2014 12:55:49 -0700

Clearwater Marine Aquarium has begun an international conservation effort aimed at saving the vaquita porpoise, a species on the verge of extinction. The campaign, entitled “Winter's Hope for the Vaquita,” will create awareness and a call to action to ...

Mongabay.com

Mongabay.com
Wed, 22 Oct 2014 07:49:49 -0700

On the morning of July 14, 2002 Qi Qi ate breakfast as he always did. As the world's only captive baiji – or Yangtze river dolphin (Lipotes vexillifer) – Qi Qi was something of a celebrity in China and his caretakers kept a close eye on his health ...

Telegraph.co.uk

Telegraph.co.uk
Thu, 16 Oct 2014 13:58:17 -0700

Britain 'not doing enough to protect porpoise'. European Commission asks United Kingdom to designate protected areas for harbour porpoise. Harbour Porpoise (Phocoena phocoena) surfacing near the north end of the Isle of Coll, Agyll and Bute, Scotland ...
 
The Guardian
Fri, 17 Oct 2014 08:14:52 -0700

“Despite a large number of harbour porpoise in its waters, the UK has so far proposed only one small site in Northern Ireland [as a protected area], exposing some of the identified sites to the risk of offshore wind farm development,” a statement says.

Tampabay.com

Tampabay.com
Fri, 17 Oct 2014 04:55:20 -0700

CLEARWATER — Seeking to harness the fame of its dolphins, Winter and Hope, for a worthy cause, the Clearwater Marine Aquarium is launching a campaign to save a near-extinct species of porpoise.

Center for Biological Diversity (press release)

Center for Biological Diversity (press release)
Mon, 29 Sep 2014 08:22:30 -0700

The vaquita is the world's smallest porpoise and exists only in Mexico's Gulf of California. It has suffered a dramatic and alarming decline, dropping from 200 animals in 2012 to just 97 in 2014. Without help, scientists predict vaquitas could be ...

People's Daily Online

People's Daily Online
Fri, 24 Oct 2014 01:03:45 -0700

Photo taken on Oct. 22, 2014 shows the samples of finless porpoise in a museum in the Tongling National Nature Reserve for Freshwater Dolphins in Tongling City, east China's Anhui Province. Friday coincided with the International Freshwater Dolphin Day.

The Argus

The Argus
Mon, 27 Oct 2014 12:18:45 -0700

Laurence Koe and his family were visiting from London for the day and found the mammal buried in the shingle. Mr Koe, 40, said: “There was a group of about 15 or 20 of us in the end helping to dig the shingle out of the way. Initially we thought the ...
Loading

Oops, we seem to be having trouble contacting Twitter

Support Wikipedia

A portion of the proceeds from advertising on Digplanet goes to supporting Wikipedia. Please add your support for Wikipedia!

Searchlight Group

Digplanet also receives support from Searchlight Group. Visit Searchlight