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Porpoises
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Kingdom:
Animalia
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Phylum:
Chordata
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Class:
Mammalia
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Order:
Cetacea
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Family:
Phocoenidae
Approximately 78 species of whales,
dolphins, and porpoises are included in the Order Cetacea. Cetaceans are broken
into two Suborders, or main groups, Mysticeti (baleen whales) and Odontoceti
(toothed whales). There are 11 species of baleen whales and 67 species of
toothed whales. Cetaceans are relatively large, generally characterized by
streamlined bodies that glide easily through the marine environment.
harbour porpoise
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.
Members of the porpoise, or the
Phocoenidae family, have blunt heads and small spade-shaped teeth. Porpoises
grow up to 7 feet (2.1 meters) in length a. Porpoise species include the
harbour porpoise, Gulf of California porpoise,
Burmeister’s porpoise
Dall’s porpoise
finless porpoise
spectacled porpoise
Incidental mortality in fishing gear
is the most immediate threat facing porpoises other human activities represent
potential dangers to this population. Foremost among these is continued
degradation and loss of habitat. Threats to porpoise habitat may be a direct
result of human activities (e.g. porpoises excluded from habitat by coastal
development such as salmon farming) or occur indirectly, through the effects of
pollution and eutrophication in coastal ecosystems.
Image Credits:FAO Fisheries Global Information
System
For more information on Whales,
Dolphins and Porpoise click on the logos below
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