- ,
To see pictures of animals click the blue dot..
The porpoises are among the smallest of the aquatic mammals. They resemble dolphins but are smaller and have rounded rather than beak shaped, snouts.. They are believed to have emerged as a group of aquatic mammals about 15 million years ago. from these beginnings evolved six separate species of porpoise. Today, they are found mainly in coastal waters of the Northern Hemisphere. In some parts of the world dolphins are referred to as porpoises, which sometimes cause confusion.
Habits: The porpoises are found mainly in coastal waters, often entering harbors and estuaries and swimming up rivers. The common, or harbor porpoise, in habit temperate and cold inshore waters of the Northern Hemisphere around western Europe, northern Asia, and northern America. The California Gulf porpoise, or cichito, inhabits not only the Gulf of Guinea but also the black sea. Burmeister';s porpoise is found in the Southern Hemisphere, living in the cool, shallow inshore waters off South America and around the Falkland and South Georgia islands. Dall's porpoise, the most active and sociable species, is found around northern Japan and off the coast of North America, from the Aleutian Inland to California. The finless porpoise, the only true tropical species, frequents the Indo Pacific Ocean from Iran to Borneo and Japan..
Breeding: The porpoises do not thrive in captivity, and studies of porpoises in their natural environment had been very limited. As a result, little is known about their breeding habits. In the Northern Hemisphere mating appears to take place in the summer, with a single calf born almost a year later. At birth the calf is about half the length of a female. It is brought to the surface immediately for its first breathe. For a few days after giving birth, the female swims on her side while nursing her calf, so they can reach the surface at the same time to breathe. Soon the calf surfaces on its own and dives to resume feeding. Most species nurse for six to eight months, but the Dall's porpoise nurses up to two years. A female with a young calf tends to leave the group, but they may join another mother and her young. The calf swims just in front of its mother's dorsal fin and often remains with her after being weaned.
Food & Hunting: The porpoises often feed in river estuaries, over submerged seabed ridges, or where sea currents meet all places where fish congregate. Each species has it preferences, but they all flesh eaters. For example, the finless porpoise likes crustaceans, while the Dall's porpoise eats squid when ever possible. The common porpoise feeds on herring, sardines, and cod, which it often herds towards a slopping, sandy shore. A common porpoise needs 6 to 10 pounds of food a day, while the larger Dall's porpoise needs 20- to 25 pounds a day. Proposes often form small groups of two to four members, and they may drive individually for prey.. Usually they feed on small schools of fish, but if larger concentration of fish accrues, many groups will gather to feed. Proposes hunt mainly by sight and by listening for fish. They swallow prey whole and bite it into large chunks.
Key Facts: Sizes, Weight, Breeding, Lifestyle, Related Species
Height:
Length: 4 to 71/2 ft
Weight: 50 to 350 lbs
Breeding:
Sexual Maturity: 3 to 4 years depending
on species
Mating Season: Summer in Northern Hemisphere
Gestation: 10 to 11 months
No of young: 1 calf
Lifestyle:
Call: Forms groups of 2 to 20, but usually
about 4
Diet: Varied; mainly crustaceans, squid,
and many species of fish.
Life span: 12 to 23 years
Distribution: Porpoises live in coastal
waters almost throughout the north Pacific and western Indo Pacific.
They are also found in the temperate and sub Antarctic waters of South
America and around the Auckland Islands off New Zealand.
Conservation: Porpoises are threatened
by fishing nets and pollution. Some species are believed to be declining.
The Porpoise Family:
The Common, or harbor, porpoise:
Phoncoena phocoena: Usually dark on back and white on underside for camouflage
in coastal waters.
California Gulf Porpoise:P. sinus , is
similar in appearance, but darker.
Dall's Porpoise: Phoncoenoides dalli:
muscular body. Jet black back; white patch on belly and flanks. Dorsal
fin and flukes tipped white.
Spectacled Porpoise:Phoncoenadiotrica;
Blue black back; white sides and under parts. Rim around eyes like spectacles.
Finless Porpoise:Neophoecaena phocaenoides;
All gray except for paler "throat" and face. rounded, blunt head.
No dorsal fin.
Burmeister's Porpoise;Phocoena spinnipinnis;
All dark. Dorsal back fin has sharp point with "teeth" on leading edge.
Did you know:
Dall's porpoise is the faster of all porpoises.
It speeds through the water at 12 to 15 knots. It is famous for these
"rooster" spray a stream of water that arcs up over the head as it surfaces.
The finless porpoise, as its name suggests, has
no dorsal (back ) fin. The female may carry her young on her back.
Porpoises have 60 to 120 teeth, which are flattened into a spade shaped
at the tip.
The common porpoise makes an explosive noise
as it surfaces to exhale. It has been called a "puffing pig".
Return to Wildlife Menu HERE!!