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Biology > harbor
porpoise > fast facts
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| scientific
name |
Phocoena phocoena
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| body
size |
1.4-1.9 m, 45-60 kg
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| average
life expectancy |
8-12 years
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| vocal
behavior |
Make a variety of sounds, some within our hearing range
and others, which are too high a frequency for humans to
hear.
Use slow repeated echolocation clicks for navigation and
rapid bursts of echolocation to focus in on prey or other
items of interest.
Have also been reported to use whistles, which may have
social or communication significance.
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| physical
characteristics |
Have a counter-colouration scheme of gray - brown dorsal
pigmentation, with lighter lateral undersides, which become
white to grayish-white on the most ventral surface.
There are often gray stripes or flecks within the white
pigmentation.
A distinctive lateral grey - brown stripe extends from
the corner of the mouth to the anterior insertion of the
pectoral flipper on both sides of the animal. The width
and pigmentation of this stripe varies among individuals,
however is rarely visible on wild, healthy animals.
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| behavior |
Harbour
porpoise surface with a gentle rolling motion and infrequently
breach or display at the surface, although when feeding in
tide lines, they will often fast-surface creating a low splash.
Unlike Dall's porpoise, harbor porpoise rarely approach vessels
that are underway, however, the harbour porpoise of southern
British Columbia have been observed to occasionally exhibit
vessel curiosity, especially when clustered in large aggregations.
During these aggregations, they have been observed to "surf" in
the vessels stern wake. |
| distribution |
The
harbour porpoise has a Northern Hemisphere, circumpolar distribution
and is found in the Pacific and Atlantic Oceans, and in the
Black Sea and Sea of Azov. This species inhabits the cold-temperate,
sub-arctic neritic waters of North America, the Russian Federation
and Eurasia; as well as some mid North Atlantic landmasses,
such as the Faeroe Islands, Greenland and Iceland. They are
typically found in coastal ocean waters, although they are
known to ascend rivers while pursuing prey. |
| diet |
Often overlaps with species that are commercially important
to humans.
A variety of fish, such as herring, hake, codfishes, and
also prey on small squid. Pacific cephalopod prey species
include the market squid or opal squid, also known as calamari.
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| foraging
behavior |
Harbour porpoise feed on prey both within the water column and
on the sea floor. They typically eat fish and squid between 10
- 25 centimeters in length. Like other odontocetes, they cannot
chew, so they must swallow their prey in whole pieces. It has
been proposed, that harbour porpoise may go for larger fish,
but will attack them from behind and bite through them at the
gills, ingesting the body without the head. Experiments at the
Harderwijk rehabilitation center for stranded harbour porpoise
in the Netherlands have shown that harbour porpoise actually
create negative pressure in their mouths, using their tongues,
to suck the fish into their mouths. This would reduce the likelihood
that a live fish could escape. They also manipulate fish to swallow
them headfirst. Some harbour porpoise have died by trying to
eat prey that is too large to swallow.
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| habitat |
found over the coast shelves in both the North Pacific
and North Atlantic.
are also small populations in the Black Sea-Sea of Azov.
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| reproduction |
one calf every year to every other year. 10 -11 month
gestation period.
reproduction is thought to be based on sperm competition,
rather than competition between males for females.
testes of a male harbor porpoise are exceptionally large
during the reproductive season and may account for 4% of
his body weight. This means that a 50kg male, will have
2 kg testes.
Lactation lasts for approximately 9 months but calves
will start to consume solid food at about 5 months of age.
Calves may stay with their mothers for up to another 9
months post-weaning.
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| conservation
status |
The harbor porpoise is listed as a species of Special
Concern in the Atlantic and Pacific by the Committee
on the Status of Endangered Wildlife in Canada (COSEWIC).
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Harbor Seals Fast Facts >>>
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