Biology
Pinnipeds - what are they?
Pinnipeds are marine mammals. The ancestors of pinnipeds (Pinnipedia) were land-living carnivores (Order: Carnivora) and through evolution they have adapted to life in the water. Some of the adapted characteristic features include the streamlined body shape, limbs which are modified as flippers, a thick layer of blubber, which helps them conserve body heat, and the ability to close ears and nose when they are in water.
Pinnipedes feed on a large variety of prey species. They mostly feed on fish, but also crab, squid, mussels, sea birds and seal pups are found to be part of their diet.
The clade Pinnipedia is divided into 3 families:
|
True seals (Latin: Phocidae, 19 species) |
Eared seals (Latin: Otariidae, 15 species) |
Walruses (Latin: Odobenidae, 1 species) |
 |
 |
 |
Harbour and grey seals belong to the family of true seals. This group of pinnipeds is characterised by the absence of external ear flaps (pinnae), instead they have small openings on both sides of their head. True seals have short front and hind-flippers, and because of the position of the pelvis are unable to turn them forward. Therefore movement on land is accomplished by undulation of the body which often makes the true seals appear clumsy. In the water however true seals are agile and elegant swimmers.
Overview native seals
|
Grey seal (Halichoerus grypus)
|
|
Common seal (Phoca vitulina vitulina) |
|
Temperate to subarctic waters in the northern hemisphere
|
Distribution |
Temperate to subarctic waters in the northern hemisphere |
|
Three populations (Baltic, western Atlantic and eastern Atlantic population) |
|
Five subspecies ( western Atlantic and eastern Atlantic population , western Pacific and eastern Pacific population, Ungava seal)
|
|
Males: dark brown coat, sometimes nearly black, with few light patches Females: light grey coat with dark spots and patches
|
Appearance |
Unique speckled or spotted pelage (background colour pale grey or brown) with light or dark rings |
|
Long „roman“ nose |
|
Rounded head
|
|
Broad, elongated body
|
|
Rounded, fusiform body |
|
Back teeth cone shaped
|
|
Back teeth forked |
|
♀ 190-200 cm ♂ 230 cm
|
Length |
♀ 150 cm ♂ 170-180 cm |
|
♀ 105-186 kg ♂ 170-310 kg
|
Weight |
♀ 80 kg ♂ 120 kg |
|
Up to 40 years
|
Life span |
Up to 40 years |
|
♀ 3-5 years
|
Sexual maturity
|
♀ 3-4 years |
|
♂ 5-7 years, first successful mating 8-10 years
|
|
♂ 5-6 years |
|
fish, cephalopods, crustaceans, sometimes seabirds |
Food / Diet
|
fish, cephalopods, crustaceans |
|
11 months, including 3 months dormancy |
Gestation period
|
11 months, including 3 months dormancy |
|
Winter: november- january (German Bight) |
Birth period
|
Summer: june - july |
|
Baltic: March- April
|
|
|
|
2-3 weeks
|
Weaning |
4-6 weeks |
|
After weaning, in Schleswig-Holstein January - February
|
Mating
|
After weaning, july and august |
|
On land and in water
|
|
In water
|
|
~ 450.000 individuals worldwide
|
Population
|
~ 500.000 individuals worldwide
|
|
~ 4.050 individuals in the Wadden Sea |
|
~ 38.500 individuals in the Wadden Sea
|
|
~ 625 in Schleswig-Holstein & on Helgoland |
|
Ca. 10.000 im schleswig-holsteinischen Wattenmeer |
