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| Reproduction |
Pinnipeds often come ashore or haul
out on ice to breed, often travelling
long distances from their feeding
grounds to suitable mating grounds
with a high level of reproductive
synchrony. Almost all pinnipeds are
polygynous, i.e. males breed with
up to several dozen females in a season.
Males of many species, (e.g. elephant
seals and Northern fur seals) aggressively
defend groups of specific females,
referred to as harems. Males of other
species (e.g. most sea lions) defend
territories on reproductive rookeries
while females move freely between
them. Some form of competition, either
for females or territories, some of
which can be violent, is an integral
part of the male breeding strategy
among most pinnipeds. Otariids, which
are generally more land-adapted, tend
to form major aggregations in the
summer months on beaches or rocky
outcrops. Consequently, their reproductive
behavior is easier to observe and
well studied. Walruses and many phocids,
on the other hand, tend to form smaller
aggregations, often in remote locations
or on ice, and copulate in the water.
Their reproductive behavior is therefore
generally less well known.
Females have a postpartum
oestrus allowing them to mate soon
after giving birth. Subsequent implantation
of the embryo is delayed (embryonic
diapause) thus removing the need to
come ashore (haul-out) twice, once
to give birth and again later to mate.
After giving birth mothers suckle
their young for a variable length
of time. Amongst the phocids, lactation
varies from 4 to 50 days, whereas
the otarids may lactate from 4 to
36 months. This reflects the fact
that phocid feeding grounds tend to
be a long way off-shore so lactation
is associated with maternal fasting.
To compensate for the short lactation
period, the fat content of phocid
milk is higher than in any other species
of marine mammal (45 – 60% fat).
After lactation most female phocids
make extensive migratory movements
to feeding grounds for intensive foraging
to recoup depleted energy reserves.
On the other hand, otarid feeding
grounds are generally closer to shore
and females go on foraging trips to
maintain lactation. Fat content of
otarid milk is lower than that of
the phocids owing to the protracted
lactatory period (typically 25 –
50%). Protracted nursing also leads
to the formation of social bonds
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| Photo Gallery |
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| Types of Seal |
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Pinniped
marine mammals belonging to the biological
suborder Pinnipedia
Earless
seal (or true seals), members of the
family Phocidae
Leopard
seal also members of the family Phocidae
Eared seal (walking
seals), members of the family Otariidae, which
includes:
»
Fur seal, subfamily Arctocephalinae.
» Sea
Lion subfamily Otariinae
Seal
hunting both personal and commercial
hunting of seals
Seal
brown is a rich dark brown color |
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| Where to Find Them Besides the Ocean and Sea |
You can find seals at Atlantis Marine World in Riverhead, Long Island. Another place that you can see seals is Mystic Aquarium. To see a type of seal called the Harbor Seal go to the Montery Bay Aquarium. At the New England Aquarium there are seals like Henry and Sarah who kiss. At the New York Aquarium there is a harbor seal named Herbie. |
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