Common Name: Harbor Seal
Harbor Seal Taxonomy/Description
seals belong to the Mammalian Order Pinnipedia, in the family
Phocidae. Other members of Phocidae include elephant seals, gray
seals, and monk seals. Phocids are referred to as true seals. They
are distinguished from other pinnipeds by their inability to support
their body using their hind limbs. The harbor seal's scientific
name, Phoca vitulina, means "calf-like seal".
seals are easily
identified by the spotted coloring on their fur and their dog-like
faces. There are five subspecies of harbor seal, separated
geographically. They have short thick fur, can grow to be up to
6.5ft in length, weighing up to 375lbs. The average lifespan for a
harbor seal is 25-30 years. Coloration and patterns vary from
individual to individual from a dark background with light rings to
light colored sides and belly with dark blotches or spots.
Harbor Seal Habitat/Diet
seals are found all along both coasts of North America. They live
along the shores in the north Atlantic and Pacific oceans. On the
Pacific they range from Alaska to Mexico. Northern European coasts
and northern Canadian and American coasts They tend to occupy the
shallow waters along shorelines and do not characteristically move
very far out into sea. Harbor seals are occasionally found in
rivers and lakes.
seals eat squid, clams, octopus, fish and crustaceans. They do not
chew their food, instead tearing it to chunks and swallowing it
whole. They are hunted by killer whales, polar bears, sharks,
Steller's sea lions, walruses, eagles, coyotes, and humans.
Harbor Seal Behavior/Reproduction
seals live in small groups but are hunt alone. Harbor seals dive to
depths of 400ft for time periods of 20 minutes when hunting. They
do not make long migrations. Winter and summer movements are not
very clear, but more information is becoming available as
researchers tag and study current populations. Newborn pups are
able to swim almost immediately after birth. Sexual maturity is at
3-7 years. Females mate soon after delivery. Delayed implantation
causes the egg to implant 11 weeks later.
seals and other true seals swim by powerful sideways movements of
their hindquarters. Their short front flippers are used mainly for
steering through the water and for grooming themselves. Their
broadly webbed flippers are less useful on land and cannot support
their weight. The movement of a harbor seal scooting along on its
belly on land is similar to the movements of an inchworm.
seals spend half their time in the sea. They tend to spend part of
each day hauled out on land where they warm themselves in the sun.
Harbor seals haul out onto to land to rest, dry out, regulate their
body temperature, give birth, nurse their pups, and molt. They arch
their bodies so that the maximum amount of their skin is exposed to
the drying effects of the air.
Harbor Seal Conservation
number of Harbor Seals that inhabit the Pacific coast of North
America has greatly declined in recent decades. Pollutants and
human waste collect near the shore where harbor seals live. Thus,
the overall threat to these animals derives from the ever growing
human population. As more and more people inhabit the earth, they
occupy more coastal areas and deprive these seals from shorelines
that they have inhabited for millions of years. Still this species
is not critically endangered and there is plenty of reason to hope.
While on the Pacific coast, we were lucky enough to study the major
haul-out site of the largest remaining population of breeding harbor
seals. This was at Limantour Beach in Point Reyes National Sea
a big conflict between seals and commercial fisheries. The seals
damage the nets, and other fishing gear often harms seals. Another
big threat to seals is water pollution. The presence of domesticate
dogs on beaches transmits canine distemper to seals. Humans also
cause problems by "helping" seal pups that are “stranded”. The
mothers of such pups are actually out hunting. Although motivation
to help Marine Mammals is a positive, ignorance of Marine Mammal
behavior is very negative, and everyone should strive to expand
their knowledge and understanding of Marine Mammal conservation.