sea otter is the smallest marine mammal on the coast of
British Columbia . Males can weigh up to 45 kilograms and
reach 148 centimeters in length. Females are slightly smaller.
Sea otters have the thickest fur of any living animal: 100,000
or more hairs per square centimeter or about 1,000,000 hairs
per square inch. Unlike whales and seals, who rely on their
thick layers of blubber to insulate themselves in cold waters,
the blubberless sea otters rely only on their fur for insulation.
To maintain body warmth, sea otters feed constantly, and
continually groom their fur; clean fur allows air to be
trapped and warmed between the strands, and prevents water
from touching the animals' skin. Soiled and clumped fur,
in contrast, leads to a loss of insulation and threatens
the sea otter with hypothermia.
Female sea otters begin to have pups when they are between
3 and 5 years of age. Males do not breed until they are
at least 5 or 6 years old. Females generally bear one pup
a year, with most births occurring in the spring. Pups remain
with their mothers for at least the first 6 to 8 months
of life. Sea otter females, on average, live from 15 to
20 years, and male sea otters live from 10 to 15 years.
Sea otters live in unpolluted nearshore marine environments,
usually in depths under 40 meters. On the west coast of
Vancouver Island, sea otters have been observed to frequent
different habitats in different seasons more sheltered waters
during winter storms, for example. They are social animals,
congregating in single-sex (all males or all females) groups
called rafts. Rafts of sea otters can contain hundreds of
animals. Males and females tend to occupy different territories.
Males generally expand into new areas first, while females
use areas that sea otters have occupied for longer periods
of time and expand into areas vacated by male groups. In
Alaska, male sea otters have been known to travel as much
as 100 km. a day. The sea otter has only a few natural predators
besides man. Bald eagles are known to prey on pups, and
killer whales eat sea otters, usually when other preferred
foods are not available.