Description
& Characteristics:
One
of the worlds most abundant large mammals, Crabeater
seals' numbers have increased enormously in the last
50 years most likely due to declining whale populations.
Inhabiting the shifting pack ice which surrounds the
Antarctic continent, comparatively little is known about
their behavior due to the difficulty of establishing
scientific field stations on the ice.
Crabeaters
are mostly dark grey in appearance, but in summer the
coat can bleach almost to white. In general, they are
lighter on the bottom (their ventral side) and darker
on the top (their dorsal side). Their faces are dog-like
and they have characteristic chocolate-brown markings
and fleckings on the shoulders, sides and flanks.
Crabeaters are misnamed, since they actually eat krill,
not crabs, occasionally supplementing their diet with
small fish and squid. Pursuing prey on shallow dives,
they use rows of interlocking upper and lower teeth
to form a sieve-like palate which strains krill from
the water. They can consume 20-25 times their body weight
in a year. In fact, the total amount of krill consumed
by Crabeater seals is more than that of all the remaining
baleen whales put
together.
Crabeater
seals are more agile on land and ice than other Antarctic
seals and thus can travel far from the open sea. The
remains of dead seals, presumably trapped by pack ice,
have been found miles from the sea.
During
breeding season, Crabeaters are generally observed occurring
in small family groups as opposed to the teeming breeding
beaches of gregarious Fur
seals. Not much is known about crabeaters' breeding,
which occurs among the pack ice during the austral spring.
Like Southern
Elephant seal pups, Crabeater pups grow very quickly
and are weaned within two to three weeks having gained
up to 200 pounds in weight. During this period, the
male patrols a sizeable territory (up to a 150 foot
radius) around his mate and pup, aggressively fending
off unwelcome intruders. Skirmishes are frequent with
even the females becoming combative during this time.
There is some evidence that Crabeaters may be monogamous,
although this is rare in seals. After weaning, young
Crabeater seals disperse to open waters to feed independently.
The
Leopard seal
is the main predator of young Crabeater seals and an
important one in helping to keep populations in check.