The gray whale's name comes
from the numerous gray patches and white mottling
on its dark skin. Most gray whales are also
marked with many scratches, scattered patches of
white barnacles, and orange whale lice. Newborn
calves are dark gray to black.
The gray whale's upper jaw is
narrow and slightly arched. It has no dorsal fin,
but does have a prominent dorsal hump about 2/3
of the way down the back, followed by 9-12 knobs.
The flippers are paddle shaped and pointed at the
tips. The fluke is 10-12 feet across, pointed at
the tips, and deeply notched in the center.
Adult males are 45-46 feet long
on average, and weigh 30-40 tons. Females are
slightly longer than males, but weigh about the
Gray whales have the coarsest
baleen of all whales, with only about 20 bristles
per inch of plate (compared to over 100 per inch
in sei whales). amd 130-180 plates on each side
of the jaw.
Gray whales live in the shallow coastal
waters of the eastern North Pacific. There used
to be a population in the western North Pacific,
but it is now extinct.
Gray whales leave their feeding
grounds in October and make their way to breeding
and calving grounds off the coast of Baja
California. The journey takes about 2-3 months,
and they will remain their for another 2-3
months. One of the longest migrations of all
mammals, the gray whales will have traveled
10,000-14,000 miles by the time they return to
their feeding grounds.
Like all other baleen whales,
the gray whale is a filter feeder. Unlike other
baleen whales, however, it feeds on the ocean
bottom, rather than straining nutrients out of
the sea directly. To feed, a gray whale dives to
the bottom, rolls on its side, and draws bottom
sediments and water into its mouth. As it closes
its mouth, water and sediments are expelled
through the baleen plates, while small
crustaceans are trapped on the inside.
A female gray whale gives birth
to one calf every other year, on average. Twins
are not unheard of, but are extremely rare. The
calf is born after a gestation period of 12-13
months. It is about 15 feet long and weighs
1,100-1,500 pounds at birth, and can swim within
30 minutes. It is weaned at 7-8 months.
Gray whales reach sexual
maturity at 5-11 years, or when they reach a
length of 36-39 feet. Average lifespan is 4-50
years in the wild.
Gray whales are not very social
animals. They generally congregate in loose pods
of 3-16 whales, but form no long-term bonds.
Although an agile swimmer, a
gray whale seldom travels faster than 2-6 mph; it
can, however, go up to 10-11 mph in bursts when
in danger. It can dive to a depth of 500 feet and
stay submerged for up to 30 minutes, and can swim
in relatively shallow water without running
genus & species Eschrichtius robustus
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