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GRAY WHALE
Eschrichtius robustus
meaning of scientific name: Eschrichtius-named after the Danish
professor who worked with these animals; robustus-strong
DESCRIPTION:
Gray whales are medium sized whales, reaching up to 45 feet
(14 m) in length, with the females usually being larger than
the males. They are gray with white patches, which mostly
consist of areas where barnacles and lice have attached themselves
to the whales. In fact, they carry over 400 pounds of barnacles
and whale lice. Gray whales have no dorsal (back) fins. Instead,
they have a low hump and a series of six to twelve knuckles
or bumps. Gray whales are baleen whales, and each has approximately
300 plates of cream-colored baleen hanging from its upper
jaw. Two to five throat creases allow their throats to expand
during feeding. Sparse hairs are found on the snout, especially
in young whales. Their blows are usually low and puffy or
heart-shaped.
RANGE/HABITAT:
Gray whales are found only in the Pacific Ocean, with a population
of approximately 26,000. The largest group of gray whales
summers north of Alaska in the Bering and Chukchi Seas and
winters in the waters of Baja California, Mexico. Another
group in the Pacific, found in the waters of Korea and Japan,
is close to extinction with only 100-250 individuals. Another
group of gray whales once lived in the North Atlantic Ocean
and became extinct in the 17th century, due to hunting. Gray
whales generally stay around the continental shelf and are
truly a coastal species.
BEHAVIOR: Gray whales have one of the longest migrations
of any mammal. During summer, they live in the Arctic in areas
rich in their food, bottom-dwelling organisms. As fall approaches,
there is less sunlight, less food, and the water turns cold.
This is when the whales travel to Baja California, where they
enter lagoons to give birth and mate. Gray whales can be seen
passing by California in December and January during their
southern migration, and again in March and April on their
northern journey.
Since gray whales migrate relatively close to shore, whalewatching
has become very popular. Many opportunities are available
for viewing gray whales from coastal cliffs and headlands
or from whalewatching boats. In the seventies, "friendly
whales" were first encountered in San Ignacio Lagoon
in Baja California, Mexico. Here, gray whales will sometimes
swim near small boats and allow themselves to be touched.
Concern has grown about the impact of boat traffic around
whales, and the number of boats allowed in the breeding lagoons
is restricted. Along the migration route, boats' proximity
to whales is also limited.
Gray whales feed by sucking in bottom-dwelling animals, mostly
amphipods (which are related to shrimp). Muddy patches of
water are often seen in places where gray whales are feeding.
They feed primarily in the Arctic, although some have been
observed feeding during the migration.
MATING AND BREEDING: Female gray whales usually give
birth every two to three years, and their pregnancies last
twelve months. Newborn calves average 16 feet (4.9 m) in length
and weigh about 1,500 pounds (680 kg). Calves are weaned at
about eight months, after they have journeyed with their mothers
back to the northern feeding grounds.
STATUS: Gray whales have returned from the brink of
extinction. In the late 1800s, the gray whale breeding grounds
were discovered, and whalers killed a large percentage of
the population. The drop in population made it no longer profitable
to hunt gray whales; they were left alone and their numbers
recovered. However, the early 1900s brought the invention
of factory ships, which processed whales aboard the vessels.
This new technology allowed intensive hunting on the grays
once again, and their population again dangerously dropped
to probably fewer than 2,000 individuals. Protection finally
came in 1946 through an international agreement to stop hunting
them. Since that time, the population has grown to over 26,000,
similar to what it was before modern-day whaling. As a result
of this population recovery, gray whales were removed from
the endangered species list in 1994.
In 1998 the International Whaling Commission reinstated a
treaty made between the U.S. Government and the Makah Indians
in 1855, giving the Native American group the permission to
hunt gray whales. Under the new agreement, the Makah are able
to take 20 whales through the year 2004. After a 70-year ban
on gray whale hunting, the Makah took their first whale in
May of 1999. The revival of the treaty is very controversial.
Since the Makah have been allowed to continue gray whale hunting
for its importance to their native culture, the environmentalists
are calling for no exceptions to the hunting ban. This is
because of the fear that the treaty revival will start a trend
toward hunting other marine mammals.
AT THE MARINE MAMMAL CENTER: The Marine Mammal Center
has never had a live gray whale as a patient, but each year
during the whales' migration, a few whales die and wash up
on the shore. When this happens, scientists from The Marine
Mammal Center and other organizations perform a necropsy (autopsy)
to determine the cause of death. Since 1997 the number of
dead gray whales washing ashore along the North Pacific coast
has gradually increased, with 269 reported along North America
and Mexico in 1999. In 2000, more dead gray whales washed
ashore near the San Francisco Bay than had in previous years.
Necropsies were performed on those that were accessible and
in good enough condition, but no one factor was linked to
the cause of these deaths. In 2001, only 13 gray whale deaths
were reported. However, scientists from The Marine Mammal
Center and other concerned organizations are continuing to
investigate the deaths of the previous two years.
May be reprinted for scientific and educational purposes
Revised 1/02
Learn more about the following:
Humpback
Whale
Blue Whale
Orca/Killer
Whale
Beluga Whale
Dolphins
and Porpoises
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Gray
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