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Gray Whales
Common Name: Gray Whales
Scientific Name: Eschrichtius Robustus
Description
 Gray
Whales (Eschrichtius robustus) are baleen whales. Adult gray
whale length is 39-46 feet, with the largest recorded measuring
a little longer than 49 feet. Weight is 15-39 tons. A gray
whale can live approximately 70 years.
Gray
whales are divided into two discrete populations, one on either
side of the North Pacific Ocean. The eastern population migrates
along the West Coast of North America between winter calving
grounds along Baja California, Mexico, and summer feeding
grounds in the Bering and Chukchi Seas between Alaska and
Russia. The eastern population has made perhaps the most complete
recovery of any large whale population depleted by commercial
whaling. The annual migration of some gray whales back and
forth between calving and breeding grounds can exceed 10,000
miles, making it the longest annual migration of any mammal.
The western population occurs along the Asian coast, where
it migrates between summer feeding grounds off Sakhalin Island,
Russia (about 500 miles north of the Japanese island of Hokkaido),
and winter calving grounds at an unknown location suspected
to be in the South China Sea. In contrast to the eastern population
it remains one of the most critically endangered populations
of any large whale numbers perhaps by 100 animals.
Diet
Gray
whales feed in shallow waters, usually 150-400 feet deep.
Adults can consume 1-1½ tons of food per day during peak feeding
periods.
Physical Characteristics
| |
At Birth: |
At Maturity: |
| Length |
4.9 m (16') |
Up to 15 m (49') |
| Weight |
680 kg
(1,500 lb) |
Up to 35,000 kg
(80,000 lb) |
| Age |
Known to exceed 40 years |
| Range and Habitat |
Shallow Coastal Waters |
Behaviour
The
gray whale is unique among cetaceans as a
bottom-feeder that rolls onto its side, sucking up sediment
from the seabed. Bottom-dwelling organisms live in this sediment,
and stay in the baleen as water and silt are filtered out.
The Blow or Spout:
A gray whale's blow is up to 15 feet high,
and each blow is visible for about 5 seconds. When warm, moist
air exhaled from the animals' lungs, meets the cool air at
the ocean surface, it creates the bushy column we call a blow,
or spout. Anticipate that the whale will dive for 3 to 6 minutes,
then surface for 3 to 5 blows in row, 30 to 50 seconds apart,
before diving deep for 3 to 6 minutes again.
The Flukes (Tail):
Before making a long, deep dive, a gray whale often displays
its 12 foot wide fan shaped flukes, or tail. The weight of
the tail above the whale's body helps the whale to dive deep.
The gray whale normally swims about 5 miles
per hour about the speed of a child on a bicycle. The flukes
have no bones and connect to the body and tail muscles by
banks of tendons.
Breach and Splash
Gray whales occasionally
hurl themselves out of the water and plunge back in with a
tremendous splash! This is called a whale breach. Scientist
do not know why gray whales do this, but it is very exciting
sight to see! Sometimes other whales in the area will copy
this behavior, so keep your eyes open
Life History
Gray
whales spend April-November in their Arctic feeding grounds,
and December-April in Mexican breeding areas. Between October
and February the species migrates south along the West Coast,
returning north between February and July. This round trip
migration of 7,400-12,400 miles every year is believed to
be the longest of any mammal.
Location or Region Found
 This
species is a coastal cetacean, usually seen over the continental
shelf. During migration most animals pass within about a mile
of the shoreline, and gray whales occasionally come into Puget
Sound.
When to See Whales:
Mid January is the
peak of the migration, but the Grays are visible mid-December
through March. The heights around the park's Whale Overlook
and Old Point Loma Lighthouse offer the best viewing. Bring
binoculars if you have them. Binoculars make viewing much
easier and more enjoyable. It is possible to see a whale at
any time of the day (they swim 24 hours a day)! Park staff
will happily help you spot a whale if possible. Check at the
visitor center for information about ranger talks and whale
watching. A movie about the Pacific Gray Whale is shown daily
during the Whale Watch season.
Where to Look:
Look west from the
park overlooks, toward the ocean. The whales are migrating
from the arctic to the warm bays of Baja California and mainland
Mexico, so they will be moving from the north (right), to
the south (left) as you look from the park. Expect them to
be moving at a steady speed of four or five knots (about five
miles per hour). Although some swim close to shore, most whales
swim in an area that extends from the kelp beds (about 3/4
miles out) out to the horizon. Binoculars are an immense help,
so bring a pair if possible. A limited number of binoculars
are available with a picture i.d. at the park visitor center
during the whale season; ask for them at the information desk.
Note:
Later,
in the spring, the gray whales will migrate north again, but
they are generally too far out in the ocean to see from the
park, even with binoculars.
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