to The Gray Whale Page!
A student web page designed by Robin Dale
Gray whales are relatively large, twice the length of a killer whale,
and half the length of a blue whale. Adult gray whales are 10-13m (35-45ft),
with an average length of 11m (39ft). They weigh 22-38 tonnes (20-35
tons). Females whales are usually larger than male whales. The record
whale was 15.5m (51ft) and 42 tonnes (39tons).
whales have a long and narrow shape and are a medium gray
colour marbled with lighter patches. At the water surface
they appear to be a whitsh-blue colour. Each whale has
its own unique skin pattern which allows for identification.
Their skin is smooth, and feels like a hard-boiled egg
without the shell. Their head is quite long - one fifth
the total body length - and it arches downward. The eyes
of gray whales are brown and about the size of on orange.
The snout and jaw have many short coarse bristles, 50 on
top and 100 on the bottom. They steer themselves with their
pectoral fins and power themselves with their tail. The
tail can measure 3m (9ft) across and can weigh up to 180kg
to be classified as giant fish, even today whales are
often administered by fisheries departments instead
of wildlife departments. In 1693 John Ray classified
whales as mammals, and centuries later (1864) Gray
Whales were given the scientific name Eschrichitus
robustus. Theyre classified in the order Cetacea,
which comes from the Greek work ketos, which means
sea monster. Gray whales are a type of baleen whale,
and has its own family which is Eschrichtiidae. They
have many nicknames, including California whale, desert
whale, devilfish, hardhead, and clam digger.
In the winter the whales live down in California and
they migrate up to Alaska for the summer. They start
to head down to California in early
October, making their migration one of the longest of all animals. They
end up in lagoons on the west coast of Baja California. Travelling through
day and night, they cover about 125km (82miles) each day. They take 6-7
rests per day, each of which is about a half hour long. By December the
Grays reach Baja where mating takes place, females impregnated the previous
year give birth. After winter is over they start to head north for the
summer. They migrate in groups of 1-5, and occasionally in groups up
to 18. The mature whales leave first, followed by juveniles. Mothers
with their calves are the last to leave which is about March. A few can
still be found in May though. Their trek back up north isnt as
fast as on the way down because their isnt the need for the females
to give birth.
of the whales end up staying off the coasts of California,
Oregon, Washington, and British Columbia. The largest group
of summer residents are usually found off Vancouver Island,
where 30-50 grays stop to spend the summer. Many of them
have been given names which relate to their appearance.
For example, Two Dot Star has two white patches on his
back, and Prop has scars form a boat propeller.
Hearing is the most important sense for whales. In water, sound travels
four times as fast as in does in air and it also travels further. Some
of the sounds whales make can be heard above water. Fishermen used to
think that their moans and whistles were sea monsters or mermaids. They
vocalize using clicks, groans, grunts, squeaks, rasps, and roars. These
sounds are produced by squeezing air through the blowhole, or by bursts
of air from the lungs.
Since their eyes are far back on their head, gray whale vision
consists on two fields on either sides of the body, rather
than the binocular
view that humans have. There is some uncertainty about how well whales
can see because their eyes are very small, although they seem to have
good eyesight in both water and air. Its unknown whether whales
can see colours or not.
A whale researcher, Rod Palm, once saw a young gray whale in shallow
water close to a beach. When he walked down the beach, the whale followed
along in the water. When he changed direction, so did the whale. Then
the whale pushed itself onto the beach and looked at Palm, then went
back into the water.
Gray whales are mostly bottom feeders. They swim to the bottom of the
ocean, roll onto their side, and stick their head a few inches into the
bottom. They expand and contract their throat grooves, and retract their
tongue (which may weigh 1300kg!), which creates suction that brings mud
into its mouth. The mud is moved around a little and pushed out through
the baleen.. The food gets trapped by the baleen and the rest is pushed
out the sides of the mouth.
In some areas you can walk out at low tide and see huge pits in the bottom
mud which are up to 3m (10ft) long. The food they get from the bottom
includes amphipods, isopods, gastropods, bivalve molluscs, worms, and
hydrozoans. As much as 90% of it is amphipods. The whales also feed on
floating and swimming organisms. This includes shrimp, herring roe, tube
dwelling worms, plankton, squid, small fish, crab larvae, shoals of red
crabs, small crustaceans, and sometimes kelp. Most likely they eat kelp
to help ease intestinal upsets, or stomach aches, just like a dog eats
grass. On average they eat a ton of food a day.
Predators and Diseases
A natural predator of gray whales is the orca, or killer whale. The transient orcas eat young gray whale calves. Gray Whales are also bothered by small parasites and barnacles. "Whale lice" are often found crawling among the barnacles, which feed on dead skin.
These are so common that the adult gray whale carries several
hundred pounds worth of them. They can remove the parasites
by rubbing on gravel on the ocean bottom, or entering coastal
lagoons and the mouths or rivers (fresh water kills their
get cancers, stomach ulcers, heart disease, pneumonia,
jaundice, and arthritis. Sometimes whales are found
stranded on beaches, possibly from illness, wave action,
currents, or parasitic infestations/diseases which
affect the whales ability to navigate.
been hunted by humans for hundreds or years. In 1854
hunts began taking gray whales of the lower coast of
California. The hunt didnt boom until 1858, at
which time began a rapid decline of gray whales in
North America. In 1969 the United States added 8 species
of whales to the Endangered Species Act, one of these
was the California gray whale. This helped to shut
down whaling businesses, from lack of demand from people
for whale products. The gray whale population started
to recover slowly. In 1994 gray whales were removed
form the endangered list The only gray whales legally
taken today are by aboriginals in Alaska and the Russian
Republic. In October 1994, the IWC gave Washington
States Makah Native tribe permission to kill
4 gray whales each year. Conservationists have threatened
to file a law suit to stop the hunt, saying that the
proposed use of high-powered rifles hardly qualifies
as a traditional native hunting method.
click here for recent news on gray whale population estimates
whales may also be dying from waste and chemicals dumped
into the oceans. Businesses and cities dump sewage, garbage,
chemicals, nuclear waste and more into the oceans, perhaps
thinking that it will go away. But it is destroying oceans
and the creatures living in them. The city of Vancouver
alone dumps over 756 million litres of sewage into the
ocean every day.
If the waste
doesnt affect the whales right away, it may get
to them when they eat smaller fish and organisms which
carry toxins in them. Fish nets are another hazard
that may trap whales, holding them under the surface
so that they cant breathe.
is another problem - whales use sound primarily to
observe their world. Gray whales may be quite effected
by the continual sound of the heavy boat traffic that
exists on their migratory routes.
Marine Mammal Center - gray whale page
Vancouver Aquarium Aquafacts
Gray Whale Migration
and answers about baleen whales
to marine biodiversity index