by Corinne Daniel
Gray
Whale
(Eschrictius robustus)The gray whale is a baleen whale.
The gray whale used to be known among the whalers as the devilfish due to
the fierce fight they put up to defend themselves against the hunters. A
full-grown gray whale can be up to forty-five to fifty feet long, and weigh
approximately thirty-six tons. As is common with all baleen whales, female
gray whales are typically larger than the males of this species. The coloration
of the gray whale is usually gray with white, blotchy spots. The gray whale
is equipped with two to four throat grooves, which are each about five feet
long. The purpose of these throat grooves is to enable the throat to expand
in preparation of the huge intakes of water necessary in filter feeding.
Although lacking a dorsal fin, the gray whale does have two broad flippers
and a series of little ridges are stationed along its back near the flukes
(tail).Gray whales are bottom feeders.
They typically feed on their right side and they eat by sucking up mouthfuls
of mud and their baleen filters pick out the food and they spit the rest
of the mud back into the water. Gray whales eat mostly small crustaceans,
plankton and mollusks. The gray whale eats very little during certain times
of the year including the duration of migrations and while in the warm breeding
waters (about 3-5 months). The gray whale can have up to a 10-inch layer
of blubber during these times they are forced to live off this fat.The estimated worldwide population
of gray whales is about 15,000 – 20,000. Gray whales usually congregate
in small pods of about three whales, but these pods can have as many as
sixteen members. In feeding waters larger groups (up to hundreds of whales)
are formed, these are temporary bonds and they do not establish long-term
relationships. Gray whales may communicate with each other with sounds but
we cannot be sure. For instance, noises such as forceful spouts might signal
aggravation or slapping pectoral flippers of flukes may indicate arousal,
excitement, or aggression.As their surroundings require,
gray whales are very agile swimmers. Gray whales have the ability to dive
for up to 30 minutes and can safely go 500 feet deep. They also breach,
which is when they jump out of the water a little bit and re-enter at an
angle. When they do this they make huge splashes and loud noise. It is possibly
a means of communicating with other whales as well. Also gray whales also
do something called “spyhopping”. When spyhopping the whale pokes its head
up to 10 feet out top the water, and has a look around by turning slowly.
Although the gray whale does live underwater it has to breathe air by coming
up to the surface of the water and breathing through two blowholes near
the top of the head. When they are at rest, the gray whale breathes about
2-3 times a minute, but when they are diving they can go for 3-5 minutes
with out coming to the surface to breathe.The most common habitat for
gray whales is the surface of the ocean near the coastline, but they dive
to the bottom for food. Gray whales migrate approximately 12,500 miles each
year, beginning in the Arctic Ocean (northwest of Alaska in the Chukchi
Sea), and ending off of the Baja Peninsula of Mexico. Throughout the whole
journey the gray whales stay near the coast. The whales feed in the cold
water and in the warmer water calving and mating take place.Mature females give birth every
other year in the warm water off of the Baja Peninsula. Ten seconds after
its birth the calf instinctively swims to the surface (with much help from
its mother) for its first breath. After as long as 30 minutes the baby whale
can swim without assistance. A newborn gray whale is usually about 15 feet
long and weighs about 1-1.5 ton, but like with humans, this can vary. Twins
are extremely rare and only one out of every hundred births is twins. A
calf can consume up to 50-80 pounds of its mother’s fatty milk per day,
and is weaned at the age of 7-8 months after its birth. Gray whales reach
maturity at 8 years and the growth stops when the whale is 40. Gray whales
typically live to be between 50 and 60 years old.The biggest predators of gray
whales are killer whales. The gray whales are much larger than the killer
whales and the killer whales have to team up to take down a full-grown gray
whale. Large sharks may prey on gray whales but they tend to target the
gray whales that are injured, ill or young. The small cookie cutter sharks,
which are only about 38cm, are also threats to the lives of gray whales.
Using suction, they attach themselves to the whales, and then they carve
out a core of flesh with their large triangular teeth. Humans are also dangerous
to gray whales.The gray whale has many parasites,
and their bodies are covered with hundreds of pounds of barnacles and whale
lice. Interestingly enough, little or no parasites are found on the right
side of the whales because of the way that it rubs against the ocean floor
while feeding. Skin parasites attach themselves to the head area, back,
and blowhole area also.I have really enjoyed learning
more about the gray whale, I think that they are stunning creatures and
I hope that this paper will inspire readers to appreciate them more fully,
as I have through doing this research.
Gray Whale
