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The gray whale is a species of large baleen whale,
also known by the scientific name of Eschrichtius
robustus. It is the only member of the taxonomic genus
eschrichtius as well as the family eschrichtiidae.
The gray whale can be found in the north of the Pacific
Ocean, where two gray whale populations exist. One
population resides in the west of the ocean, near
southern Korea, and is considered critically endangered
with a total of only 130 individuals. The other population
can be found in the east of the Pacific, between Alaska
and the Mexican state of Baja California Sur, and
is much larger, containing over 20,000 individuals.
As its name suggests, the gray whale is dark gray
in color, and has distinct white and gray markings
across its skin caused by parasites that attach to
the whale but drop from its skin in cold, deep waters.
It is also distinguished by its two blow holes and
its off-white, atypically short baleen.
On average, the gray whale measures between 43 and
49 feet in length and weighs 15 to 33 tonnes. At its
largest, the gray whale can weigh up to 40 tonnes,
over 88,000 pounds. Females are typically larger than
males.
As a baleen whale, the gray whale is a filter-feeder.
It subsists primarily on crustaceans found in the
deepest layer of the ocean, where it feeds by turning
its head to one side and filling its mouth with sediment.
Its baleen subsequently filters this mixture, capturing
small sea life for the whale to consume. The gray
whale does most of its feeding in the north during
the summer, and feeds only opportunistically while
it migrates, relying predominantly on stores of fat
during its migration.
The gray whale migrates yearly starting in October,
when ice from the north begins to move south. During
its migration, the gray whale travels an average of
75 miles per day, traveling both day and night at
an average speed of five miles per hour. The gray
whale's migration covers distances of 9,900 to 13,700
miles round trip, making it perhaps the longest migration
of any animal.
This migration also serves as a trek to the gray
whale's breeding areas. Most gray whales arrive at
their destination by mid-February to mid-March, seeking
lagoons in which to give birth and search for mates.
The first gray whales to begin the trip back, generally
gray whales without newborn calves, depart in February
and March. Nursing or still-pregnant females tend
to remain at the breeding area until their calves
are ready for the trek back, typically leaving in
March or April but sometimes staying as late as May.
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