The Gray Whale (Eschrichtius robustus), more recently called the Eastern Pacific Gray Whale, is a whale that travels between feeding and breeding grounds yearly. It reaches a length of about 52 ft (16 meters), can reach a weight of 36 tons and age of 50″“60 years. Gray Whales were once called devil fish because of their fighting behavior when they are hunted. The Gray Whale is the sole species in the genus Eschrichtius. This animal is one of the oldest species of mammals, having been on Earth for about 30 million years.
Population, distribution and migration
There are two Pacific Ocean populations of Gray Whales that exist: one small population traveling between the Sea of Okhotsk and southern Korea, and a larger one traveling between the waters off Alaska and the Baja California. A third, North Atlantic, population was hunted to extinction 300 years ago.
In the fall, the California Gray Whale starts a 2″“3 month, 8,000″“11,000 km trip south along the west coast of the United States and Mexico. The animals travel in small groups. The destinations of the whales are the coastal waters of Baja California and the southern Sea of Cortez, where they breed and their young are born. The breeding behavior is complex and often involves three or more animals. The gestation period is about one year, and females have calves every other year. The calf is born tail first and measures about 4 meters in length.
The whale feeds mainly on benthic crustaceans (hey include various familiar animals, such as lobsters, crabs, shrimp and barnacles) which it eats by turning on its side (usually the right) and scooping up the sediments from the sea floor. It is classified as a baleen whale and has a baleen, or whalebone, which acts like a sieve to capture amphipods taken in along with sand, water and other material. Mostly, the animal feeds in the northern waters during the summer; and opportunistically feeds during its migration trip, depending primarily on its extensive fat reserves.
Gray Whales are covered by characteristic gray-white patterns, scars left by parasites which drop off in the cold feeding grounds.