Gray Whales

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Gray whales are baleen whales that live in groups, or "pods". Whalers used to call them "devilfish" because of the fierce way they themselves when hunted. They live at the of the ocean near the coastline but dive to the bottom to . They feed in the cold Arctic Ocean (northwest of Alaska) but about 10,000 kms every year to mate and in the warm tropical lagoons of the Pacific Ocean off Baja, Mexico.

Gray whales, as their name suggests, usually have gray but they also have some blotchy white and are covered with barnacles and whale lice. They have two broad flippers but no dorsal . There is a series of small ridges along their back near the flukes (tail). Gray whales have a layer of blubber (fat) up to 25 cm . They have hairy bristles on their snout and the front of their head. These are used as tactile sensors, like a cat's whiskers. Adult gray whales are around 13-15 metres long and about 33 tonnes. Like all baleen whales, female grays are larger than .

Gray whales (like all baleen whales) are seasonal feeders and carnivores. They are bottom feeders, which means that they sieve through the mud on the ocean with their baleen. They eat krill, copepods, plankton and molluscs such as squid. They usually feed on their right side, sucking up mouthfuls of mud and then using their baleen plates to the food from the mud. During migration and while in their warm breeding waters (about 3-5 months), gray whales eat very little. They live off their thick layer of .

Gray whales are very agile . They can dive for up to 30 minutes and go 155 metres . They can swim in quite shallow water without running aground. They also "breach", jumping partially out of the water and falling back at an angle, splashing and making a loud noise. This may help clean off some of their parasites (barnacles and whale lice) or in with other gray whales. "Spy-hopping" is another gray whale activity in which the whale pokes its head up to 3 metres out of the water, turning around slowly to take a look around.

Gray whales air at the surface of the water through two blowholes located near the top of their head. At rest, gray whales spout (breathe) 2-3 times per minute. Between deep dives they take deep breaths for about 3-5 minutes. The spout of the gray whale is a noisy stream that rises 3-4 metres above the water. It can be nearly a kilometre away.

Gray whales have a expectancy of 50-60 years. Killer whales (orcas) , large sharks and humans are their only natural . It is estimated that there are about 15,000-22,000 gray whales worldwide. They are a protected .


[Adapted from a text at URL: http://www.zoomdinosaurs.com/subjects/whales/ 18th Feb. 2001]