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What Do You Know About Gray Whales?

Gray Whale

By José Eugenio Gómez Rodríguez - Own work, CC BY 3.0,

Gray whales were formerly widespread across the Northern Hemisphere, but today they can only be in the North Pacific Ocean, where two populations exist, one in the eastern and the other in the western North Pacific.

Because of their violent responses when harpooned, gray whales have acquired the moniker "devil fish." Both Pacific populations were almost wiped off by commercial whaling. In the 1930s and 1940s, international mitigation actions were established to preserve whales from over-exploitation, and that in the mid-1980s, the International Whaling Commission imposed a commercial whaling ban.

1. Baleen

The whale forages by dislodging small animals from the seabed using its nose. The baleen, the comb-like strainer of plates throughout the upper jaw, then filters these morsels. Gray whale baleen, commonly known as whalebone, is approximately 18 inches long and has a fingernail substance. Whalebone was formerly used to create corsets for women and umbrella ribs for umbrellas.

2. Migration

The gray whale is among the world's most migratory animals. A few of these giants travel 12,430 miles round-trip through their summer habitat in Alaskan seas to the warmer waters off the Mexican coast, traveling in pods. Whales spend their winters and breeding seasons in the shallower southern waters and warmer temperatures. Gray whales may also be seen in the waters around Korea.

3. Conservation

Gray whales, like other whales, have the surface to breathe. Thus, migratory groups may be seen from the west coast of North America. These whales were formerly heavily hunted, and by the early twentieth century, they were in grave danger of extinction. Gray whales have now been protected by law, so their population has increased. The gray whale was withdrawn from the endangered species list in the United States in 1994.

4. Feeding

Gray whales eat a range of tiny crustaceans, such as larval crabs & mysid shrimps, among other things. They have been seen eating tiny clams in deep muddy bays and fish larvae throughout the water column, but amphipods, little flea-like crustaceans, are their most frequent food. Gray whales may suction and skim feed at the surface or in mid-water, but they prefer to feed on the bottom, where they can find tube-dwelling or burrowing amphipods. Where gray whales have been eating, they may leave dug tracks or furrows throughout the mud. A gray whale may consume up to 1,200 kg of foodstuff per day1. Surprisingly, almost 90% of whales equipped with tags that tracked their driving behavior and position underwater preferred to roll onto their right sides when feeding.

5. Reproduction and growth

Gray whales have an indiscriminate mating system, which allows both sexes to mate with many partners throughout the same season. Mating starts during the migration southward in late fall and continues through the winter calving or nursing areas. Calves are produced between late December & early March after a gestation of 11 - 13 months. For 7-8 months, mothers & calves are inseparably linked till the calf is weaning. The calf will drink up to 1800 liters of milk each day during this period. Gray whale milk is denser than any other recorded whale or dolphin species, with 53% fat and 6% protein. During the northward migration, mothers and calves stay near shore (typically within 200 meters of the shoreline), perhaps to prevent being attacked by killer whales. Mothers are very loyal to their calves and will fight to the death to defend them.

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