Eschrichtius robustus

Gray whale is also known as gray whale in English. Its body circumference is larger than that of baleen whales, but smaller than that of right whales.

On the North American side of the Pacific Ocean, gray whales pass through the Bering Strait and the northwest Bering Sea from late May to late October to feed in the Arctic Circle where the water temperature and light are more suitable, and then begin to move south, passing through the Aleutian Islands and heading south along the coast of the North American continent, traveling an average of about 185 kilometers a day. In February, they breed on the west side of the California Peninsula and the south side of the Gulf of California, where the water temperature is high and the sunlight is sufficient. After February, they start to move north again, but the route is different from the southward. The round-trip distance from the summer feeding grounds to the winter breeding grounds is about 18,000 kilometers. On the Asian side of the Pacific Ocean, gray whales enter the Sea of Japan from the Sea of Okhotsk through the Soya Strait, then pass along the east coast of North Korea to reach the South China Sea. Some of them pass through the Tsushima Strait and go north to enter the Yellow Sea of China. The migration distance can be as long as 10,000-22,000 kilometers.

Gray whales mainly feed on small planktonic crustaceans, herring eggs, and other schooling fish. They also eat sea urchins, starfish, conchs, hermit crabs, sea shrimps, sea cucumbers, and seaweed. But they do not eat when migrating southward, and their stomachs are empty. They often eat when migrating northward.

Gray whales also take a few breaths during shallow diving, and then go on a long deep dive. The diving depth is about 100 meters, and the underwater distance is about 1,000 meters. The duration is generally 17 to 18 minutes. During shallow diving, the tail fin does not appear above the water surface, and the back does not bend, but during deep diving, the tail fin is often raised above the water surface. Its swimming speed is very slow, generally 3-4 nautical miles per hour, and the fastest does not exceed 7 to 8 nautical miles.

Some gray whales particularly like to make a "humming" sound, no matter when and where, about 50 times per hour, each time lasting 2 seconds, with a frequency range of 20-200 Hz and an intensity of up to 160 decibels, which is very much like sighing or mumbling. People are still unclear about the reason why it makes this sound. Some people think it is a signal of echolocation or communication between group members, and some people think it is a response to natural phenomena such as storms and earthquakes. Recent discoveries show that most of the individuals who make this sound are those who have not found a mate, so it is speculated that this "humming" sound may be their sigh for "lost love" or a kind of resentment and venting.

The main natural enemy of gray whales in the ocean is killer whales. They are often attacked by killer whales. At this time, they can only float on the water with their belly facing up and try to avoid disaster by pretending to be dead.

Gray whales mate in January and February, and females reproduce about once every year. The gestation period is about 12 months, and one calf is born each time. They give birth in the shallow coast of the wintering area in January and February of the following year. They are the only baleen whales that reproduce and give birth in shallow waters. The calf is 4-5 meters long at birth, and can reach 9 meters after one year. Females refuse to contact males after giving birth, and males can only look for other females who have not given birth to mate. Males are very attached to females, and females are very attached to their calves, but females are not attached to males. Therefore, if a female or a calf is threatened, both males and females will rush to rescue them, but if a male is in danger, he will not be rescued.

Genetic studies and differential recovery patterns show that the Northwest Pacific subpopulation of gray whales is independent of the Eastern Pacific subpopulation, and the former is listed as a critically endangered species. Gray whales in both the Eastern and Western Pacifics have been recorded to have been hunted by megalodon sharks in prehistoric times. In the early 20th century, the number of indigenous whaling along the coast dropped to a low level, and the rise of commercial whaling caused the depletion of fish resources, which seriously weakened the traditional fishing and hunting economy. In the mid-19th century, commercial whaling activities in the lagoon breeding area led to a sharp decline in the number of Eastern Pacific gray whales. From 1855 to 1865, during the ten-year peak whaling period, the annual catch was about 480. Surveys from 1967 to 1996 showed that despite continued fishing, the number of gray whales in the eastern Pacific was recovering at an annual rate of 2.5%, reaching a peak of 24,000-36,000 in 1997-1998, and falling to 15,000-22,000 in 2001-2002. There are many explanations for the decline in the population, the most likely being related to food acquisition and environmental carrying capacity. The number of gray whales in the western Pacific has remained at the same level as in the past, at around 100-300.

Listed in the "National Key Protected Wildlife List": National Second Class Protected Animal.

Listed in Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).

Listed in the 2008 Red List of Endangered Species of the World Conservation Union (IUCN) ver 3.1, the Eastern Pacific subpopulation is listed as a species of least concern (LC), and the Western Pacific subpopulation is listed as a critically endangered species (CR).

In February 2021, it was listed in the first level of the "List of National Key Protected Wildlife in China".

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Gray whales are distributed in the North Pacific, North Atlantic, North American coastal areas, the Sea of ​​Okhotsk, the Bering Sea, the Sea of ​​Japan, and China's Yellow Sea, East China Sea, South China Sea and other temperate waters.
Main distribution countries and regions (seas): Canada, Mexico, Russia, the United States, China, Japan, North Korea, South Korea.
Natural habitat is on the east coast of the Pacific

Gray whales are gray, dark gray or blue-gray with white spots, hence the name. Some people also call it the "gray rocky shore swimmer". The color of the ventral surface is lighter. The skin on the back of the body is uneven, mainly due to scars left by scratches from rocks or sand and parasites such as barnacles. Its eyes are oval, located behind the corners of the mouth, higher than the eyes of other baleen whales, and the upper eyelids are slightly longer. The ear holes are large, and a pencil can be inserted. They are located between the eyes and the base of the flippers. The baleen is light yellow, about 140-180 on each side, and 40-50 cm long. The baleen plate is thick, the baleen hair is rough, and the entire baleen plate gives people a heavy feeling. It also has more hair on its head than other baleen whales, and the arrangement is irregular. The front ends of the upper and lower jaws are the most, and the base of the hair does not form a tumor-like bulge. The tongue i