Gray whales are named for the distinctive gray and white patterning, which is unique to each individual. Their white patches are mostly made up of barnacles and lice that have attached themselves to the whale’s body. In fact, gray whales can carry over 400 pounds of barnacles and whale lice.
Female gray whales are usually larger than males, reaching up to 49 feet in length and 80,000 pounds.
With no dorsal fin, gray whales instead have a low hump and a series of six to 12 knuckles or bumps. They also have sparse hairs around their snout, especially young whales. Their spouts are usually low and puffy or heart-shaped.
Gray whales are baleen whales, with approximately 300 plates of cream-colored baleen hanging from their upper jaws. Two to five throat creases allow their throats to expand during feeding.
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Habitat & Population Status
There are two stocks of gray whales—the Eastern population, which is found along the coasts of the United States and Canada, and the Western population, which is found along the coasts of Russia and Japan.
The Eastern stock of gray whales spends their summers north of Alaska in the Bering and Chukchi Seas and migrates south to the waters of Baja California, Mexico, for the winter. As a species that generally stays around the continental shelf, gray whales are a truly coastal species.
In the late 1800s, humans discovered gray whale breeding grounds, killing a large percentage of the population. This massive drop in numbers made it no longer profitable to hunt gray whales, and their population slowly recovered.
However, the early 1900s brought the invention of factory ships, which processed whales aboard the vessels. This new technology allowed intensive hunting on gray whales once again. Their population decreased dramatically to approximately fewer than 2,000 individuals.
Protection finally came in 1946 through an international agreement to stop hunting gray whales. Since then, the population has grown to 26,000, similar to what it was before modern-day whaling, which resulted in gray whales becoming one of only two species to ever be removed from the Endangered Species List.
Unfortunately, the Western stock is on the brink of extinction with only 100 to 150 individuals left today. Another group of gray whales once lived in the North Atlantic Ocean but became extinct in the 17th century due to hunting.
In 2019, gray whales began washing up along the west coast of North America in high numbers, leading the National Oceanic and Atmospheric Administration (NOAA) to declare an Unusual Mortality Event for this group. Scientists at the Center investigated several of these strandings and linked almost all of the deaths to malnutrition and ship strike. NOAA Fisheries estimates gray whales have lost nearly a quarter of their overall population during the latest mortality event.
Gray whales have one of the longest annual migrations of any mammal. During summer they live in Arctic regions that are rich in their food. As baleen whales, gray whales eat through filter-feeding by opening their mouth to take in water then pushing the water back out through their baleen while their food remains in their mouth.
Muddy patches of water are often seen in places where gray whales are feeding. Although they feed primarily in the Arctic, some have been observed feeding during their migration as well.
As fall approaches, there is less sunlight and less food, and the water turns cold in the Arctic. This is when the whales travel to Baja California, Mexico, where they enter warm lagoons to mate and give birth.
Female gray whales sexually mature at around 8 years old, and usually give birth every two to three years, with their pregnancies lasting about one year. Newborn calves are typically born in January and February, averaging about 14 to 16 feet in length and weighing about 2,000 pounds. Calves stay with their mothers for about eight months and even migrate with their mothers back to the Arctic feeding grounds.
Gray whales can be seen passing by California in December and January during their southern migration, and again between March and May on their journey north.
Since gray whales migrate relatively close to shore, whale watching is very popular. People have many opportunities to see gray whales from coastal cliffs and headlands or from whale-watching boats.
Learn more about how to see the gray whale migration along the California coast, including tips for sighting gray whales and where to see whales from shore.