Gray Whale (Eschrichtius robustus): Migration and Facts

What does a gray whale look like?

A gray whale is dark slate gray, heavily mottled with pale gray and white patches. Many of those patches are whale barnacles, clusters of orange-white whale lice and the round white scars left where barnacles have dropped off, especially on the head and back. Calves are born dark gray to almost black and grow paler and more patchy with age. Why so many hitchhikers live on gray whales is explained in Why do gray whales have barnacles?

The body is long and fairly slim, with a narrow, gently arched head and small eyes just above the corners of the mouth. Gray whales have no dorsal fin. Instead, there is a low hump about two-thirds of the way along the back, followed by a row of 6–12 small bumps called knuckles that run toward the tail. The broad tail flukes are nearly 3 m (10 ft) across, with a deep notch in the middle.

Under the chin are only two to five short throat grooves, far fewer than the many pleats of rorquals such as the blue whale. Gray whales have two blowholes, and in calm air their bushy blow can look heart-shaped from behind. The baleen is short, thick and creamy white or yellowish.

How big is a gray whale?

Gray whales are smaller than blue, fin or humpback whales but still huge. Females are slightly larger than males.

Weight changes a lot through the year. Gray whales put on a thick layer of blubber during the Arctic summer and then live largely on those reserves through the migration and winter, so they are much thinner by spring.

Where do gray whales live?

Gray whales live only in the North Pacific today. The large eastern North Pacific population spends summer feeding in the shallow Bering, Chukchi and Beaufort seas off Alaska and Russia, then migrates south along the coast of North America to spend winter in lagoons and bays of Baja California, Mexico. About 200 whales, known as the Pacific Coast Feeding Group, skip the Arctic and spend summer feeding along the coast between northern California and British Columbia.

A much smaller western North Pacific population feeds in summer off Sakhalin Island and Kamchatka in the Russian Far East. NOAA estimates it at fewer than 300 whales. Satellite tags and photo-identification have shown that some of these whales cross the Pacific to winter off Mexico, while others may still use routes along the coasts of Asia.

Gray whales stay closer to shore than most large whales, usually over the continental shelf, which makes them easy to watch from headlands. They once lived in the North Atlantic too, but that population died out centuries ago; see Are there gray whales in the Atlantic?

How do gray whales feed?

Gray whales are the only baleen whales that feed mainly on the seafloor. A whale dives to the bottom in shallow water over the continental shelf, rolls onto its side and sucks in sediment along with small animals living in it. It then pushes the mud and water out through its baleen with its tongue, keeping the food inside. Most gray whales seem to favor rolling onto their right side.

Their main summer food in the Arctic is small bottom-living crustaceans called amphipods, which form dense beds in the seafloor. Gray whales also eat ghost shrimp, mysid shrimp, marine worms, crab larvae, herring eggs and small fish, and they can switch to skimming swarms of prey near the surface or in kelp beds. Feeding leaves long trails of mud and shallow pits in the seabed. To compare their method with that of other filter-feeding whales, read What are baleen whales?

Migration

Every year, most eastern gray whales swim from the Arctic to Mexico and back, a round trip of about 16,000–22,000 km (10,000–13,700 mi). The southward journey starts in October and November, and the whales pass California mostly in December and January, traveling day and night at an average of about 8 km/h (5 mph). Pregnant females lead the way, and calves are born from early January to mid-February.

From mid-February to May the whales head north again. Males and females without calves leave first, and mothers with young calves follow later, often hugging the shore to avoid orcas. In 2011, a female from the western population tagged off Sakhalin, Russia, swam to Mexico and back, about 22,500 km (14,000 mi) in 172 days, one of the longest migrations ever recorded for a mammal. Find out more in How far do gray whales migrate?

Behavior

Gray whales usually travel alone or in small, loosely connected groups, although hundreds gather in the feeding areas and lagoons. Like other baleen whales, they rarely seem to form long-term bonds, except between a mother and her calf.

They are known for spyhopping, rising vertically to lift the head out of the water, and for breaching, especially in the lagoons and during migration. Gray whales also make low knocks, grunts, moans and pulses, but they are much quieter than humpbacks.

Whalers once called them devilfish because mothers fought fiercely when their calves were harpooned. Today the same species is known for the opposite behavior: since the 1970s, some gray whales in San Ignacio Lagoon and other Baja lagoons have approached small boats of their own accord, often with their calves.

Reproduction and calves

Gray whales reach sexual maturity at about 6–12 years, on average around 8–9. Mating takes place mostly in late November and early December, during the southward migration, and often involves three or more whales. Pregnancy lasts about 12–13 months, and most females give birth every two years.

The calf is born tail first, often in or near the shallow lagoons of Baja California, whose shallow, calm water may help protect it from orcas and sharks. It drinks rich milk for about seven months, building blubber before and during the long trip north to the Arctic.

How long do gray whales live?

No one knows exactly how long gray whales can live. NOAA notes that one female was estimated at 75–80 years old after her death, and photo-identification records in Mexico include females first seen in the 1970s that are still being photographed decades later. Most gray whales probably live for several decades if they survive calfhood.

Predators and threats

Orcas are the only natural predators of gray whales, and they target calves in particular. Groups of orcas wait along the migration route, for example in Monterey Bay in California and off Unimak Island in Alaska, to attack mothers and calves heading north. Mothers defend their young, and humpback whales have been seen interfering with such attacks.

Human threats include collisions with ships along one of the world’s busiest coastlines, entanglement in fishing gear, underwater noise, disturbance in the lagoons, and oil and gas development near Sakhalin. Climate change is a major concern. As Arctic sea ice shrinks, the amphipod beds the whales depend on are changing, and some whales are struggling to find enough food.

From 2019 to 2023, NOAA investigated an unusual mortality event in which nearly 700 dead gray whales stranded along the coasts of Mexico, the United States and Canada, many of them thin. Calf numbers have also fallen. According to NOAA’s shore counts, the eastern population fell from about 27,000 in 2016 to roughly 13,000 by 2025.

Conservation status

The IUCN Red List lists the gray whale as Least Concern as a species, while the western North Pacific population is listed as Endangered. Gray whales were hunted close to extinction twice: first in the 1850s and 1860s, when whalers found the Mexican breeding lagoons, and again in the early 20th century. International protection from commercial whaling began in the 1930s and 1940s.

The eastern population recovered so well that it was removed from the US endangered species list in 1994, a rare success. Small numbers are still taken by Indigenous communities in Chukotka, Russia, under an aboriginal subsistence quota set by the International Whaling Commission. Today the recent decline in the east and the tiny western population are the main worries. Gray whale migrations are also featured among the longest animal migrations on Earth.

Where to watch gray whales

The classic gray whale experience is a small-boat trip in the Baja California lagoons, such as Laguna Ojo de Liebre, San Ignacio Lagoon and Magdalena Bay, from about January to April, when mothers and calves are present. Mexico limits the number of boats and where they may go in these protected areas.

In the United States and Canada, gray whales can often be seen from land during the migration. Good spots include Cabrillo National Monument in San Diego, Point Reyes and Monterey Bay in California, Depoe Bay and other headlands in Oregon, and Tofino on Vancouver Island. Watch for the low, bushy blow, then the knuckled back and raised flukes as the whale dives. NOAA advises boats to stay at least 100 yards (91 m) from large whales.