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Gray Whale Migration Facts – Everything You Need to Know

a person flying through the air over a body of water

Gray whales are magnificent creatures. They travel through the San Diego area from frigid to warm waters, with new babies born on each trek. Seeing them in San Diego Bay is a once-in-a-lifetime experience. Keep reading to learn more about gray whale migration, biology, conservation status, and other fascinating facts. 


Gray whale populations live in the Pacific Ocean. They prefer coastal areas around Japan, Alaska, western Canada, and the Western United States. Gray whales also live around the eastern coasts of Korea, China, and Russia. 

Gray whales migrate around 10,000 miles round trip, with some groups traveling up to 14,000 miles. Eastern North Pacific populations migrate from northern Alaska to Baja California, passing through the San Diego area during their journeys. Ocean science blog oceanbites includes a gray whale migration map from the National Oceanic and Atmospheric Administration. The map shows that their lengthy trip route remains within 2.5 miles of the nearest shoreline. 

Scientists still don’t completely understand why gray whales migrate for such long distances. Like humpbacks and other baleen whales, they travel from colder feeding grounds to warmer waters where they reproduce and nurse their young. The current working theory is that whales birth calves in warmer waters to help them thermoregulate. Since newborn whale calves don’t have enough fat to keep them warm, they may not thrive as well in frigid Arctic waters. 


Gray whales are part of the Baleen whale family. Their mouths are full of baleen: slender durable keratin structures that resemble the teeth on a comb. With their baleen, they strain and eat smaller life forms from the ocean. Gray whale diets consist of krill, small fish, and plankton, a class of ocean microorganisms that include algae, unicellular and multicellular animals, fungi, and bacteria. 

Gray whales have unique physical structures. They don’t have dorsal fins: Their bodies have a single hump followed by a row of sharp bumps on their backs. Their pectoral fins work like flippers, which they use to balance and steer their bodies. NOAA states that adult gray whales can grow up to 50 feet long and weigh around 90,000 pounds.

a whale jumping out of the water

Why Are They Special and Important?

Gray whales enjoy protection under the Marine Mammal Protection Act of 1972. Before the 20th century, this species had large populations throughout the world. However, they almost became extinct after extensive hunting. The International Whaling Commission gave gray whales complete protection in 1947, which helped save them from total extinction.

While eastern gray whales have recovered from their critically low numbers, western groups remain endangered. North Atlantic gray whales have been extinct since the 1600s. The Alaska Department of Fish and Game estimates the current Eastern North Atlantic population at 26,000. These beautiful and intelligent animals are the same ones who pass through San Diego Bay every winter and spring. 

Gray whales have made a significant comeback, but they still face several threats in the wild. Besides natural enemies like orcas, they face other challenges: net fishing entanglement, plastic waste in the ocean, and climate change. Global temperature increases and Arctic ice melting may jeopardize their Arctic feeding grounds. 

Best Season to See Them in San Diego

Gray whale migration in California occurs from December until March, when the Eastern North Pacific population travels to warmer Mexican waters. Gray whale calves are born during this time. They nurse for seven to eight months, developing critical fat stores before returning to the Arctic with their mothers. 

When whale-watching in the San Diego area, you may see mother-calf pairings. Gray whales are naturally curious and friendly creatures, but mothers are known to approach vessels with their calves. Schedule a whale-watching voyage with Next Level Sailing to see these fascinating animals in their natural settings.