Gray Whale: where and when to see them

The gray whale is a baleen whale of the North Pacific, recognizable by mottled skin, barnacle patches and the absence of a true dorsal fin. The eastern population undertakes a long migration between northern feeding grounds and wintering waters off Mexico. Western North Pacific animals have a different and more precarious conservation history. These whales are entirely marine, although their coastal movements sometimes make distant observation possible from land.

Size

11-15 m long

Weight

20-40 tonnes

Lifespan

Not reliably established

Status

Least Concern

Gray whales commonly travel alone or in small, loose groups, surfacing in a sequence of breaths before a longer interval out of view. Many feed by rolling onto one side and disturbing bottom sediment, then straining small animals through baleen. Mothers accompany calves on the northward migration. Breaching and spyhopping occur, but most shore observations involve brief views of blows, a rounded back or tail flukes disappearing offshore. Gray whales are known for their curiosity towards boats in certain areas, particularly in Baja California lagoons where they sometimes approach vessels voluntarily. This 'friendly' behavior is a remarkable aspect of their interactions with humans. During migration, they generally travel close to shore, making them one of the most accessible large whales for land-based observation.

• Some individuals migrate more than 15,000 km in a round trip.
• Their feeding can leave elongated pits in soft seabed sediment.
• Barnacles and whale lice contribute to their patchwork appearance.
• The species once inhabited the North Atlantic but disappeared there centuries ago.

In Mexico, January through March broadly overlaps winter lagoon use and coastal migration. Alaska's south coast can offer spring passage, especially April and May, while some northern feeding areas are relevant in summer. Exact timing shifts annually and differs markedly between coastlines. The peak of the southbound migration past California, often visible from shore, is typically in December and January. Northbound migrants, including mothers with young calves, can be seen along the Pacific coast from February through May. Early spring offers the best chances to witness the northward journey of cow-calf pairs.

They use shallow continental-shelf seas, coastal migration corridors and sheltered winter lagoons. Alaska supports important feeding areas, while Baja California contains major wintering grounds. Some animals also feed farther south during summer, and migration routes vary with age, reproductive condition and food availability. They undertake one of the longest annual migrations of any mammal, traveling up to 10,000 to 12,000 miles round trip between their feeding and breeding grounds. The lagoons of Baja California, like San Ignacio and Ojo de Liebre, are crucial calving and nursing areas. While most migrate, a small resident population also exists in the Pacific Northwest.

Their diet includes amphipods and other small bottom-dwelling crustaceans, along with mysids and locally available schooling prey. Gray whales filter food through short baleen plates. Feeding strategies are flexible, and some groups exploit prey in the water column rather than sediment. Their unique feeding method, known as 'benthic suction feeding,' involves stirring up sediment with their snout and filtering out prey. They typically feed by diving to the seafloor, turning on their side, and creating a suction to draw in sediment and organisms. This specialized technique allows them to exploit abundant food sources found in soft bottom sediments.

Common name

Gray Whale

Scientific name

Eschrichtius robustus

Animal group

Marine life

Size

11-15 m long

Weight

20-40 tonnes

Lifespan

Not reliably established

Status

Least Concern

Identification

Unlike humpback whales, gray whales lack a dorsal fin and instead show a low hump followed by a series of knuckles along the rear back. Their mottled gray skin, covered in barnacles and whale lice, creates a unique, often patchy appearance. Many individuals bear scars and white patches from past encounters or infestations. These natural markings can sometimes be used for individual identification by researchers.