January 21, 2020 • Ocean Facts, Resources, Travel Ideas
The annual gray whale migration is one of Earth’s greatest wildlife spectacles, and the California coast is an outstanding place to see migrating gray whales. Thanks to a moratorium on whaling and other multinational protections, the eastern Pacific population of gray whales is thriving with around 26,000 individuals, and a Red List status of Least Concern.
Gray whales are charismatic marine mammals that can reach 40-50 feet in length and weigh more than 36 tons (72,000 pounds) when fully grown. Gray whales are true to their name, and are dark gray in color with blotchy white patches. The white patches are variations in pigmentation, scars and even barnacles and whale lice. The latter two can contribute up to 400 pounds to the whale’s weight!
A gray whale breaches near Half Moon Bay, CA. © Rhys Watkin
Every year, gray whales undertake one of the longest migrations of any mammal, traveling 12,000 miles round-trip from their feeding grounds in the Arctic to calve and breed in the Baja lagoons, and then back again. That is about the same as traveling across the United States from San Francisco, California to Washington D.C., three times!
Gray whales spend their summers feeding in the nutrient rich waters of the Arctic, though some whales are seen further south during this time, even in California. Gray whales feed on small animals (usually amphipods) that live in the seafloor sediment. Like people, gray whales show left and right side preference! While eating, gray whales move along the seafloor on their side, using their baleen to sift their food from the sediment. Side preference can be determined by looking at the whale’s head—the side with fewer barnacles and some evidence of scraping on the skin is their preferred side.
Gray whales begin to leave their Arctic feeding grounds in September, migrating south along the coastline to breed and calve in Baja California, Mexico. Gray whales travel at approximately 5 miles per hour and average about 75 miles a day.
Adult females and males begin to arrive in the lagoons of Baja California. There are four lagoons in Baja that the whales inhabit. Pregnant females (carrying calves conceived a year earlier) are coming here to give birth in the sheltered, warm waters where they can nurse their calves and help them develop strength for the journey back north. Adult male and non-pregnant female whales also make the journey to Baja’s lagoons in order to mate.
January through March is an ideal time to see migrating gray whales along the California coast, with whales traveling both northward and southward. This is also the time during which gray whales arrive in Baja. Most whales arrive to Baja’s lagoons during January and February, and by mid-March the majority of the population has reached the lagoons where they will mate and calve.
Gray whale calves are born between the end of December and start of February. Newborn gray whale calves are about 15 feet long and weigh 1,500 lbs. During this time, the mother and calf pairs are known for their curious and “friendly” behavior, whereby they actively seek out interaction with whale watchers (e.g. “petting”).
Baja’s gray whale tourism started in the 1970s after it was discovered that the gray whales would not only approach boats, but also interact with those on board. The whales appear to seek out contact; approaching and rubbing against boats and loitering at or just below the surface while accepting rubs and pats from obliging travelers. © Slater Moore
Gray whales leave Baja’s lagoons to migrate back north starting at the beginning of February and continuing through April. This is an excellent time to see migrating gray whales along the California coast, with large numbers of whales traveling northward. Female whales with newborn calves are the last to depart to the lagoons in order to give the calves as much time as possible to grow. These mother-calf pairs tend to stay close to the coast throughout their migration, and will be looking to avoid predators, especially killer whales and great white sharks. Gray whale calves will nurse for approximately seven months and will stay by their mom’s side for up to nine months.
A breaching gray whale off the California coast during its annual migration. © Rhys Watkin
Led by Oceanic Society’s local wildlife experts, our whale watching trips provide opportunities to see blue, humpback, and gray whales, dolphins and porpoises, seals and sea lions, rare seabirds, and other marine life up close.
Gray whale flukes are more rounded than those of humpback whales, another common visitor to California. © Rhys Watkin
Beyond their coloration, there are a few distinguishing characteristics that can help you identify gray whales along the California coast.
Blow or spout: Like other baleen whales, gray whales have two blowholes. When they breathe out, the spray (also called the ‘blow’) sometimes takes the shape of a heart. Keep an eye out for these distinct puffs on the horizon!
Flukes: Gray whale flukes are rounder than the well-known humpback flukes, with a distinct heart-shape.
Distinctive Dorsum (Back): Gray whales do not have a dorsal fin. Instead they have a low hump and have a knobby/bumpy appearance.
Breaching Behavior: Though not quite as acrobatic as the humpback whale, gray whales will emerge from the water and land in a giant splash, a behavior known as breaching.
Naturalist Susan Sherman briefs Oceanic Society guests before departing on a whale watching trip. © Rhys Watkin
In addition to gray whales, there is some other wildlife you may spot on our whale watching trips.
Year-round: Harbor seals, California sea lions, and pelicans hang out year-round and, very rarely, sea otters make an appearance. You may also spot Risso’s dolphins, common dolphins, or Pacific white-sided dolphins.
January: Open ocean birds like murres and auklets seek a reprieve in calmer waters along the coast and elephant seal breeding season has begun at Año Nuevo State Park.
March – early April: Humpback whales can be spotted along the California coast. Humpbacks are almost black in color, with white markings along their underside, fins, and flukes (tail). Their flukes are wide with an uneven end, and their pectoral fins are long – almost one-third of their body length.
Harbor seals lounging on rocks. © Rhys Watkin
Oceanic Society is a 501(c)(3) non-profit organization dedicated to ocean conservation. Your participation in our whale watching trips helps fund our global ocean conservation programs and local programs including the Critter Scholars Program, which delivers life-changing ocean experiences free of charge to underserved student groups & communities around the San Francisco Bay Area. Also, we use our whale watching cruises as an opportunity to collect photographic identification data on marine mammals, which we share with a network of researchers throughout the eastern Pacific. You can see our recently photographed whales on Happywhale. For more information, see our Whale Watching page.