Gray whales: what you need to know about our West Coast Leviathans and their uncertain future
When Californians think of whales, they usually think of the species most seen off our coasts: gray whales.
Swimming north and south, springing up, sticking their heads out of the sea, and endlessly curious about the humans they meet, gray whales are awe-inspiring creatures. They too are in trouble. More than 480 have been mysteriously found dead in the Eastern Pacific since 2019.
Basic facts about gray whales
- Length: Up to 49 feet
- Weight: 90,000 pounds, more than a fully loaded semi-trailer
- Color: The gray whale was named for the gray spots and white mottling on its dark skin.
- Lifetime: Unknown, but estimated to be 40 to 80 years old.
- Speed: Usually 3-5 mph, but can swim twice that speed when in danger.
- Population: Approximately 19,000 (eastern Pacific gray whales)
- Scientific name: Eschrichtius robustus
Gray whales spend the winter in the shallow lagoons of Baja California, Mexico, where females nurse their young and others frolic and mate. They then move north to the Pacific coast to the waters off Alaska, their historic summer feeding grounds. Then, as winter approaches, they head south to Baja.
- Coupling: Gray whales reach sexual maturity between 5 and 11 years old.
- Birth : Mother gray whales nurse one calf at a time.
- Pregnancy: The gestation period is 12 to 13 months.
- Baby food: Whales are mammals, so newborn calves suckle their mother’s milk.
- Complaining: Fat is needed for energy and also for insulation when whales reach the cold Arctic waters. Mothers and calves spend about two to three months in Baja before traveling north so the baby whales can accumulate fat.
The lingo of whales and dolphins
Test your knowledge of whale watching terms:
- Killer whales : Also known as killer whales, orcas are often described as “the gray whale’s # 1 enemy”. There are two main types of killer whales: “resident” killer whales, which feed primarily on fish, and “transient” killer whales, which travel in packs and feed on marine mammals. Gray calves are particularly vulnerable.
- Collisions with ships: Scientists estimate that ships strike and kill dozens of whales off the west coast of North America each year. Over the past 15 years, global maritime traffic has tripled. Some projections predict that it could grow 1,200% more by 2050.
- Food supply: In the Arctic, gray whales have historically fed on a species of amphipod – a type of crustacean – which has largely disappeared. As a result, the gray whales have been forced to consume another species, and it is not known whether this new food source is as nutritious as the previous one.
- Noise: Unnatural underwater sounds from boats, seismic air cannons, and other sources can disrupt communication between whales and, in extreme cases, can lead to hearing loss and a depressed immune system.
- Fishing equipment: Thrown nets and traps can entangle and injure whales and make them more vulnerable to predators.
- Other pollution: Whales that migrate near the west coast are exposed to toxic runoff waves from stormwater, sewage plant failures and industrial discharges. While feeding, they also encounter garbage thrown by boats and left on beaches.
Some other whales from the eastern Pacific
Blue whale: Growing up to 98 feet in length, blue whales are the largest of all whales and the largest of all living creatures. Like other large whales, they were almost hunted to extinction.
Fin whales: Slightly smaller than blue whales, fin whales are the second largest leviathan.
Humpback whales: Named for their unusual body shape, humpback whales have long pectoral fins and buttons on their heads. Males produce a complex song that can last up to 20 minutes.
Sperm whales: Unlike gray, blue, humpback, and fin whales, sperm whales have teeth and are known as the world’s largest toothed predator.
Sources: National Oceanic and Atmospheric Administration (NOAA); International Whaling Commission; Alaska Department of Fish and Game; Travel to the North.
This story originally appeared in the Los Angeles Times.