Gray Whales: Mud, Mating and Migrating

A gray whale. Photo courtesy of NOS/NOAA/MBNMS.

Two gray whales. Photo courtesy of NOS/NOAA/MBNMS.

Have you seen any heart-shaped puffs of mist from the ocean offshore California lately? If so you were likely close to a gray whale. Gray whales arguably hold the record of having the longest mammal migration on earth and they are passing by Central Coast waters now. Starting in winter, gray whales (Eschrichtius robustus), are off on their 11,000-mile trip south and then head back north to the Arctic by summer.

The Great Migration: When to See it

Grays begin their migration in November heading south to the bays and lagoons of Baja California. Most of the whales passing the Central Coast during November and December are pregnant females racing to warmer waters to give birth. In mid-January, the rest of the gray whale population passes by.

They return north from mid-February to early summer; this is peak migration time and the Monterey Bay is a great food source. Northwest winds push the surface water offshore, replacing it with nutrient rich cold water from greater depths. This “upwelling” fuels the growth of plankton which are the basis for the Monterey Bay National Marine Sanctuary’s rich marine food chain. The richest waters are centered along the submarine canyons that come close to shore. Look for them just beyond the kelp forests. The gray whales come close enough that you can see the growth of whitish barnacles and pink “whale lice” on their skin – even without binoculars.

The gray whale migration route. Photo courtesy of NOS/NOAA Fisheries.

The gray whale migration route. Photo courtesy of NOS/NOAA Fisheries.

Mud Munching

Grays feed in a very unusual way. They dive to the bottom, lay on their sides and scoop up great gobs of mud which they filter through their baleen. The bristles of the baleen trap inch-long, fat-rich amphipods that get whisked down their throats using their huge tongue. Grays spend the summer in the Bering Sea or the Chukchi Sea, between Russia and Alaska feeding on the food rich muds.

Read the whole story here at to find out just how big these giant beauties are and why gray whales have been taken off the endangered species list.

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Julia Gaudinski

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