Gray Whale Migration – Witness the Annual Winter Journey
Each winter, the Pacific gray whales pass by the western overlooks of Cabrillo National Monument. After spending the summer feeding in the food-rich waters of the Arctic, the whales swim south along the coast to the bays of Baja California, where they mate and nurse their young. Along the way, they pass Point Loma and Cabrillo National Monument, where you can witness their annual winter journey.
Interesting Whale Facts
Adult Pacific gray whales are 30 to 50 feet long and weigh from 20 to 40 tons.
Baby gray whales average 15 feet in length and weigh about a ton.
A mother gray whale’s milk is more than 50% fat.
Gray whales live 20 to 40 years on average, and some live 60 years. They reach sexual maturity at eight years.
Gray whales make a series of grunts, clicks and low rumbles to navigate and communicate among themselves. They don’t ‘sing’ elaborate songs like humpback whales.
Instead of teeth, gray whales have long sheets of baleen (made of the same material as your fingernails) hanging from the roofs of their mouths. They use these comb-like sheets to filter food from the water.
Gray whales eat tiny animals called amphipods. Millions of amphipods live in the muddy Arctic seafloor. Lying on its side, a gray whale slurps up mouthfuls of mud and water, then filters out the amphipods through its baleen.
A gray whale’s skin is dark gray. But it is mottled with scars and patches of light-colored barnacles growing on its back. Each whale has its own distinctive pattern of barnacles and scars, and scientists use these patterns to identify individual whales.
Gray whales have six to 12 knobs, or bumps, along the tops of their tail ridges instead of a fin like some other whales.
Killer whales, large sharks and people are the gray whales only known predators.
Gray whales were nearly hunted to extinction in the 19th century.
Gray whales have been protected from exploitation by the International Whaling Commission since 1946. As a result, current populations are considered close to their pre-exploitation numbers.
A Gray Whale’s Year
When gray whales appear off our coast in December, they are nearing the end of a long journey from Arctic waters to the lagoons of Baja California. It’s one leg of a round-trip migration of nearly 12, 000 miles—the longest of any mammal:
Summer: Gray whales summer in the waters off Alaska and Siberia. The Arctic seas produce tons of amphipods that are the staple of a gray whale’s diet. Feasting on this bounty, the whales build up a layer of blubber that serves as insulation and as a food reserve. In late September, grays begin the southern migration. Except for an occasional meal along the way, they won’t eat again until they return the following summer.
Fall: Migrating whales arrive along the Oregon and northern California coasts in late November and early December. Most pass San Diego in late December, January and February.
Winter: Grays mate and give birth in the warm, shallow lagoons of Baja California from January through March. A cow mates one year, then returns to give birth the next.
Spring: In late February, some grays begin swimming north. Cows with calves are the last to leave the lagoons, remaining until March or April.
When To See Whales
Mid-January is the peak time for migration, but whales are visible from mid- to late December through March. The heights around the park’s Kelp Forest Overlook and Old Point Loma Lighthouse offer the best viewing. Bring binoculars if you have them: binoculars make viewing much easier and more enjoyable. A limited number of binoculars are available with a picture ID at the Visitor Center during whale season; ask for them at the information desk.
As the whales swim 24 hours a day, it’s possible to see them at any time during daylight hours. Park staff will gladly help you spot a whale. Check at the Visitor Center for information about ranger talks and whale watching.
Where to Look
Look west from the park overlooks, toward the ocean. The whales are migrating from the Arctic to the warm bays of Baja California and mainland Mexico, so they will be moving from the north (right), to the south (left) as you look from the park. Expect them to be moving at a steady speed of four or five knots, or about five miles per hour. Although some swim close to shore, most whales swim in an area that extends from the kelp beds (about three quarters of a mile out) to the horizon. Later, in the spring, gray whales will migrate north again, but they are generally too far out in the ocean to see from the park, even with binoculars.
What to Look For
The Blow or Spout
When warm, moist air exhaled from the whales’ lungs meets cool air at the ocean surface, it creates a bushy column we call a blow, or spout. A gray whale’s blow is up to 15 feet high, and each blow is visible for about five seconds. Anticipate that the whale will dive for three to six minutes, then surface for three to five blows in a row, 30 to 50 seconds apart, before diving deep for three to six minutes again.
The Flukes (Tail)
Before making a long, deep dive, a gray whale often displays its 12-foot wide fan-shaped flukes, or tail. The weight of the tail above the whale’s body helps the whale to dive deep. The flukes have no bones and connect to the body and tail muscles by banks of tendons. The gray whale normally swims about five miles per hour, about the speed of a child on a bicycle.
The Knuckled Back and Footprint
If the lighting is right, and if the whale is close enough, it is possible to see the back of a gray whale during and after the blow. It is shiny and black or gray, with a knuckled ridge along the spine. After the whale submerges you may note an elongated, smooth oval of calm water, known as a footprint, where the whale has been.
Breach and Splash
Gray whales occasionally hurl themselves out of the water and plunge back in with a tremendous splash. This is called breaching. Scientists do not know why gray whales do this, but it is a very exciting sight to see. Sometimes other whales in the area will copy this behavior, so keep your eyes open.
Once You Have Spotted a Whale…
Remember that they are migrating south, which is to your left as you look west out over the ocean from Cabrillo National Monument. Once you have spotted a whale, you can expect that it will surface again to the south. After watching an individual gray whale for a while, you will be able to anticipate its unique rhythm of breaths and dives, and where it will surface next.
CNM hosts a Whale Watch Weekend and Intertidal Festival every year during late January or early February. The festival includes lectures, exhibits, presentations, demonstrations, kids’ activities, films and more. Rangers and VIPs are on hand to assist visitors in spotting whales (and giving out stickers), and doing walks and talks in the tidepools. Check the event calendar for dates and times, and sign up to volunteer!
Last revised 06-Aug-14