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 Grays 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 CabrilloNational Monument, where you can witness the annual winter journey.

Quick Whale Facts

• Adult Pacific Gray Whales can be 45 feet long and weight up to 33 tons.
• Gray whales make the longest migration of any mammal on Earth - 10,000 miles round trip.
• 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 can live 40 to 60 years.
• 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.

When To See Whales

Mid-January is the peak of the migration, but the Grays are visible from mid- to late December through March.  The heights around the park's Whale 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 anytime 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.  A movie about the Pacific Gray Whale is shown several times a day during whale season.

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, the 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 the cool air at the ocean surface, it creates the 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 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 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.

How Come We Don't See as Many Whales as We Used To?

At the whale overlook, Park Rangers hear it all the time:  “How come we don't see as many whales as we used to?”  Many visitors remember seeing more gray whales from CabrilloNational Monument during the 1970s.  Are they seeing fewer whales?  The answer is yes, despite an overall increase in the gray whale population.  Do we know why?  No, but researchers are trying to find out.

Several years ago, biology students under the guidance of Dr. Jim Sumich, a whale biologist with Grossmont College in San Diego County, observed the annual winter gray whale migration from CabrilloNational Monument.  Each Monday, Wednesday, and Friday morning during the season (December through February), these diligent biologists could be seen at the whale overlook patiently recording the direction, numbers, and behavior of the passing whales.

So what did we learn?  Gray whale census counts by the National Marine Fisheries Service from CabrilloNational Monument in 1979 did report more whales - up to 40 whales in one hour during the mid-January migration peak. Today, only about eight whales are visible each hour.  Curiously, this drop in shore sightings coincides with a dramatic increase in the overall population of gray whales.  In 1979, 15,000 gray whales were estimated to exist.  Today that number is more than 25,000.  A large percentage of whales in recent years, about 65% in 1993-94, migrate too far off the Southern California coast for watchers to see from shore.  This does not seem to have occurred in the late 1970s.

Some San Diegans believe this is because the animals are being harassed by a growing number of boaters in the waters off San Diego, particularly whale-watching boats.  Dr. Sumich, however, believes many reasons could account for the whales' behavior, including water quality changes, military and commercial boat activity, natural shifts in migration routes, or all of the above. Nevertheless, he believes that at least part of the reason is whale-watching boats.  Of particular impact, he feels, is the increasing number of private vessels hoping to get a closer look.  Federal law does not allow boaters to move within one hundred yards of whales (unless the animal moves closer on its own), but the rule is ignored by some boat captains.  From the whale overlook it is not uncommon to see a whale being pursued by a dozen or more boats on a busy weekend, or to see whales take evasive action to avoid boats.

Are the boats responsible for us seeing fewer whales today than fifteen years ago?  Only the whales know for sure.  In the 1976 gray whale census report, referring to San Diego, Dale W. Rice wrote that “The marked decline in the Point Loma counts in the late 1960s was thought to be due to harassment of the whales by increasing boat traffic, causing them to migrate farther offshore.  Even considering the better weather [in 1976], the [higher than average] count at Point Loma this year is unexpected.”  This seems to indicate that the whales have migrated far off shore in the past, too.  If this is so, perhaps we will see 40 whales an hour again soon!

The National Park Service supports long-term research efforts like the gray whale census, because good data collected over a long period helps us better understand whale migration trends and avoid jumping to conclusions about gray whale behavior today, and tomorrow.

If you visit the park on a clear sunny morning, mid-December to mid February, you may see the passing gray whales for yourself - and develop your own theory for why the whales do what they do.