It’s a whale of a time to watch people on boats.

Now is the time to see whales.

Or, from the whale’s point of view, now is the time to see humans.

By the hundreds, the latter abandon their usual land habitat to get on boats and chug over to the whales’ freeway off the South Bay coast.

Many obligingly lean over railings and point. Others aim strange, clicking contraptions with lenses. Some come in pairs. Many bring their young.

Scientific-minded whales, if there are any, must speculate about the humans’ strange seasonal behavior: Is it somehow related to mating instincts or child-rearing habits?

Whatever the point of view, the largest mammals will meet the brainiest between now and April as thousands of gray whales pass by the South Bay coastline on their 12,000-mile round-trip migration from the Bering Sea off Alaska to the lagoons of Baja California. That’s where they mate and bear their young.

The giant swimmers--which can reach 50 feet in length and weigh 50 tons--spout, lunge out of the water and flash their tail flukes as they plunge back into the sea.

The humans come out of San Pedro, Redondo Beach and Long Beach on two- to three-hour whale-watching boat trips. Besides whales, they are likely to encounter schools of dolphins, various sea birds and even sea lions.

The other afternoon at San Pedro, a boatload of whale-watchers saw as many as 10 whales, including one that swam within 15 feet of the boat, according to Merja Heikkila of Finland, who was with her husband, Timo--a business student at USC--and their 10-month-old daughter, Krista.

“It was amazing,” she said. “It was the first time for us. We’d never seen whales. What a thrill.”

Another USC student, Art Jaklitsch of Columbus, Ohio, also saw whales for the first time. “It was fantastic,” he said. “We have Lake Erie, but we don’t have whales.”

Jim Peterson, who runs the Sport King out of San Pedro, said whale watching has been pretty steady for the last two weeks. “The migration is in full swing,” he said.

Peterson said the most common thrill occurs when whales take a deep breath, arch their backs and “sound”--dive for as long as 40 minutes, although 10 to 15 minutes is normal.

“People really get excited when they lift their tails out of the water,” he said.

Rarer sights include a mother and calf, the mighty sperm whale and breaching whales.

When a whale breaches, it breaks the surface in a spectacular leap and crashes down with an enormous splash.

“We have had two breach right in front of the boat,” Peterson said.

Why do they do it?

“Some people say they are looking around for land bearings,” Peterson said. “Some people say they are trying to knock some barnacles off their bodies. Some say they are showing off for their mates. Sometimes they will do it one time. One time we counted as high as 25 times. Generally, they do it three to four times.”

Peterson also spotted a mother and calf this year. “Everybody says, ‘How cute!’ We generally don’t stay with the mothers with calves very long,” he said. “They are very nervous.”

And earlier this year, he saw three sperm whales.

“They were lying on the surface for 15 to 20 minutes,” he said. “When they did sound, we never did find them again. They can stay down a lot longer than the gray whales.” Sperm whales have been known to go as far as a half-mile down and stay underwater for up to 75 minutes.

If you want to go whale-watching, you can go to San Pedro, Redondo Beach or Long Beach.

Ports O’Call Village, along the main channel of Los Angeles Harbor near Harbor Boulevard and 6th Street in San Pedro, has several boat operators:

Los Angeles Harbor Sports Fishing, Berth 79. Monday-Friday, 10 a.m. and 1 p.m.; Saturday-Sunday, 11:30 a.m. and 2 p.m.; $10 adults, $7 children 12 and under; weekend early-bird special, 9 a.m., $5. Reservations, 547-9916.

Spirit Adventures, Berth 75. Daily Monday-Friday, twice-daily Saturday-Sunday. Call 831-1073 for times; $12.50, $10 weekdays with advance reservations.

Los Angeles Harbor Cruises, Village Boat House, Berth 77. Saturday-Sunday, 11:30 a.m. and 2 p.m.; $12 adults, $5 children 2 through 12, under 2 free; information, 831-0996.

Buccaneer-Mardi Gras Cruises, Berth 76. Saturday-Sunday 12:30 p.m. champagne brunch on Buccaneer Queen, replica of 18th-Century pirate ship; $24, including meal and cruise. Reservations, 548-1085.

Pilgrim, replica of American Revolutionary War ship, Berth 76. Saturday-Sunday, 11 a.m. and 2 p.m.; $12 adults, $6 children 12 and under; reservations, 547-0941.

Also in San Pedro is Skipper’s 22nd Street Landing, 141 W. 22nd St., San Pedro. Monday-Friday, 10 a.m. and 1 p.m.; Saturday-Sunday, 9 a.m., 11:30 a.m. and 2 p.m.; weekdays, $10 adults; $7 children 12 and under and seniors 62 and over; weekends, $11 adults, $8 children and seniors; reservations, 832-8304.

In Redondo Beach, there is Redondo Sportsfishing, King Harbor, 233 N. Harbor Drive; Monday-Friday, 10 a.m. and 1:30 p.m.; Saturday-Sunday, 9:30 a.m. and 1:30 p.m.; weekdays, $6.50; weekends, $9 adults, $6.50 children 11 and under. Reservations, 372-2111.

In Long Beach, there are three operators:

Catalina Cruises, Catalina Landing, 312 Golden Shore Drive, Long Beach Harbor. Saturday-Sunday, 10 a.m. and 1:30 p.m.; occasional 11 a.m. weekday cruises; $11 adults, $10 seniors 55 and over, $9 children 5 through 11, $2 children under 5. Reservations, 514-3838, 775-6111.

Belmont Pier Sport Fishing, Ocean Boulevard and 39th Place; Saturday-Sunday, 9 a.m. and 1 p.m.; Monday-Friday, 10 a.m., if sufficient reservations are made; call 434-6781; weekends, $9, adults, $7, children 12 and under; weekdays, $7, adults, $5, children.

Long Beach Sportsfishing, Queen’s Wharf Landing, 555 Pico Ave., Berth 55, Long Beach Harbor; Monday-Friday, 10 a.m.; Saturday-Sunday, 10 a.m. and 1 p.m.; $9 adults, $6.50 juniors 15 and under and seniors 55 and over; reservations, 432-8993.

All whale-watch cruises are narrated, and boats serve refreshments. Most offer reduced group rates. Trained volunteer whale-watch guides from the Cabrillo Marine Museum in San Pedro lead most trips leaving from 22nd Street Landing, Redondo Sportsfishing, Catalina Cruises and Belmont Pier Sport Fishing.

Migrating whales also may be viewed from shore at the Point Vicente Interpretive Center, 31501 Palos Verdes Drive West, Rancho Palos Verdes. The center is open daily from 10 a.m. to 5 p.m.

The fifth annual Whale of a Day at the center will be on Saturday from 11 a.m. to 4 p.m., with crafts, whale talks, food and fun. Outdoor activities are free; entry to the museum is $1 for adults and 50 cents for seniors and children over the age of 3. Information: 377-5370.