PESCADERO, Calif. – Each winter, Año Nuevo State Park in California becomes a bustling hub as around 10,000 elephant seals arrive to engage in their seasonal rituals of battling, mating, and birthing. This remarkable natural event, spanning from mid-December to March, attracts scores of wildlife enthusiasts eager to witness the grandeur of the world’s largest seals.

During what park docent Laura Stern refers to as the “pupping season,” massive bull seals—some stretching up to 16 feet (nearly 5 meters) in length and weighing as much as 2.5 tons—clash in fierce contests to secure breeding rights with the females.

“Most of these elephant seals return to their natal beach,” explained Stern. “While not every seal follows this pattern, the majority do, resulting in about 10,000 seals congregating at Año Nuevo annually.”

The history of elephant seals is marked by near extinction in the 1800s when they were extensively hunted for their blubber, used in oil production. By 1892, the population had dwindled to fewer than 100 individuals confined to a small island off Baja California’s coast.

In response to their perilous situation, the Mexican government enacted protective measures in 1922, quickly followed by similar actions in the United States. These efforts have been successful, with the Pacific’s elephant seal population now thriving at an estimated 250,000.

“There is a genetic bottleneck because they’re all coming from that same 30 to 60. But so far they’re doing really well, and we haven’t had any problems,” Stern said.

Año Nuevo State Park, about 90 minutes south of San Francisco, is one of the largest mainland breeding rookeries on the West Coast. During pupping season, visitors come in droves to book docent-led guided walks so they can watch the long-nosed bull seals clash on the shore, hear the barks and bellows filling the seaside air and see the mothers nurse sleek, 75-pound (34-kilogram) pups on the sand dunes.

“It’s awe-inspiring,” said Carrie Kahn, a visitor to the park from Berkeley, California. “And you just wonder, how do they move from point A to point B? They look like they’d be so slow. But they’re quick and big, and they’re honking and making noises.”

Male elephant seals have the highest level of testosterone of any mammal, Stern said. “So they want to mate, fight, eat, press repeat,” she said.

“You’re not at a museum. You’re not in an aquarium. You are right here watching them live doing what they do,” Stern said.

Between April and November, no tours are needed to visit the seals at Año Nuevo State Park. During pupping season, visitors must reserve a spot on a docent-guided walk to see the seals. Reservations can be made at www.reservecalifornia.com.