Hunger and contamination may be key factors behind this unusual behaviorSea lions are one of the main attractions for those who visit the west American coast. But public interpretation of these marine animals might be very far from reality. Even healthy sea lions are best left alone, because at its 300 kg (800 pounds), a male armed with sharp pointed teeth is a formidable beast, but a 100 kg female also could inflict a lot of damage.
Usually, sea lions bite only if they feel threatened or cornered; otherwise, they will rather seek an escape route. But the last months' series of sea-lion attacks on people has triggered the alarm calls of the officials and experts, as these animals are not the cute and cuddly circus pets. "People should understand these animals are out there not to attack people or humans. But they're out there to survive for themselves," said Jim Oswald, a spokesman for the Marine Mammal Center, San Francisco.
In the last month, a very aggressive sea lion bit 14 swimmers and chased 10 more out of the water at San Francisco's Aquatic Park, a sheltered lagoon near the bay, with one victim suffering puncture wounds. In Southern California in June, a sea lion attacked several people on Manhattan Beach and bit a man before waddling into the water and swimming away.
Last spring, a sea lion attacked a woman in Berkeley, slashing out a chunk of her leg. Last year, several sea lions took over a Newport Beach marina and sank a vintage 15 m (50 feet) yacht. A lifeguard in Santa Barbara was bitten three times while swimming off El Capitan State Beach.
Compared to this high incidence of sea lion attack, less than 10 people have been attacked by sharks off the California coast since 2000, but two were fatal. In Alaska, a huge male jumped onto a fisherman's boat in 2004, knocked him overboard and pulled him underwater; miraculously he escaped without severe injury. Experts have described the most recent attacks as abnormal behavior.
Still, with a growing population about 200,000, these social creatures are increasingly likely to encroach with humans. "Sea lions accustomed to the easy pickings of seafood scraps in popular fishing areas can become aggressive toward people if they fear their food is about to be taken away," said Oswald, which is likely to have happened at the Berkeley marina where fishermen dock their boats and feed fish scraps to sea lions. When the scraps run out, sea lions can turn aggressive and this way the woman - a crew member - got bitten. "A food shortage off the Southern California coast could be driving more hungry sea lions than usual to San Francisco Bay", said Lynn Cullivan, a spokesman for San Francisco Maritime National Historical Park.
Another factor blamed to be behind the unusual behavior of the sea lions is toxic algae bloom, provoked by agricultural runoff and other pollution, that can intoxicate marine fauna by domoic acid, harmful for the brain.
The Marine Mammal Center took care of more than 200 sea lions intoxicated with domoic acid last year. "Veterinarians at the center believe the brain damage caused by the poison could have led to the marauding animal's erratic behavior in Aquatic Park, Oswald said, though they cannot be sure without actually examining the sea lion".
"People who swim with the lions - though I'm sure that's nice - it's probably not the best thing to do," Oswald said. "It's a wild animal. And you want to keep them wild."