A massive sea lion nicknamed Chonkers is charming tourists and locals at San Francisco's Pier 39. On Thursday morning, visitors snapped photos of the Steller sea lion as he flopped on the pier among much smaller California sea lions. Chonkers is estimated to weigh between 1,500 and 2,000 pounds. He likely came from waters off Washington or Oregon. Laura Gill from The Marine Mammal Center says the pier offers protection from predators and plenty of food. Sea lions have gathered at the pier since after the 1989 Loma Prieta earthquake, becoming a tourist attraction.