group of sea lions sit on a dock at Pier 39 in San Francisco

Tourists look on as a group of sea lions sit on a dock at Pier 39 in San Francisco 12 December 2007. The sea lions took over Dock K at Pier 39 in January 1990 and have been residents of the dock ever since. The boisterous and playful mammals are a huge hit with tourists and at times during the winter season the population can grow to 900