San Francisco's Fisherman's Wharf is known for its cheesy gift shops, snazzy street performers, clam chowder served in their world famous sourdough bread bowl and . . . . hundreds of loud and boisterous sea lions that reside on the docks of its Pier 39.

However, after entertaining tourists and locals for nearly 20 years, the mammals have suddenly vanished and, nobody knows why they left or where they went.

The first sea lion made his appearance at the pier in 1989, shortly after the 7.0 magnitude Loma Prieta Earthquake, and promptly took over entire dock. Others soon followed and suddenly there were so many, that the aging docks collapsed under their weight.

At first the officials at Pier 39 were not sure how to handle these smelly mammals with their loud 'dog-like' barks, which were starting to take over the every available space including private boats moored at the Pier. However, they soon became such a tourist draw that the officials decided to move the private boats elsewhere, and build new docks for their uninvited guests, who seemed to have any intention of leaving.

Over the years, while the jostling mammals have never gained the affections of the fishermen for obvious reasons, the rest of the city has embraced them with open arms.

While even the experts at the Marine Mammal Center are not sure why the sea lions have upped and left, they are not worried. They believe it is probably due to the lack of food supplies, which have been too far away from the north coast or too deep, causing many young seals to starve. In fact, the Center has had to rescue a record number of young mammals who were unable to fend for themselves this year.

Meanwhile, the folks at Pier 39 are in a bit of a quandary. They were all set to celebrate the mammals 20th anniversary with a 'Sea-Lebrities' party on January 15th. Now, with the stars missing, they may have to re-consider the whole event. Hopefully, the sea lions will see the invite (or this article) and show up!

sources: yahoonews.com,latimes.com,bbcnews.com