Nature is weird.

Sea lions at Pier 39, before the exodus
Twenty years ago, hundreds of sea lions showed up at Pier 39 in the Embarcadero area of San Francisco, where they quickly became a fixture and a tourist attraction. Millions of tourists (me included) stopped to watch them splashing around, barking, flopping onto the flat rectangular wooden docks floating at the pier, and dozing in the sunshine. Then, suddenly, a month ago they were gone, and no one knew where they went or why they left. All kinds of theories were offered — including one suggesting that the sea lions, using some kind of aquatic ESP, had sensed an imminent earthquake and hit the road.
It turns out that reality is a bit less sensational. Sightings of sea lions up in Oregon have caused scientists to conclude that the sea lion colony has migrated north up the Pacific coast in search of food. I expect that we will soon be seeing stories about how what happened to the food supply in the San Francisco Bay and whether there is another explanation for the sea lions’ unexpected departure. In the meantime, I imagine that the tourist-dependent businesses near Pier 39 will be fervently hoping that the frolicking sea lions will quickly return. Pier 39 just won’t be the same without them.