Just as mysteriously as the sea lions came, the sea lions left.
For the past two decades, sea lions have staked out the docks at San Francisco's Pier 39 as a daily hangout. At one point over 1,500 of them called the docks their home and at least some would stick around through the winter.
But now they're all gone.
Officials at San Francisco's Marine Mammal Center aren't officially worried, but no one has any idea where they might be.
Alexis Madrigal has the whole story over at Wired; swing over and give it a read.
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