Centuries ago, river otters lived up and down the California coast, but after the fur trade wiped many of them out and development took over their habitat, their numbers dwindled. Once, they even lived in San Francisco, but until Sutro Sam showed up in October, no one had seen an otter in the city for at least three decades.

Sam lives in the Sutro Baths, the ruins of a once-privately owned swimming complex that are now part of the Golden Gate National Recreation Area. He swims, he sunbathes, he eats fish, he tolerates his many fans, he tweets. He’s a bona fide animal celebrity.

It’s not clear where he came from, the Los Angeles Times reports:

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The otter could have paddled across the mouth of San Francisco Bay from Marin County or hitched a ride as a stowaway in a boat, suggested Megan Isadore, co-founder of the River Otter Ecology Project, which tracks and studies the species in the area.

Nor is it clear how long he’ll stay — he might exhaust the area’s supply of fish or get lonely for other otters. But since his months at Sutro are being documented more thoroughly than the first months of a firstborn child’s life, at least there will be enough frickin’ adorable pictures to last us for ages.