There are more than two dozen pens at the Marine Mammal Care Center in San Pedro, Calif., and no vacancy. They're filled with more than a hundred sea lion pups, grouped by health condition.
The pups in the first row of pens are swimming in small pools and sliding across the wet concrete.
"These guys on this half of the facility are actually doing pretty well," says Lauren Palmer, the chief biologist at the center. "They're eating on their own. They're playing. They're porpoising."