CORTE MADERA, Calif. -- He has flippers instead of feet and certainly no sneakers or hiking boots. But that didn't stop a very determined sea lion from joining schoolchildren on a walk Friday in Corte Madera.

The 185-pound sea lion waddled ashore at Marin Country Day School, near San Francisco Bay, where he completed a full lap of a walk-a-thon.

Staffers at the nearby Marine Mammal Center call the 1-year-old sea lion Astro. He was abandoned in June and bottle-fed by biologists, who released him April 25 with a radio tag.

Astro swum with elephant seals between Point Reyes and the Farallon Islands but keeps returning to shore.

Nearly a week ago, he swam back to Corte Madera, where biologists picked him up and released him in the Farallons.

He returned again Friday in time for the walk-a-thon.

The Marine Mammal Center will try to find him a permanent home, possibly the Mystic Aquarium in Connecticut, which keeps threatened Steller sea lions.