California ? He has flippers instead of feet – and certainly no sneakers or hiking boots. But that didn’t stop a sea lion from joining schoolchildren on a walk-a-thon.

The marine mammal apparently noticed children doing laps Friday morning around a course they had set up at the Marin Country Day School next to the shores of the San Francisco Bay. The 185-pound Steller sea lion waddled ashore, shocking students and teachers.

“He did a whole lap,” said Kelly Watson, director of constituent relations and web communications at the private school.

It was the latest brush with humans for the 1-year-old sea lion, called Astro by staffers at the Marin Headlands-based Marine Mammal Center.

Astro’s mother abandoned him at Ano Nuevo Island off the San Mateo coast in June, prompting biologists to bottle-feed the pup. They released the adolescent on April 25 with a radio tag.