Wildlife experts and law enforcement officials are working to keep a determined elephant seal off a Northern California highway that it has repeatedly tried to cross, slowing traffic in the area.

California Highway Patrol spokesman Officer Andrew Barclay says callers first reported the 500-pound mammal was trying to climb the divider wall of Highway 37 near Sears Point in Sonoma.

He says U.S. Fish and Wildlife Service crews and CHP officers managed to usher the adult seal back into the San Francisco Bay. But instead of swimming away, the animal got back on land at least twice.

Barclay says crews with the Sausalito-based Marine Mammal Center and the San Pablo Bay National Marine Sanctuary are also helping with the rescue.

Marine Mammal Center spokeswoman Laura Sherr says the seal doesn't seem hurt.