Scientists trying to determine what killed a blue whale that washed onto Fort Funston Beach have been stymied in their research efforts by sharks that devoured the 80-ton mammal's vital organs.

"It appears that sharks entered the chest cavity and ate the heart and lungs" after the whale died but before it drifted ashore, Ray Deiter, a veterinarian with the Coast-watch Wildlife Society said Sunday."It still appears it died of natural causes," said Deiter. "I feel good that we did not find any external marks that would indicate it (the whale's death) was caused by man," he said.

Four workers spent the weekend carving the whale into sections and dragging the pieces behind a bulldozer. About 60 tons will be taken to a Daly City landfill and the bones will be buried in the sand, Coast-watch director Marian Barnes said Sunday.

"We'll exhume the bones in five years or so and have a beautiful whale skeleton to display," Barnes added.

A large audience watched Sunday's proceedings but a strong stench kept them at a distance.