Why do pilot whales beach themselves?

Scientists are unable to pinpoint the reason why.  Some think that  pilot whales move in close-knit family groups and when one of the family members become beached by accident or intentionally,  the others don't leave the beached member and that results in almost the entire pilot family dying for the sake of one from their group.



From USAToday
With 10 whales already dead, rescuers hope to coax the remaining pilot whales back into deeper waters.
Thirty-five of the 51 pilot whales stranded off Everglades National Park began a slow return to deeper waters Thursday afternoon, giving scientists new hope in a grim situation.

Rescuers from agencies including the National Park Service and the Coast Guard positioned their boats to corral the whales and used sound vibrations from aluminum pipes to drive them away from the shore, said Blair Mase, coordinator of the National Oceanic and Atmospheric Administration's marine mammal stranding network.
Using these "gentle herding" techniques, scientists were able to get the 35 whales into 18-foot-deep water about 6 miles offshore. Happy with the progress, most of the rescuers returned to shore midafternoon Thursday.
"We are cautiously optimistic," Mase said. "Even though we are hopeful, this situation can go either way."
Of the 51 whales initially discovered stranded at Highland Beach on Tuesday morning, 11 are dead. Five that have not been located may have died and sunk to the ocean floor, she said.
Pilot whales usually swim in waters 1,000 feet deep about 15 miles offshore, but Mase said she would be satisfied once the whales moved into water 100 feet deep. If they stay on their path Friday, officials will call off the rescue mission, she said...........