Volunteers coaxed eight beached whales back to sea and took two to an aquarium, but 45 others grounded near the Kennedy family compound were given up for dead or put to death overnight to end their misery.
Rescuers on Cape Cod had struggled most of the day Tuesday to save the pilot whales, splashing them with water and soothing them with wet towels as the giant mammals - most of them mothers and calves - lay listlessly, making squeaking and whistling noises and occasionally twitching."I'm offering a little comfort," said volunteer Karen Kelly. "They respond to your touch and your voice. They are scared and they don't know what's going on.
"Say a prayer," she added.
When the weakened whales began foundering in seaside pools filled by the rising tide and could no longer keep their blow holes above water and avoid drowning, more than a dozen were put to death with lethal chemicals.
The volunteers were sent home around midnight, expecting all the whales to be dead by morning.
Experts were unable to explain why the whales beached themselves. The animals were 6 to 15 feet long and many weighed more than a ton.
About 100 volunteers had endured high wind and freezing temperatures in the effort to save the animals. Working with the help of floodlights and headlights, they used stretchers to return some of them to open water.
One rescued whale later washed ashore and was destroyed. Eight others were tracked by boat for more than a mile.
Radio transmitters were placed on two of the rescued whales and their fins were fitted with glow-in-the-dark tags, but their ultimate fate remained unknown. Whales pushed back into the water often beach themselves again.
"It's like a person being in a real bad car accident, and then telling them to go drive again," said Colleen Crogan, a National Marine Fisheries Service official.