BOSTON -- A leatherback turtle washed up on a Cape Cod beach Thursday.

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The turtle, estimated to weigh about 400 to 500 pounds, was found on Popponesset Beach in Mashpee. Officials at New England Aquarium said that the turtle is dead and had been injured.

"We think what happened was that it was hit by a boat and it washed up with the current and wind," said University of New Hampshire marine biologist Kara Dodge.

With beachgoers watching and listening to her impromptu lesson, she took samples from some of the turtle's tissues and organs for research.

"It was a male, which is exciting because once they leave the nesting beaches as baby turtles they're never seen again. They spend their entire lives at sea," she said.

"It was cool -- really big. I've never seen anything like it. And I thought it came from the Galapagos Islands," said Eleanor Kharasch, of Mashpee.

In one year, a leatherback can travel from the Caribbean to New England and across the Atlantic. They're usually in the Cape Cod area from May to October, and biologists said they come close to shore to feed on jellyfish.