(ABC News)

ABC News' Katie Kindelan and Candace Smith report:

A giant sea turtle that has been described as "like a swimming dinosaur" has been released back into the waters this weekend after it was rescued from a mud flat near the tip of Cape Cod, according to New England Aquarium officials.

The 7-foot-long, 655-pound black male leatherback turtle, an endangered species, was treated with "drugs to stabilize its blood values and oxygen levels," The Associated Press reported.

The turtle was found late Wednesday night on a mud flat in Pamet Harbor, near the town of Truro, Mass., by staff from a local Audubon sanctuary.

Due to darkness and the remote location, the staff had to leave the turtle until Thursday morning. Then they had to rely on a team of volunteers and a transport cart normally used to carry stranded dolphins to hoist the turtle onto a vehicle to take it to the Aquarium's marine animal care center.

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Aquarium spokesman Tony LaCasse described the turtle as "near death" when he arrived at the aquarium. One of its massive flippers had been partly severed, likely the result of some sort of predatory attack or a run-in with a boat, according to LaCasse.

The straight line of damaged tissue on the flipper points to a possible entanglement in a vertical line in the water, perhaps from a lobster pot or a boat mooring. Nearly 20 leatherbacks have died in New England waters this season from such accidents, according to the aquarium.

The injury to the turtle's left flipper affected its ability to forage for food and could have led to an infection.

A leatherback rescue is rare because the animals are open-ocean turtles and cannot be kept in captivity. Even at 655 pounds, the turtle is considered skinny in comparison to its fellow leatherbacks, which typically weigh around 1,000 pounds, according to LaCasse.

Leatherbacks flock to Cape Cod and surrounding islands each June to feed on the jellyfish that are abundant in the waters. They migrate south for the winter beginning this month and into October, according to the aquarium.

The Associated Press contributed to this report.