An alarming new reality is washing up on the shores of Cape Cod.
The waters may be getting too cold, too fast, for sea turtles to handle. As a result, conservationists are seeing wave after wave of the endangered animals wash up on Massachusetts' shores — apparently surprised by the sudden temperature shift.
"It looks like they're flash-frozen," Jenette Kerr of the Mass Audubon's Wellfleet Bay Wildlife Sanctuary tells MNN. "Their flippers are out. Their heads may be slightly raised. It looked like they were moving and then froze in place. They were like little cold bricks of ice. Holding one was like holding a chunk of ice."
Sea turtles, like all reptiles, are ectothermic — meaning they rely on outside sources to maintain body temperature. That's why you'll often see a snake basking in the sun. Or avoiding its glare altogether by slipping under the cool confines of a rock.
When external conditions get too frosty, reptiles can slow their metabolism to a crawl. In the case of sea turtles, extreme cold leads to their bodily systems shutting down completely and entering a "cold-stunned" state.
"It's something that's been occurring here for 20 to 25 years," Kerr explains. "It's just been gradually increasing to the point where we're now averaging about 400 cold stunned turtles every fall."
So far this season, volunteers have reeled in nearly 600 cold-stunned turtles from Cape Cod shores, the second highest number the sanctuary has ever seen. While many turtles are recovered alive and sent to medical facilities at the New England Aquarium, at least as many are found dead.
The most recent wave of castaways, 219 turtles in all, landed just a few days ago.
"We had a very unusual cold snap over Thanksgiving," Kerr says. "It was wind chills of single digits. Combined with cold temperatures and high winds, we had a lot of turtles come in. Most of them were dead."
Most concerning, the victims were almost entirely Kemp's ridleys.
The species is already critically endangered, having suffered massive losses due to human activity. Because of their very small size, Kemp's ridleys are especially vulnerable to temperature fluxes.
While scientists have yet to pinpoint what exactly is behind the cold-stunning epidemic, the default villain — climate change — is likely a factor here. Warming oceans tempt turtles to extend already-epic migrations farther north, where the tropical reptiles find a summer home well stocked with shellfish, sea urchins and shrimp.
"The water is warm enough these days that they can get along fine," Kerr says. "And then, unfortunately, what happens is as it cools off and they get cues to migrate south, some of them end up on the crook of the arm of the cape and they can't get out of the bay."