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In ancient times, people had some wild beliefs about salamanders. They thought these cool-skinned amphibians could survive in fire. That is not true, of course. But some salamanders do have a surprising ability to deal with freezing cold. NPR's Nell Greenfieldboyce reports on what scientists recently saw when they came across some blue-spotted salamanders.
NELL GREENFIELDBOYCE, BYLINE: Blue-spotted salamanders live up to their name. They're black with shimmery blue spots. They're found in the northern part of the country, across the Great Lakes region and New England, up into Canada. So winters are cold. And the blue-spotted salamanders spend the winters underground.
DANILO GIACOMETTI: They are moist-skinned animals, so they typically avoid freezing conditions, so they avoid ice.
GREENFIELDBOYCE: Danilo Giacometti is a researcher who's now at the University of Sao Paulo in Brazil. He studied these critters while doing his Ph.D. work in Canada. He says, not too long ago, he and some colleagues were out near a lake in Ontario in the late winter.
GIACOMETTI: And we noticed that, OK, so there's still ice on the ground. The lake is still frozen. But for some weird reason, there were blue-spotted salamanders on land.
GREENFIELDBOYCE: These nocturnal salamanders had left their burrows in the forest. They were migrating towards the lake, where they breed. Biologist Glenn Tattersall of Brock University was on the research team. He says it's been known for a while that blue-spotted salamanders can occasionally be seen walking on snow. But it was thought this happened when temperatures had actually warmed up a bit.
GLENN TATTERSALL: You know, the presumption that we had was that maybe they're moving over snow while the temperatures are just close to freezing.
GREENFIELDBOYCE: When they saw these salamanders, the researchers had a thermal camera with them. So they used it to take thermal images that let them measure the body temperature of the animals. Surprisingly, what they found is that some salamanders actually had body temperatures as low as 25 degrees Fahrenheit, well below freezing. And yet they were crawling around.
TATTERSALL: If the animal was a frozen icicle, it probably wouldn't be capable of movement.
GREENFIELDBOYCE: These salamanders apparently have some kind of natural antifreeze that allows them to be chilled below the normal freezing point of body fluids. Scientists call this being supercooled. Don Larson is with the University of Alaska Fairbanks. He wasn't part of this research team, which published its findings in the Canadian Journal of Zoology.
DON LARSON: The really cool thing about what they saw was that they showed that there's activity in the supercooled state. Even though they have this very low body temperature, they're still able to do things.
GREENFIELDBOYCE: He says this probably helps these salamanders by letting them start their breeding as early as possible while maybe avoiding predators that are still hunkered down. He says amphibians can be surprisingly adept at dealing with frigid temperatures. He studies the Alaskan wood frog, which can freeze solid for months. Its heart stops completely. And in Russia, there's two species of Siberian salamanders...
LARSON: That we know can survive down to negative 40 or colder. And Celsius or Fahrenheit, negative 40 is about the same.
GREENFIELDBOYCE: But he says, compared to all the research that's been done on what birds and mammals do in the winter, scientists know remarkably little about how cold-blooded amphibians get by.
Nell Greenfieldboyce, NPR News.
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