On a frigid April day, Brock University Professor of Biological Sciences Glenn Tattersall, then-PhD student Danilo Giacometti and wildlife researcher Patrick Moldowan ventured out into Ontario\u2019s Algonquin Provincial Park hoping to take in a rare sight.<\/p>\n
Their efforts paid off as they watched several blue-spotted salamanders crawl across snow and ice \u2014 a curious move for amphibians known for being \u201cfreeze intolerant\u201d\u00a0and avoiding the extreme cold.<\/p>\n
Freeze tolerant amphibians, on the other hand, can survive being up to 70 per cent frozen during the coldest winter weather, Tattersall says, and safely thaw when temperatures rise. This is because glucose and glycerol in their system acts as an \u201cantifreeze\u201d and protects their internal organs by keeping their tissues from freezing completely.<\/p>\n
\u201cBut the blue-spotted salamander can\u2019t survive being frozen in that same way,\u201d he says. \u201cWe expected they would avoid physical contact with ice crystals to minimize the risk of freezing, so it seemed\u00a0kind of funny\u00a0that\u00a0they would take that risk.\u201d<\/p>\n
Native to North America, blue-spotted salamanders are found in the Great Lakes region and other parts of Ontario, Quebec and the northeastern U.S.<\/p>\n
They live in underground burrows below the frost line during winter and emerge to breed in nearby bodies of water in the spring. While they may encounter snow and ice along the way, Tattersall says it was commonly believed that sunshine and warmer air temperatures would offer them protection against freezing.<\/p>\n
Much of the previous research on how the salamander\u2019s body reacts to cold temperatures has been conducted in labs. To find out more about the amphibian\u2019s thermal biology in a natural setting, the researchers collected a variety of measurements from blue-spotted salamanders migrating to Bat Lake in Algonquin Provincial Park.<\/p>\n
Using a specialized camera, they captured thermal images of the salamanders, recorded their body mass and determined their sex, as well as measuring air temperature and humidity.<\/p>\n
The results showed that blue-spotted salamanders can partially overcome the risk of freezing through \u201csupercooling,\u201d a process in which the animal\u2019s bodily fluids are able to drop below 0 degrees C without freezing.<\/p>\n
Tattersall says the study is an initial step toward understanding how being in a supercooled state can help blue-spotted salamanders ensure their survival.<\/p>\n
He says this ability gives blue-spotted salamanders a competitive advantage over other animals breeding in the spring. By being among the first to arrive at water sources, the salamanders are able to lengthen their breeding season, avoid predators and create more opportunities for their offspring to grow.<\/p>\n