North American Quaternary cold-tolerant turtles: distributional adaptations and constraints

The painted turtle, Chrysemys picta , and the snapping turtle, Chelydra serpentina , occur in aquatic habitats north of Lake Superior in boreal forest and cold prairie areas across Canada, and have by far the most northern range of any modern North American chelonian taxa. These two species are also the dominant turtles of the North American Pleistocene glacial ages and were among the first species to invade formerly glaciated areas at the end of the Wisconsinan. These Pleistocene occurrences are documented here. Several remarkable behavioral, physiological and reproductive adaptations that may act together to allow these species to survive in such northern areas are discussed.