Meeting Abstract
Increasing temperatures have the potential to rapidly alter species’ range distributions and subsequent interactions. In North America, both species of flying squirrel (Glaucomys volans and G. sabrinus) have already undergone significant northward range shifts over the past 25 years. Previous studies point to higher winter temperatures as the driver and so, largely focused on the effects of cold temperatures on thermal physiology. We are interested in the other piece of the puzzle – the effects of high ambient temperatures on the thermophysiology of the only genus of nocturnal tree squirrels in North America. We measured resting metabolic rate and subcutaneous body temperature of southern flying squirrels, at the leading edge of their northern expansion, across a range of ambient temperatures, with a particular focus on temperatures above 30°C. We also measured free-ranging, core body temperature of southern flying squirrels and American red squirrels (Tamiasciurus hudsonicus) during late summer/early fall. Free-ranging, core temperature data is virtually non-existent for North American flying squirrels and can provide insight into the suite of thermoregulatory characteristics that may aid or hinder northward expansion. The diurnal American red squirrels occupy a similar ecological niche, but different temporal niche, as the nocturnal flying squirrels. The diurnal/nocturnal comparison between flying squirrels and red squirrels offers another opportunity for uncovering thermal physiological drivers of geographic distributions and range shifts in small mammals.
