Assessing responses to heat in a range-shifting, nocturnal, flying squirrel

Area of Science:

• Zoology
• Physiology
• Ecology

Background:

• North American flying squirrels exhibit northward range shifts.
• Warming winters are studied, but summer temperature effects on flying squirrels are unexplored.

Purpose of the Study:

• Investigate high environmental temperatures' effects on flying squirrel thermoregulation and energetics.
• Determine if rising summer temperatures influence flying squirrel range shifts.

Main Methods:

• Used flow-through respirometry to measure metabolic rate and water loss at high temperatures.
• Employed temperature-sensitive data loggers to record free-ranging body temperatures.
• Focused on Southern Flying Squirrels (Glaucomys volans) in North America.

Main Results:

• No significant metabolic rate increase up to 40 °C.
• Evaporative water loss increased above 36.2 °C.
• Body temperature showed circadian patterns and slight increases with higher ambient temperatures, without significant energetic cost.

Conclusions:

• High ambient temperatures unlikely to cause energetic strain for Southern Flying Squirrels.
• Thermal tolerance suggests summer heat may not directly limit G. volans.
• Rising summer temperatures could still impact northern species (Glaucomys sabrinus) and influence North American flying squirrel distributions.