Bats Biodiversity Climate change

Heat tolerance of female Yuma Myotis (Myotis yumanensis) in the hottest part of their Canadian range

K de Mel, R., Brigham, RM., Baloun, D., Lausen, C., Cangemi, T., Watters, T., Gandy, B., Freeman, M., Probert, A. & Czenze, Z.

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Key points

• Bats face challenges when it comes to avoiding overheating – evaporative water loss can dump heat, but small-bodied bats hidden in small roosts during the heat of the day have limited body water to lose and may not be able to dissipate enough heat through evaporative cooling.
• Research in the hottest part of the species' range (Lillooet, BC) found the bats could tolerate temperatures up to about 44°C in dry conditions by letting their body temperature rise rather than using their body’s precious limited water stores to cool themselves.
• However, these bats typically roost with many other individuals, each with some evaporative water loss, causing the roost air to be moist. In moist air, evaporative cooling does not allow bats to effectively dump heat, thus the heat that bats can tolerate will be lower.
• Caution is needed to ensure that artificial roosts are designed with different temperature options or zones so bats can move to cooler areas during extreme heat.

Recommended citation

K de Mel, R., Brigham, RM., Baloun, D., Lausen, C., Cangemi, T., Watters, T., Gandy, B., Freeman, M., Probert, A. & Czenze, Z. (2026). Heat tolerance of female Yuma Myotis (Myotis yumanensis) in the hottest part of their Canadian range. Journal of Mammalogy. https://doi.org/10.1093/jmammal/gyag070