Data from: Heart rate reveals torpor at high body temperatures in lowland tropical free-tailed bats

Reduction in body temperature to meet ambient temperature is a common strategy for small endotherms to save energy. Daily heterothermy, or torpor, and its metabolic reduction is particularly pronounced in regions with large variation in daily ambient temperature, but many subtropical and tropical species also use daily heterothermy on cool days. This is particularly pronounced in temperate bat species (Order Chiroptera) , however, it is less clear how tropical bats save energy if ambient temperatures remain high. We recorded heart rate and body temperature of free-ranging Pallas’ mastiff bats (Molossus molossus) in Gamboa, Panamá, and showed that these individuals use low field metabolic rates across a wide range of body temperatures that conform to high ambient temperature. Importantly, low metabolic rates in controlled respirometry trials were best predicted by heart rate, and not body temperature. Molossus molossus enter torpor-like states at body temperatures of 32°C, and thermoconform across a range of temperatures. Such flexible strategies for energy savings may be far more common in tropical endotherms than currently known.