Thermoregulation in the Angolan Free‐Tailed BatMops condylurus: A Small Mammal That Uses Hot Roosts

• Published in: Physiological and biochemical zoology 1999-07, Vol.72 (4), p.385-396
• Main Authors: Maloney, Shane K., Bronner, Gary N., Buffenstein, Rochelle
• Format: Article
• Language: English
• Subjects: Bats; Flow velocity; High temperature; Mammals; Metabolism; Mops; Thermogenesis; Thermoregulation; Torpor; Water loss
• ISSN: 1522-2152; 1537-5293
• DOI: 10.1086/316677

The Angolan free‐tailed bat (Mops condylurus) uses roosts that often exceed 40°C, an ambient temperature (T a) that is lethal to many microchiropterans. We measured the physiological responses of this species atT a's from 15° to 45°C. Torpor was commonly employed during the day at the lowerT a, but the bats generally remained euthermic at night, with a mean body temperature (T b) of 35.2°C. Metabolic rate reflected the pattern ofT b, increasing with fallingT aat night but decreasing during the day. Metabolic rate and evaporative losses were lower in torpid than in euthermic bats. Body temperature increased at eachT a>35°C and was 43°C atT aof 45°C. AtT aof 40°C bats increased dry thermal conductance and evaporative heat loss compared to lowerT a. At 45°C dry thermal conductance was lower than at 40°C and evaporative heat loss was 132% of metabolic heat production. At highT athere was only a slight increase in metabolic rate despite the employment of evaporative cooling mechanisms and an increase inT b. Collectively our results suggest thatM. condylurusis well suited to tolerate highT a, and this may enable it to exploit thermally challenging roost sites and to colonise habitats and exploit food sources where less stressful roosts are limiting.