Keeping your cool: thermoregulatory performance and plasticity in desert cricetid rodents

• DOI: 10.1242/jeb.243131
• Publication Date: 2022-02-08T10:15:38Z
• Authors: Richard W. Ramirez; Eric A. Riddell; Steven R. Beissinger; Blair O. Wolf
• Keywords: Evaporative cooler; Torpor

Small mammals in hot deserts often avoid heat via nocturnality and fossoriality, are thought to have a limited capacity dissipate using evaporative cooling. Research date has focused on thermoregulatory responses air temperatures (Ta) below body temperature (Tb). Consequently, the performance of small exposed high Ta is poorly understood, particularly across geographic seasonal scales. We quantified four cricetid rodents (Neotoma albigula, Neotoma lepida, Peromyscus eremicus, crinitus) Ta, at sites Mojave Desert. measured metabolism, water loss Tb flow-through respirometry. When Ta≥Tb, showed steep increases Tb, copious salivation dissipation. Most individuals were only capable maintaining Ta-Tb gradients ∼1°, resulting tolerance limits (HTLs) range Ta=43-45°C. All species exhibited thermoneutral ∼35-36°C, increased maximal levels ∼43°C. Metabolic rates steeply all as approached Tb. also observed significant resting metabolism from summer winter within above zone. In contrast, we found few differences sites. Our results suggest that physiological cope with environmental exceed rapidly warming environment may increasingly constrain their nocturnal activity.