Meeting Abstract
Desert environments challenge animals by exposing them to extreme heat while simultaneously providing little water. When exposed to environmental temperatures above body temperature, rodents rely on evaporative cooling as means for dissipating excess heat. However, the high water requirements associated with evaporative cooling produce a physiological trade-off between conserving water to maintain hydration and using water to cool evaporatively. For many desert rodents, we lack a complete understanding of the thermoregulatory strategies in the heat, especially the simultaneous responses in evaporative cooling, metabolic heat production, and body temperature variation. We examined seasonal and geographic variation in thermoregulatory strategies of four species of Cricetid rodents to understand physiological response to local climatic variables. We used flow-through respirometry to measure evaporative water loss, metabolic heat production, and body temperature as a function of ambient temperature. Our research focused on Neotoma albigula, N. lepida, Peromyscus eremicus, and P. crintus at four sites with elevations ranging from 300-1600m in the Mojave Desert. We found interspecific differences in the use of hyperthermia as a strategy to conserve water, and in general, thermoregulatory strategies appeared to focus on water conservation during the summer during periods of extreme heat and water scarcity. Moreover, thermoregulatory strategies also depended on recent exposure to local temperature, humidity, and precipitation patterns. Understanding physiological responses to local climate variability will improve predictions for forecasting the physiological impact of climate change.
