Meeting Abstract
Acclimatory responses to low temperatures have been characterized in many small mammal species. For example, when housed at temperatures of 5-10°C for several weeks, small rodents typically show increases in both basal and maximal aerobic metabolic rates, as well as associated morphological changes (e.g., increases in the mass and activity of brown adipose tissue). However, relatively few studies have examined whether cold acclimation alters locomotor performance or behavior that involves exercise abilities. As part of research on the energetic and immune consequences of fatherhood, we are interested in these possibilities in male California mice. Here, we tested the hypothesis that cold acclimation would alter morphological, physiological, metabolic, performance, and behavioral traits (e.g., body mass, total fat, muscle mass, hematocrit, grip strength, resting metabolic rate, maximum oxygen consumption (VO2max) during forced exercise, maximum sprinting speed, and predatory aggression). Adult male California mice were weighed daily and housed in groups of 3-4 at room temperature (23°C, n=65), 10°C (n=48) or 5°C (n=25) for 2-4 weeks, then underwent a 7-day testing regimen. Neither body mass nor sprint speed differed statistically among housing conditions. However, mice housed at 5°C had higher mass-adjusted VO2max than those housed at room temperature (p<0.05), confirming results for other species of Peromyscus. This work was supported by NSF IOS-1256572 and NIH HD075021.
