Meeting Abstract
As the earth’s ambient temperature continues to rise, it is important to understand the relationship between animal metabolism and changing global climates. Thermophysiology is therefore becoming increasingly important in helping to determine how a species will respond to climate change. Surprisingly little, however, is known about thermoregulation of tropical endotherms. To increase our knowledge of the physiology and energetics of tropical mammals, we measured the resting metabolic rate (via oxygen consumption) of free-ranging lesser treeshrews (Tupaia minor, order Scandentia) at varying ambient temperatures. Basal metabolic rate was on average 1.26 mL O2.hr-1.g-1, which is within the range predicted for a 65g animal. However, the treeshrews had a surprisingly large (~10°) thermoneutral zone when compared to other species of similar body mass. We calculated a lower critical temperature of 27.3° but could not determine the upper critical temperature using metabolic rates even at temperatures as high as 36°. The treeshrews maintained a large gradient between body temperature (>37° at rest) and the ambient temperatures measured, which were representative of what the species experiences in its environment. Because of this substantial gradient and the species’ large thermal neutral zone, we posit that the species will be able to cope with predicted increases in local ambient temperatures. This is in contrast to most tropical ectotherms that are generally predicted to be more vulnerable to changes in climate than their temperate counterparts, and highlights the importance of further research in the tropics.
