Meeting Abstract

P3.210  Tuesday, Jan. 6  Life in an extreme environment: The effects of heat on foraging and survival of woodrats (Neotoma) in Death Valley, California MURRAY, I.W.*; SMITH, F.A.; Univ. of New Mexico, Albuquerque; Univ. of New Mexico, Albuquerque imurray@unm.edu

Death Valley, CA is one of the hottest and driest environments on Earth, with summer temperatures routinely exceeding 50°C. Living in such extreme thermal conditions undoubtedly poses unique selective pressures on organisms, yet a number of vertebrate species are found in the hottest habitats at -84m below sea level. One of these is the Desert woodrat (Neotoma lepida), a small (80-200g), herbivorous murid rodent that occurs in remarkably high densities on these sites. The presence of this animal is particularly surprising because it lacks any sort of specialized adaptation to heat, and moreover, has a lethal upper critical temperature of 42°C. Here, we report on studies examining how these woodrats survive and prosper in a habitat where ambient temperatures regularly exceed lethal maximums (42°C) for weeks at a time. By using small temperature data-loggers (Thermochron iButtons) attached to rat collars, we characterize the daily activity budget and foraging ecology of these animals in the context of the thermal environment. We find that: 1) movement patterns are tightly constrained by temperature, 2) animals regulate movement to minimize exposure to potential lethal temperatures, and 3) there are seasonal patterns to foraging behavior. We gain important insights into cryptic components of woodrat biology with the aid of iButtons.