Microhabitat Use by a Small Diurnal Rodent (Octodon degus) in a Semiarid Environment: Thermoregulatory Constraints or Predation Risk?

We examined the ways a small diurnal rodent, Octodon degus, copes with high environmental temperatures in a semiarid region in northcentral Chile. We hypothesized that degus are constrained in use of microhabitat by their limited tolerance to high environmental temperatures as well as by presence of predators. We recorded their activity from tracks on smoked tiles, under shrubs and in the open, and in large plots with predators either present or excluded. We monitored body temperature in the two microhabitats during warm and cool seasons. Our results support our hypothesis; degus chose covered areas even when predators were absent. We conclude that thermal restriction is a factor in determining use of space by degus.