Abstract

Lagidium viscacia inhabits where water and food availability is low. We hypothesize that this rodent should minimize metabolic rate and water loss in order to cope with such extreme environments. We observed that Lagidium viscacia has (1) a comparatively lower basal metabolic rate (67%) and thermal conductance (78%) of predicted; (2) a higher pulmocutaneous evaporation rate which is 36% (mesic) and 63% (xeric); and (3) energetic cost of maintaining the water balance similar to that expected for rodents from xeric environments (2.8 cal/g h). In summary, Lagidium viscacia has physiological traits that favour energy and water economy to cope with such extreme habitats. © 2007 Elsevier Ltd. All rights reserved.