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Revista chilena de historia natural

versión impresa ISSN 0716-078X

Resumen

CORTES, ARTURO; ROSENMANN, MARIO  y  BOZINOVIC, FRANCISCO. Cost-benefit relationship in thermoregulation of Chinchilla lanigera. Rev. chil. hist. nat. [online]. 2000, vol.73, n.2, pp. 351-357. ISSN 0716-078X.  http://dx.doi.org/10.4067/S0716-078X2000000200010.

Chinchilla lanigera, is an endemic rodent inhabiting desert areas of northern Chile. We postulated that wild chinchilla should has a cost-benefit relationship in thermoregulation to cope with desert habitats. We evaluated the energy metabolism in air and He-O2, evaporative water loss (EWL) and body temperature (Tb) at different ambient temperatures (Ta). The most relevant results indicated that the basal metabolic rate (BMR) was 0.66 mlO2/g h and a thermal conductance (C) of 0.0376 mlO2/g h°C; representing a 80.4% and 72.5% of expected values for eutherian mammals respectively. Thermal conductance in He-O2 was 0.089 mlO2/g h°C, being the ratio CHe-O2 /C = 0.089/0.038 equal to 2.34, the highest value recorded in rodents, indicating that C. lanigera exhibit the higher thermal insulation reported so far. Besides, the evaporative water loss (EWL) was a 95% of the expected value for heteromiyds. Chinchilla lanigera presents a clear cost-benefit relationships or trade-off in thermoregulation. In fact, the low C and EWL values implicate thermoregulatory costs at high temperatures (risk of hiperthermia), mainly when its desert habitats has temperatures ž 30°C. At the same time these low C, EWL and BMR values represent physiological benefits that allow energy and water economy in a xeric and unproductive habitat

Palabras llave : Chinchilla lanigera; basal metabolism; thermal conductance; evaporative water loss.

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