Preliminary data on water metabolism of Phyllotis xanthopygus

KOCH, E.; CAVIEDES VIDAL; ALMEIDA C.; ZULETA C; CAVIEDES CODELIA

Mendoza, Argentina

Congreso; XVII Reunión Científica; 1999

Sociedad de Biología de Cuyo

P. xanthopygus is a sigmodontine rodent dwelling on both sides of the Andes, from NE Argentina and central Chile to Santa Cruz (Argentina) in the South. The rodent may have developed strategies to cope with differences in water availability among areas. Several mechanisms could be involved, e.g. physiological, morphological and behavioral. Data on evaporative water loss (EWL) rate of P. xanthopygus (n=5) captured in Uspallata (Mendoza, Argentina) are presented. EWL was gravimetrically assessed at 10, 20, 30, 35 and 40 °C ambient temperatures. Values are mean ± SD. Minimum EWL 2.41 ± 0.58 mg H2O/(g.h); body mass 62.41 ± 5.46 g; body temperature 38.5 ± 0.7 °C. Minimum EWL was 25.5% higher than that predicted by the allometric equation for a typical mesic rodent. Behavioral mechanisms are to be expected in P. xanthopygus when dwelling xeric environments, since their hight evaporative levels are not compatible with survival in water restricted environment.