Thermoregulatory development in pups of Ctenomys talarum (Rodentia; Ctenomyidae).

ANA PAULA CUTRERA; DANIEL ANTINUCHI; CRISTINA BUSCH

PHYSIOLOGY AND BEHAVIOR

Elsevier Science

Lugar: San Diego; Año: 2003 vol. 79 p. 321 - 330

0031-9384

The effect of the mother’s contact and huddling with nest mates on the mass-specific metabolic rate (RMR) and body temperature (Tb) of pups of Ctenomys talarum from 2 to 45 days of age was evaluated at ambient temperatures (Ta) within and below the adult thermoneutrality range (25 and 19 ºC, respectively, the latter corresponding to the one recorded in burrows during the spring, when pups are born). Under these conditions, we recorded the percentage of time that pups spent huddled with nest mates, with their mother and suckling. At 19 ºC, huddling and contact with the mother significantly reduced pups’ body heat loss until they were 15 days old but did not affect their RMR. Fifteen-day-old pups showed an increase in their RMR, associated with the onset of independent thermoregulation. Pups older than 15 days showed a less variable Tb and their RMR decreased. 2- to 30-day-old pups spent 80% of the time in contact with their mother and, when she was absent, they spent 70% of the time huddled with their nest mates. However, these results did not differ between the two Ta evaluated. Forty-five-day-old pups reached adult Tb and spent significantly less time in contact with their mother and nest mates. Huddling did not have a significant effect on energy expenditure of young tuco-tucos, being this related to the stable thermal conditions found in natural burrows and pups’ mode of development.