Nest-building in gray short-tailed opossums: temperature effects and sex differences.

The effects of ambient temperature and of sex on nest-building behavior were studied in a laboratory colony of gray short-tailed opossums, small, Brazilian marsupials. At 24 degrees C, both males and females used more nesting material and built larger nests of better quality than at 27 degrees C. Although both males and females built nests using the mouth, forelegs, hindlegs and tail, females built nests more reliably at the higher temperature and used more nesting material than males at both temperatures. These findings are discussed with respect to the thermoregulatory and reproductive characteristics of marsupials.