Environmental modification of nest-building in the white-footed mouse, Peromyscus leucopus

Exposure of Peromyscus leucopus to low ambient temperature (5°C versus 26°C) during a 5-day test resulted in the building of larger nests. The weight of cotton used by the animal was employed as an index of nest size. Animals which had been acclimated to 5°C for 6 weeks prior to testing built larger nests at 5°C and smaller nests at 26°C than did warm-acclimated mice. In addition, warmacclimated P. leucopus maintained for 6 weeks under short photoperiod (LD9:15; L=light, D=dark) built larger nests at both 5°C and 26°C than did animals maintained under long photoperiod (LD 16:8). This pattern of response to environmental conditions approximating winter (low ambient temperature, short photoperiod) indicates that nesting is a component of the physiological-behavioural complex of cold adaptation.