Fig. 4.

Examples of how the ambient temperature of the vivarium affects the quality of a nest built from cotton nestlets. Nests at 22 and 30 °C are relatively well constructed and mice are essentially protected beneath the cotton. At 32 °C the nest is not as intricate and there is a larger opening. At 34 °C, the nestlets are shredded but not nest is built, suggesting a marked effect of heat stress. Core temperatures of these mice presented in Fig. 2A,B. Gordon (unpublished).