The relationship between food intake, body fat and reproductive inhibition in prairie deermice (Peromyscus maniculatus bardii).

1. Reproductively-inhibited deermice selected from four laboratory populations consumed significantly less food than reproductively-proven pairs. 2. Reproductively-inhibited animals predominantly, but not consistently, had reduced total body fat compared with reproductively capable deermice. 3. The per capita food consumption rate of two populations followed for 26 weeks since founding, decreased over time to about 65% of the daily intake of the proven animals used to found the populations. 4. An aggregation or "huddling" behaviour with concomitant reduction in thyroid hormone activity, possibly in response to the density of the "huddle", is suggested as an explanation for these observations.