Fig. 2. Relationship between resting metabolic rate (RMR) and body mass prior to breeding (filled circles) and at peak lactation (open circles) of females with unmanipulated (A) and manipulated (B) litters. Least-squares regression lines fitted to the two sets of data are shown and are described by (A) y=0.79x+0.1 (F_1,69=5.4, P=0.023) prior to breeding and y=1.92x-38.0 (F_1,69=17.5, P=0.001) at peak lactation, and (B) relationship prior to breeding not significant (P=0.156) and y=2.00 x-44.7 (F_1,35=22.16, P=0.001) at peak lactation.