This file contains the fall elk body fat (IFBF) and pregnancy data used in analyses. For fall measurements, lactation status is included; in late-winter/spring measurements lactation status could not be determined. Age was estimated from tooth eruption and wear patterns. Pregnancy was estimated from PSPB levels in the blood. IFBF was estimated following the revised methods of Cook et al. (2010) that included an allometrically scaled MAXFAT index.