In this study, four crab-eating fox females (Cerdocyon thous) maintained at the Federal University of Mato Grosso Zoo, Cuiabá, Brazil, were investigated for 12 months, using feces measurement of estradiol and progesterone concentrations. Fecal collections were performed three times a week for hormone extraction. Two methods of analysis, Elisa (EIA) and Radioimmunoassay (RIA), were used in the measurement of progesterone (P4) and estradiol (E2) metabolites. The aim of this study was to compare and validate two different methods of hormone measurement for C. thous. There were no differences regarding the method used. The Radioimmunoassay technique proved to be more sensitive, however, both showed similar results.Keywords: radioimmunoassay; Elisa; estradiol; progesterone; fecal
