Excretory Fate of Estradiol and Progesterone in the African Elephant (Loxodonta africana) and Patterns of Fecal Steroid Concentrations throughout the Estrous Cycle S. K. Wasser,* , † ,1 S. Papageorge,‡ C. Foley,§ and J. L. Brown¶ *Center for Wildlife Conservation, 5500 Phinney Ave N., Seattle, Washington, 98103-5897; †Division of Reproductive Endocrinology, Department of Obstetrics and Gynecology, University of Washington School of Medicine, Seattle, Washington 98195; ‡School of Veterinary Medicine, Tufts University, North Grafton, Massachusetts 01536; §Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey 08544; and ¶Conservation and Research Center, 1500 Remount Road, Front Royal, Virginia 22630 Accepted January 18, 1996 We developed and validated a noninvasive method to quantify fecal estrogens and progestins as a tool for monitoring long-term ovarian activity in free-ranging Af- rican elephants. The lag times between iv injection of [ 3 H]estradiol and [ 14 C]progesterone and peak excretion of radioactivity in urine and feces were approximately 4 hr and 48 hr, respectively. The majority of progesterone metabolites recovered was excreted in feces (55%) ver- sus urine (45%), whereas comparatively little of the re- covered estradiol metabolites were excreted in feces (5%) compared to urine (95%). Intrasample variation in fecal hormone concentrations was extremely high but could be substantially reduced by extracting well-mixed fecal powder from freeze-dried samples, taken from the central or premixed portion of the wet sample. This method resulted in a close correspondence between matched serum and fecal progestins (mean correlation = 0.81, range 0.61–0.94) collected from five nonpregnant adult females over a 7-month period. Fecal estrogen pro- files were more ambiguous, tending to overlap with those of fecal progestins. We conclude that analyses of fecal progestins can provide an effective, noninvasive means of characterizing ovarian activity in free-ranging African elephants. © 1996 Academic Press, Inc. African elephants (Loxodonta africana) were heavily poached during the late 1970s and early 1980s, dra- matically reducing numbers from 1.5 million to ap- proximately 600,000 individuals between 1980 and 1986 (Ricutti, 1993). In response, the Convention on International Trade in Endangered Species listed the African elephant as an Appendix 1 species in 1989— the highest protection status given to an endangered species. This action virtually eliminated the ivory mar- ket, creating one of the most successful international bans on poaching in history. However, pressure still persists to downlist the African elephant and thus lift the ivory ban. Evidence from Tanzania suggests that the long-term consequences of poaching reach far beyond that of slaughtering elephants (Poole, 1989; Balozi, 1989; 1 To whom correspondence should be addressed. General and Comparative Endocrinology 102, 255–262 (1996) Article No. 0067 0016-6480/96 $18.00 Copyright © 1996 by Academic Press, Inc. All rights of reproduction in any form reserved. 255