Remote Monitoring of Ovulation and Pregnancy of Yellowstone Bison

The physiological mechanisms that control reproductive success of wild bison (Bison bison) are not known, and the relatively small scattered herds prevent intensive study. Environmental, demographic, and physiological factors all play major interrelated roles in reproductive self-regulation. Thus, we validated the use of urinary and fecal steroid analysis as a means of detecting ovulation and pregnancy in uncaptured free-roaming ungulates, and identified the physiologic mechanisms that govern reproductive success in wild bison. Free-roaming bison of 2 subpopulations of the Yellowstone National Park herd were observed during 1989-91