MEDORA (AP) -- Theodore Roosevelt National Park officials plan to use birth control in wild horses for the first time.
The park's horses will be rounded up next month and about 90 of them sold at a public auction Oct. 23. Auctions have been used in the past to control the herd size. This time, about 25 mares will be given a contraceptive to prevent pregnancy.
The contraceptive administered with a dart gun lasts about four years. The experiment will compare vaccinated horses to a control group of 25 non-vaccinated mares to see how well the birth control works.
Park wildlife biologist Mike Oehler (AY'-ler) says the experiment is aimed at eliminating the roundups, which are expensive and can be traumatic for the animals. Two years ago, a helicopter used to herd horses into corrals crashed. The pilot and Oehler suffered minor injuries.
The park has about 165 wild horses. Officials say the ideal population is between 60 and 90.
