A survey of bonobo (Pan paniscus) oral contraceptive pill use in North American zoos

Contraception is an essential tool in reproductive management of captive species. The Association of Zoos and Aquariums (AZA) Reproductive Management Center (RMC) gathers data on contraception use and provides recommendations. Although apes have been given oral contraceptive pills (OCPs) for at least 30 years, there have been no published reports with basic information on why the pill is administered, formulations and brands used, and effects on physiology and behavior. Here, we report survey results characterizing OCP use in bonobos (Pan paniscus) housed in North American zoos, as well as information accumulated in the RMC's Contraception Database. Of 26 females treated, there have been no failures and nine reversals. The most commonly administered OCP formulation in bonobos contained ethinyl estradiol (EE) 35 μg/norethindrone 1 mg. Few females on combined oral contraceptives (COCs) were given a continuous active pill regimen; a hormone‐free interval of at least 5 days was allowed in most. Crushing the pill and mixing with juice or food was common. Females on COCs seldom experienced breakthrough estrus or bleeding, while these conditions were sometimes observed for females on continuous COCs. All females on COCs exhibited some degree of perineal swelling, with a mean score of 3 or 3+ most commonly reported. Behavioral changes included less sexual behavior, dominant females becoming subordinate, and a negative effect on mood. No appreciable change in weight was noted. Taken together, these results indicate that OCPs are an effective and reversible contraceptive option for bonobos that can be used by zoos and sanctuaries to limit reproduction. Zoo Biol. 35:444–453, 2016. © Wiley Periodicals, Inc.