In order to control population growth rates, a decision was made to sterilize most of the free-ranging, wild rhesus macaque females of Silver Springs, Florida. Between October 1987 and March 1988, the five females who had been sterilized and released in the fall of 1986 were matched with five intact females in a behavioral study. While there were differences between the behaviors of the sterilized and intact females, the differences can be attributed more to differences in age, rank, and other factors than to the sterilization. Clinical data collected and reported on the monkeys is unremarkable.