Behavioral and physiological evidence of sexual climax in the female stump-tailed macaque (Macaca arctoides).

Intense tonic/clonic uterine contractions and sudden increases in heart rate coincided with the behavioral homolog of a male ejaculatory response (minus seminal emission) in a normal female stump-tailed macaque engaged in homosexual mounting episodes. The behavioral patterns were also observed in four of ten females during 5 to 40 percent of heterosexual copulations. These observations demonstrate the existence of an orgasmic response in a nonhuman primate.