Breznock A W, Harrold J B, Kawakami T G
Lab Anim Sci. 1977 Apr;27(2):222-8.
A cage was developed which included a squeeze wall for easy handling of the gibbon (Hylobates lar) and which provided gibbon breeding pairs with privacy from others of the same species. Females living in this environment displayed menstrual and vaginal eversion cycles averaging 30 days (range 22-44). Twelve compatible pairs produced eight live infants from 15 conceptions in a 33-month period. Two full term stillbirths, two abortions, and three current pregnancies accounted for the other seven conceptions. Monthly uterine palpations were performed and pregnancy could be detected as early as 27 days after conception. The compatibility of the mating pairs was determined to be the major factor in the natural breeding of gibbons in captivity. This was demonstrated by obtaining only 12 compatible pairs from 22 attempted pairings.
