Breeding orangutans at Perth Zoo: Twenty years of appropriate husbandry
Publication Type: |
Journal Article |
Year of Publication: |
1990 |
Authors: |
Rosemary J. Markham |
Publication/Journal: |
Zoo Biology |
Publisher: |
A Wiley Company, Inc., Wiley Subscription Services |
Keywords: |
diet, husbandry, mortality, reproduction, social-structure |
ISBN: |
1098-2361 |
Abstract:
Abstract 10.1002/zoo.1430090212.abs The Perth Zoo orang-utan husbandry strategy, which has been the foundation of 20 years of success in breeding, health, and longevity, is based on respect for the solitary arboreal nature of the species. The orang-utans are housed singly at night and fed only in their night dens. Diets are based on the weight and energy expenditure of the individuals. During the day they are housed singly or in very small groups that correspond in size and structure to wild population units. Adult males and females are only introduced for breeding purposes. Large climbing frames, which permit visual and vocal contact, dominate the day enclosures. A wide variety of manipulable objects are provided daily to enhance activity levels. Since 1968 there have been 21 births, 14 surviving infants, and no post-infancy deaths. All the mature animals are fertile. The major health problems of captive orang-utans and the most common causes of adult mortality have been absent from the colony. The husbandry method used has made it possible to record detailed reproductive data including complete menstrual cycle records for 8 females since 1981, the observation and quantification of cyclic proceptivity for all mature females, the calculation of 19 gestation periods, and the measurement of post-partum amenorrhea and interbirth intervals. Urinary hormone analysis is used regularly to confirm ovulation. A long-term study of the hormones mediating the development of secondary sexual characteristics in males was started in 1988. Captive orang-utans do not have a fertility problem, but the captive population is threatened by the unacceptably high mortality rate in young adults. This appears to be related to inappropriate husbandry methods. The most neglected aspect of orang-utan husbandry is natural social group size and structure.