Reproductive Ecology of the Female African Elephant

During 1957 through 1964, 146 female African elephants (Loxodonta africana) were collected in Uganda; data were also obtained from 23 pregnant elephants collected in Zambia in 1967. The reproductive status of 142 adult and subadult female elephants in Uganda was 17.6 percent pregnant, 79.6 percent not pregnant, 2.1 percent estrus, and 0.7 percent status unknown; 45.1 percent lactating and 5.6 percent lactation status unknown. Female elephants reach sexual maturity between 7 and 15 years in age. The reproductive rate of elephants in Uganda is decreasing. The duration of lactation was about 4.8 years. The postpartum conception interval has increased from 24.1 months in 1947-1950 (Perry 1953) to 77.0 months in 1964. Elephants in Uganda may breed during all months of the year; however, breeding peaks do occur because there are significantly more young born in the rainy seasons than the dry seasons. About 2 months after the onset of the rains, the physiological state of the female is apparently enhanced, and increased reproductive activity ensues. The increased activity continues about 2 months beyond cessation of the rains. In Zambia, breeding increases as the rainy season progresses and as the dry season progresses, breeding decreases. J. WILDL. MANAGE. 37(4):524-534 The range of the African elephant continues to dwindle with man's inexorable increase in population. Man's activities have destroyed habitat, disrupted migratory pathways, changed distributions, and altered behavior patterns with the net effect that much of the remaining habitat is inhabited by more elephants than it can support (Brooks and Buss 1962, Simon 1962, Buechner et al. 1963, Sikes 1968, and others). Parts of Kenya, Uganda, and Tanzania have excessive numbers of elephants long overdue for reduction to a level commensurate with the carrying capacity of their habitat. Such reduction programs should be based on sound ecological knowledge gained from research. Knowledge of reproduction in the elephant is especially critical to understanding many aspects of their ecology, yet this is a facet of our understanding that is incomplete. Anatomy and development of the female reproductive system have been reported by Perry (1953, 1964) and Amoroso and Perry (1964). Early reports on age at sexual maturity and duration of gestation of the Indian elephant (Elaphas maximus) were made by Seth-Smith (1932), Hundley (1934), Burne (1943), and Flower (1943). Hill (1953) included information of a general nature on reproduction of elephants. Early studies of the corpus luteum of the African elephant show either small quantities of progesterone or none (Edgar 1952, Short and Buss 1965, Short 1966, Smith et al. 1969). Perry (1953) postulates that successive generations of corpora lutea may appear during the middle of gestation, whereas Buss and Smith (1966) give evidence which tends to refute this idea. Age at which females reach puberty has been reported by Perry (1953), Buss and Smith (1966), Laws (1966, 1967, 1969). Estimating age of wild elephants was initiated by Johnson and Buss (1965), Laws (1966), Sikes (1966), Krumrey and Buss (1968). The objective of this report is to describe some of the ecological characteristics of reproduction in the female elephant. The National Science Foundation (to I.O.B.) and the Rockefeller Foundation (to N.S.S.) supported the field work conducted in East Africa. The New York Zoological Society and Medical and Biological Research, Washington State University provided additional support. We are grateful for the cooperation given to our field work 524 J. Wildl. Manage. 37 (4):1973 This content downloaded from 157.55.39.137 on Fri, 27 May 2016 05:42:31 UTC All use subject to http://about.jstor.org/terms AFRICAN ELEPHANT REPRODUCTION Smith and Buss 525 by L. Tennant, Senior Warden of the Uganda Game Department. Members of the Uganda Forest Department directed by G. Webster were helpful at all times in supporting our field work. W. O. Pridham and J. J. Heppes, formerly District Supervisors of the Uganda Game Department, deserve special acknowledgment for their assistance with the collecting of elephants. Senior Game Guard C. Rwakaikara deserves much credit for his incredible skill in tracking elephants. W. R. Bainbridge, Chief Game Officer of Zambia Game and Fisheries and J. Hanks were instrumental in furnishing valuable specimens from the Luangwa Valley, Zambia.