Rearing of Orphan Elephant Calves in Sri Lanka for Release into the Wild: Survival and Cause-Specific Mortality
In Sri Lanka and other Asian countries there is an increasing incidence of conflict between free-ranging elephants (Elephas maximus maximus) and human populations. One consequence of this conflict is that many young elephant calves become orphaned, either because their mother is killed or the calf loses contact with its mother and the herd. Elephant calves may also be abandoned by their mothers if they are congenitally weak or malformed. Orphaned calves become distressed and will die within a short time unless they are provided with medical care, suitable food and protection. Veterinary professionals and government agencies in many Asian countries act to save and provide short-term care for orphan calves. Ideally, after a period of recovery orphan calves would be returned to their mother and/or into a wild environment, but in practice this is usually impossible and calves become dependent on human care.
The Elephant Transit Home (ETH) in Sri Lanka was established in 1995 with the objective of rehabilitating orphan wild elephant calves back into the wild. Up to 2017 the ETH has released 118 calves back to the wild and 17 of them have given birth since release. A total of 319 calves have been accepted by the ETH, 225 of them were estimated to be less than one year of age, with some as young as one day old. Calves are released at 5–6 years of age. This paper describes the management regime for calves, the diseases they suffer from and their mortality during their stay at the ETH.
One hundred forty-two calves have died during their stay at the ETH, 115 (81% of mortalities) within a month of arrival and 20 (15%) within one to six months after arrival. These mortalities were caused by weakness, stress, starvation, injuries and infectious diseases. From 6 months after arrival until release into the wild only 7 (5%) calves died. After the initial period of recovery the calves at the ETH have a similar, or lower mortality than calves in zoos and other captive elephant facilities.
The experience of the ETH shows that orphan elephant calves can be successfully reared in a semi-natural environment that allows their eventual release into the wild. These findings are relevant both to the welfare of orphan calves and to the conservation of wild elephant populations.