During the course of a programme to breed the Asiatic elephant, Elephas maximus, in captivity, the oestrous cycles of eleven adult females were studied. Two methods were used for detecting oestrus : (1) daily testing with a male elephant, and (2) urogenital smear cytology.
Overt signs of oestrus were not observed but 'standing' oestrus was detected in ten animals. The duration of oestrus ranged from 2 to 8 days with a mode of 4 days. Oestrous cycles in six animals ranged from 18 to 27 days with a mean of 22 days. Urogenital smear cytology failed to indicate accurately the onset of behavioural oestrus but increases in the number of cornified cells may occur before, during and slightly after behavioural oestrus. Considerable mating activity occurred during oestrus. A description of mating behaviour is presented.
The findings are discussed in relation to breeding elephants in captivity and to the phenomenon of temporal gland activity.