Endocrine correlates of behavioural oestrus in the female giant panda ( Ailuropoda melanoleuca ) and associated hormonal changes in the male

Urinary excretion of oestrogens and androgens by a pair of giant pandas was monitored by radioimmunoassay during behavioural oestrus through two successive breeding seasons. The excretion of oestrogens by the female was at a maximum during the proceptive period and lower during the period of receptivity. In the first breeding season studied, elevated androgen excretion in the male coincided with peak receptivity in the female. The study indicates that accurate timing of natural mating or artificial insemination could be achieved by monitoring oestrogen excretion in the female.