The Reproductive Physiology of the Plains Viscacha, Lagostomus Maximus

Summary. Plains viscacha were established in the laboratory to investigate their reproductive physiology. The species was found to have a mean oestrous cycle length of 45·0±1·2 days and a mean gestation period of 153·7±0·5 days. There was rarely an immediate post partum oestrus but if the young died at birth, oestrus occurred 17·1±3·6 days later. When the young suckled, the mother exhibited a lactation anoestrus of 55·9±3·7 days. The litter size was nearly always two, and these well-developed young were frequently of opposite sex. In captivity, births occurred throughout the year.