The reproductive biology of Bennett's wallaby (Macropus rufogriseus rufogriseus) ranging free at Whipsnade Park

Between August 1981 and October 1982, 76 female and 50 male of the estimated 400 Bennett's wallabies at Whipsnade were caught and examined. Sixty-four of the adult females inspected (84%) were carrying pouch young. A small captive breeding colony was established in the laboratory. Weight and growth curves were established for captive born pouch young and these curves were used to determine the approximate age of pouch young examined at Whipsnade. Eighty-four percent of births occurred in August and September, exactly a six month difference from births reported for this species in Tasmania. The mean length of pouch life of wild living wallabies was 247 days with a range of185–284 days. Young wallabies were observed accompanying their mothers for up to 204 days after emerging permanently from the pouch. Sixty-three percent of young vacated the pouch in May. Sixty-three percent of the total (104) pouch young examined in the course of this study, from animals caught or from post mortem records, were male, but teat selection showed a random distribution. The gestation period from removal of pouch young to day of birth was 27·3 days. The Bennett's wallaby showed precise seasonal breeding with embryonic diapause that may extend for up to 11 months.