Abstract

The Tasmanian devil, S. harrisii, is polyovular and monoestrus and embryonic diapause was not found. The mean number of pouch young for 69 litters was found to be 2.95. The number of young in a litter varies with the age of the mother. More young are born than can be accommodated in the pouch. The time of breeding varies from year to year, mating taking place in March. The percentage of breeding females varies annually as well as from place to place, being found to be as low as 31 % in one area. The devil has a high reproductive potential because there are no losses at the pouch-young stage. This is offset by poor recruitment of juveniles into the population.

Pseudopregnancy was found to occur.

The sex ratio of both pouch young and adults favoured the female. The development and growth of the young is described.