Comparative studies on the timing of reproduction and foetal number in six species of Australian conilurine rodents (Muridae: Hydromyinae)

The timing of reproduction and number of foetuses in the wild caught conilurine rodents Notomys mitchelli, N. alexis, Pseudomys albocinereus, P. hermannsburgensis, P. delicatulus and P. nanus was ascertained from museum preserved specimens. The two species from southern Australia ( N. mitchelli, P. albocinereus ) appeared to have a breeding season from late winter to early summer, whereas in those from the central region ( N. alexis and P. hermannsburgensis ) no such breeding season was evident. The little data available for the northern species, P. delicatulus , suggests at least reproduction during the winter. Foetal number was similar for the four species from southern and central Australia but tended to be slightly less in the two northern species. The significance of these findings in relation to the control of reproduction is briefly discussed.