Abstract

Reproductive events related to time of breeding and fecundity among species of New Guinean Rattus are examined relative to latitude, altitude, and possible climatological cues. At least half of the 25 subspecies examined can breed in any month, and this capability appears to be unrelated to annual photoperiod fluctuations and ambient temperature at different altitudes. Both rainfall and commensalism may exert strong influence on local breeding regimes. This, the first reproductive analysis of all New Guinean species of this genus, permits comparison with similar events in Australian Rattus, and generalised patterns of breeding in these Australasian species are proposed.