Reproduction in the pseudomyine rodent Mesembriomys gouldii (Gray) (Muridae)

Abstract

M. gouldii is polyoestrous and polyovular. In the non-pregnant female the oestrous cycle is 26 � 3.5 days (range 21-35 days). Mucus appears irregularly during the dioestrous interval and seems to be derived from epithelial cells of the vagina. Ovulation is spontaneous and usually alternate, one to four corpora lutea being formed. The corpora lutea of the unmated female are functional until the 15th-17th day of the cycle. Gestation lasted from 43 to 44 days, a "placental sign" occurring between the 22nd and 33rd day. A post-partum oestrus and mating occur but no delay in implantation was recorded. Litter size ranges from one to three. The young are well developed at birth, and cling tenaciously to the teats for the first few weeks. Growth is rapid and the young can be weaned after 42 days. This pattern of reproduction is compared with the limited data from other Australian Muridae.