Reproductive Activity of the Japanese Long-tailed Field Mouse Apodemus argenteus under Laboratory Conditions

Abstract

The reproductive activity of captive Apodemus argenteus was observed in detail from 1986 to 1989, and 149 births were recorded. Parturition occurred throughout the year, but peaked from March to July. Reproductive activity of the live-trapped generation did not differ from that of the second, third or fourth generations. Litter size was 4.21 on average, and the earliest age at first parturition was three months. The time interval between successive births was 33.6 days on average, the shortest being 20 days. Sexual behavior was also observed, and a necessity for experience was indicated.