Copulatory behavior and fertility of male house musk shrews (Suncus murinus) paired with one, two and four females each.

In order to improve the productivity of house musk shrews, we investigated whether a male could impregnate more than one female within 24 h. Eighteen males and 40 females aged one year were used in this experiment. The mating systems were as follows: one male was paired with one female, one male was paired with two females, and one male was paired with four females. In the fertility rate, six out of 6, 4 of 12 and 4 of 20 females became pregnant and gave birth under three systems, respectively. In the copulatory behavior, numbers of intromissions and ejaculations were more in the 1:1 mating group as compared with the 1:2 and 1:4 groups. We conclude that it is possible for a male to impregnate about one female within 24 h.