when do mice reproduce
On the third day, the ears unfold with the ear canal opening on the tenth day. Eyes open on the fifteenth day, and the young are weaned between day 25 and 35. Deer mice can reproduce when they are 35 days old, but they usually breed for the first time at 49 days. 1  Key Reproductive Features. 2  iteroparous. 3  year-round breeding. 4  gonochoric/gonochoristic/dioecious (sexes separate) 5  sexual. 6  fertilization. 7  viviparous. 8  post-partum estrous.