Before breeding your spiny mice, learn what to expect. Mice are prolific animals and breeding should only be done if you know you will find homes for all your new little companions. Here are some of the basics:
Nests are shared and several individuals literally pile on top of each other. “Nest” is probably the wrong word to use as spiny mice do not usually build a nest, but simply use a hollow in the litter or shelter under rocks or in crevices.
The gestation period for these mice is 35 to 45 days, with an average litter size of just two. The young are born well developed with their ears open and their fur already grown in. The eyes may be open at birth or will open in the first few days. Within a couple of days they will begin exploring the cage. The female does not retire from her fellows when about to give birth but gives birth in a standing position. Once the babies are born, any female will feed any baby and it is not unusual to see a lactating female with a newborn feeding from one nipple and have an almost weaned animal on another.
Within a couple days the babies will be exploring the cage. Babies are weaned at 14 to 21 days. They become sexually mature at about seven weeks of age but their growth is not complete until they are about six months old. Even after that their weight continues to rise.