Testis development in the vole, Microtus agrestis, subjected to long or short photoperiods from birth.

Voles exposed to long photoperiods (16L:8D) from birth became sexually mature at 40-45 days and remained so up to the end of the experiment at 6 months of age. In short photoperiods development was inhibited up to 60 days but the majority of males became sexually mature between 4 and 6 months of age.