Charles L. Douglas, Comparative Ecology of Pinyon Mice and Deer Mice in Mesa Verde National Park…
“ Subadult pelage having mostly replaced juvenal pelage; mice often as large as adults; testes of males often abdominal in breeding season; gray juvenal pelage may persist on head of some individuals. [476] Adult: Adult pelage present; body usually largest of all animals in population; females may have enlarged mammae from nursing previous litters; testes of males usually scrotal in breeding season; gray pelage may be present on head of some individuals.Old individuals in the field could not be distinguished from adults ”
