Influence of daylength experienced by dams on post-natal development of young meadow voles (Microtus pennsylvanicus).

Meadow voles born to dams kept in short days (SD) beginning 5 or 11 weeks before parturition (SD-5, SD-11) had less developed testes, gained weight more slowly and built larger nests than did young gestated and maintained in long days (LD). Pelage development was greater in SD than in LD young at 21 and 45 days of age. At weaning, SD-5 young had less dense fur and shorter guard hairs than did SD-11 young, indicating that the photoperiodic history of dams before insemination affects the post-natal pelage development of their progeny. Short daylengths experienced by dams before mating may facilitate winter preparedness of their offspring.