title: Length of gestation in mice under a 21-hour day.
mesh_terms: D000818:Animals; D002940:Circadian Rhythm; D003624:Darkness; D005260:Female; D008027:Light; D008098:Litter Size; D051379:Mice; D008810:Mice, Inbred C57BL / Q000502:physiology*; D010507:Periodicity; D011247:Pregnancy; D011270:Pregnancy, Animal; D013997:Time Factors