Reproduction of raccoons (Procyon lotor) in North Dakota

Necropsies and observations of captive and radio-equipped individuals provided reproductive data from a raccoon population in the northern prairies. The mean parturition date of adult females was 8 May and the mean litter size was 4.8. Only two of the 14 yearling females examined prior to 1 July were pregnant; they had estimated parturition dates of 20 May and 22 June. Penes of most yearling males became extrusible in July or August. Testes weights and sperm smears suggest that yearling males in North Dakota are not reproductively active. Reproductive patterns of raccoons near the northern periphery of their range and those at lower latitudes are compared and discussed.