The Capacitation Time and Fertilizing Life of Snowshoe Hare Spermatozoa in the Female Tract of the Rabbit

Hybrid fertilization can occur between several mammalian species (Chang & Hancock, 1967), but there is no conclusive proof that spermatozoa need to be capacitated before they can effect such fertilization. The time required for hybrid capacitation and the ability of spermatozoa to retain their fertilizing capacity in the female tract of another species has not been studied. Nevertheless, it has been shown that rabbit spermatozoa can slowly complete part, if not all, of their capacitation for normal fertilization in the uterus of the rat and bitch (Bedford & Shalkovsky, 1967; Hamner, Jones & Sojka, 1968). This paper reports (1) the capacitation time for hybrid fertilization of snowshoe hare spermatozoa in the rabbit Fallopian tube, and (2) their fertilizing life in the female tract of the domesticated rabbit. Sexually mature snowshoe hares, Lepus americanus, were killed or