Reproduction

     Fertilization is internal in snakes; as in lizards, the males have paired copulatory organs, either of which may be used in mating. Females of some species can store sperm for several years to insure future fertilization. In most species the female lays eggs; in some the eggs are incubated and hatched within the mother's body; in a few there is true viviparity, or live birth, with the young nourished by means of a placenta rather than an egg. Some egg-laying snakes brood the eggs, but there is no parental care of the young.