Prey such as frogs, fish and other snakes are held in the jaws after captured for a few moments to allow them to succumb to the venom. If the victim flees before the venom takes effect, the cottonmouth tracks it by scent. It then examine the carcass by touching it with its tongue to make sure that the prey is dead. Then it swallows the prey headfirst. Unlike non-venomous reptiles, the cottonmouth takes its time when feeding, perhaps because its prey is dead.
Newborn cottonmouths have a unique predatory technique.
Breeding takes place during the spring. It begins with the male nudging the female's back and sides. This continues for as long as several hours, until she exposes her tail and opens her cloaca for copulation. Ovulation takes place only in alternate years. The gestation period usually lasts from 3-4 months.