<P> Females secrete small amounts of sex pheromones, which leave a trail the males follow using their tongues and Jacobson's organs as guides . Once a receptive female has been located, the male often spends several days following her around (a behavior not common outside of the mating season), frequently touching and rubbing her in an attempt to stimulate her . </P> <P> The males of some species, such as timber rattlesnakes (C. horridus), fight each other during the mating season, in competition over females . These fights known as "combat dances" consist of the two males intertwining the anterior portion of their bodies, often with their heads and necks held vertically . The larger males usually end up driving the smaller males away . </P> <P> Although many kinds of snakes and other reptiles are oviparous (lay eggs), rattlesnakes are ovoviviparous (give birth to live young after carrying eggs inside). The female produces the ova ("eggs") in her ovaries, after which they pass through the body cavity and into one of her two oviducts . The ova are arranged in a continuous chain in a coiled section of the oviduct, known as the "tuba". Male rattlesnakes have sexual organs known as hemipenes, located in the base of the tail . The hemipenis is retracted inside of the body when mating is not occurring . Females can store semen for months in internal recesses known as spermathecae, which permits them to mate during the fall, but not fertilize the ova until the following spring . The Arizona black rattlesnake (C. oreganus cerberus), has been observed to exhibit complex social behavior reminiscent of that in mammals . Females often remain with their young in nests for several weeks, and mothers have been observed cooperatively parenting their broods . </P> <P> Rattlesnakes generally take several years to mature, and females usually reproduce only once every three years . </P>

Do rattlesnakes lay eggs or give birth to live young