page_title: Rattlesnake
section_title: Reproduction
hierarchical_section_title: Rattlesnake / Reproduction
caption_attribution_description: English: Rattlesnake Dance, Portola Valley, Windy Hill Open Space Preserve, San Mateo County, California. – "It seemed like part dance, part wrestling match. I thought they might be courting, but it's a combat ritual between two male Northern Pacific Rattlenakes (Crotalus oreganus oreganus)."
context_page_description: Rattlesnakes are a group of venomous snakes of the genera Crotalus and Sistrurus of the subfamily Crotalinae. The scientific name Crotalus is derived from the Greek κρόταλον, meaning "castanet". The name Sistrurus is the Latinized form of the Greek word for "tail rattler" and shares its root with the ancient Egyptian musical instrument the sistrum, a type of rattle. The 36 known species of rattlesnakes have between 65 and 70 subspecies, all native to the Americas, ranging from southern Alberta, Saskatchewan, and southern British Columbia in Canada to central Argentina.
  Rattlesnakes are predators that live in a wide array of habitats, hunting small animals such as birds and rodents.
  Rattlesnakes receive their name from the rattle located at the end of their tails, which makes a loud rattling noise when vibrated that deters predators or serves as a warning to passers-by. However, rattlesnakes fall prey to hawks, weasels, king snakes, and a variety of other species. Rattlesnakes are heavily preyed upon as neonates, while they are still weak and immature. Large numbers of rattlesnakes are killed by humans.
context_section_description: Most rattlesnake species mate during the summer or fall, while some species mate only in the spring, or during both the spring and fall.
  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.
  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.
  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. The hemipenis is similar to the human penis. 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.
  Rattlesnakes generally take several years to mature, and females usually reproduce only once every three years.
caption: Two male Northern Pacific rattlesnakes (C. oreganus oreganus) engage in a "combat dance"
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