Most snakes, including copperheads, cat snakes, cobras, corn snakes, kingsnakes, green snakes, smooth snakes, and pythons, are oviparous snakes, meaning they lay eggs. Other snakes, such as vipers, sea snakes, garter snakes, boa constrictors, and anacondas, are viviparous snakes who give live birth. Viviparous snakes nourish their developing babies through a placenta or yolk sac.
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Sea snakes: snakes that give live birth
Sea snakes rarely if ever visit land. Snake eggs generally do not develop underwater, so most sea snakes give live birth. Kraits are the exception; this species of sea snake visits land to mate and lay eggs. Sea snakes usually give birth to three or four babies at a time.
Vipers and pit vipers
Most vipers and pit vipers give live birth. There are a few exceptions, though. For instance, bushmasters and Malayan ground pit vipers lay eggs. Vipers and pit vipers are venomous snakes that can be found in Europe, Asia, Africa, and North, Central, and South America.
The ovoviviparous garter snake
Garter snakes are unique in that they are ovoviviparous, meaning that their babies develop inside eggs in the mother's body. Once the babies hatch, the mother gives live birth to her babies.
Garter snakes typically mate in spring shortly after hibernation. Many male garters will try to mate with one female. Female garter snakes can actually store sperm for years, and she can fertilize her own eggs even if she doesn't find a suitable mate.
Female garter snakes are typically pregnant for two to three months. They can give birth to litters ranging from three to 85 babies. Most of the time, a mother will give birth to approximately 12 babies at a time.
Anacondas breed for weeks
All anacondas, including Bolivian, green, yellow, and darkly spotted anacondas give live birth. Anacondas live in or near water where snake eggs cannot incubate and develop.
Courting takes place for weeks during the spring. Female anacondas are thought to leave a scent trail to attract male partners. Sometimes, two to 12 males will form a kind of breeding ball, coiling around one female. The males can stay coiled around the female for up to four weeks. Breeding typically occurs in water.
The anaconda babies receive nourishment through a yolk sac while they develop inside the mother. Each baby snake is surrounded by a clear membrane as well. The baby anaconda must break out of the membrane once he is born and begin to fend for himself right away.
Rattlesnakes are ovoviviparous
Like garter snakes, rattlesnakes are ovoviviparous. A rattlesnake's babies incubate in egg sacs in the mother until she gives live birth. Each baby is born with a cellophane-like wrapper surrounding him. The baby must break through the wrapper before he can take his first breath.
One to two weeks after the baby is born, he sheds his skin for the first time. Once he has shed his skin, the young rattlesnake will venture out on his own to find food. It is not uncommon for the young snake to follow the scent of his mother to a den where he can hibernate with her during the winter months.
Boa constrictors may not breed annually
Interestingly, while male boa constrictors breed annually, females may not. A female releases a scent from her cloaca to indicate to males when she's ready to mate. Depending on the temperature in a boa constrictor's environment, a female carries her babies from five to eight months. A female boa constrictor can give birth to 10 to 64 babies at a time, but the average litter size is 25.
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