While some snakes lay eggs in a nest, others keep them inside their bodies until they hatch. Either way, female snakes don't necessarily need a mate to produce eggs. Some of those eggs may be infertile, though, meaning that they don't contain viable embryos. Surprisingly, a single snake who's never been bred with a male can give birth to viable young which she can fertilize all by herself.
A Traditional Two-Snake Household
Female snakes usually reproduce by breeding with one or more males, who fertilize their eggs. A female will then typically lay her eggs within weeks or months of copulating. This doesn't mean that either mom or dad will stick around to help hatch and rear the young. Only the female may either brood her eggs, staying with them to keep them warm after she lays them if she's oviparous, or the eggs will stay within her body if she's ovoviviparous. Some oviparous snake moms simply abandon their eggs, usually after burying them in a hole. Once the eggs hatch, some mother snakes remain with the babies for a short period of time to protect them.
Sisters are Doin' it for Themselves
While traditionally a female snake needs to mate with a male snake to produce fertilized eggs, some -- like the flower pot snake -- produce young by a process called parthenogenesis, also known as asexual reproduction. Flower pot snakes asexually produce identical female offspring who are healthy, according to the Florida Museum of Natural History. In addition, a study published in the September 2012 edition of "Biology Letters" found that cottonmouth and copperhead snakes, pit vipers who normally mate to produce young, were also able to reproduce asexually. Their young all turned out to be male and weren't clones of their mothers, but rather had only half of her DNA and were usually stillborn or deformed. Note that pit vipers are ovoviviparous and carry their eggs within their bodies.
Your Snake had a Suitor ... Years Ago
Some snakes lay a clutch of eggs years after being adopted. While the eggs that your snake lays may appear to be produced asexually, the truth may be that she was bred before she came to live with you. Once a snake breeds, she is able to store her suitor's sperm in her body for up to six years in her cloaca, according to ExoticPetVet.com. This sperm remains viable and can fertilize her eggs even years after mating, states "Venomous Snakes." So while Sissy may not have a mate around, she certainly can lay eggs that her body fertilizes with the sperm from an encounter she had with a previous suitor.
There are Eggs but No Babies or Babies but No Eggs
In rare cases, a snake may lay a clutch of eggs without mating, which are infertile if she isn't able to fertilize them herself. These eggs are called slugs and won't hatch. Even after mating with a male, a female snake's clutch of eggs may contain a few of these "bad" eggs among the viable ones. Some snakes even give birth to live young without any eggs, much like mammals. These snakes are called viviparous and tend to mate with males to reproduce just as most oviparous or ovoviviparous ones do.
- ExoticPetVet.net: Reptiles: Reproduction "From Egg to Adult"
- Florida Museum of Natural History: Brahminy Blind Snake, Flower Pot Snake [NON-NATIVE]
- Newton -- Ask a Scientist: Viviparous Snakes
- ArizonaReptile.com: Feeding a Corn Snake
- Virginia Cooperative Extension: Managing Wildlife Damage: Snakes
- Kidzone: Hey Baby!
- Animal Questions: Do Snakes Lay Eggs?
- Biology Letters: Facultative Parthenogenesis Discovered in Wild Vertebrates
- Venomous Snakes; Cynthia Berger
- Fairfax County Public Schools: Eastern Garter Snake
- Southern Mexico: The Cancún Region, Yucatán Peninsula, Oaxaca, Chiapas, and Tabasco; Les Beletsky
- Smithsonian National Zoological Park: Black Rat Snake
- VMSherp.com: How To Breed Cornsnakes
- BBC: Snake Gives 'Virgin Birth' to Extraordinary Babies
- My Pet Python: Can a Ball Python Lay Eggs Without Mating?
- Jupiterimages/Photos.com/Getty Images