Snakes are such a large and successful family of animals that they reproduce in more than one way. They lay eggs, give birth, or do both.
In the last way, the female lays very, very thinly shelled eggs in her oviduct, where the babies hatch. She then gives birth to the babies.
About seventy percent of the 3,000+ snake species in the world lay eggs.
Do Snakes Give Birth to Live Young or Lay Eggs?
Snakes lay eggs, birth their young, or do both. Most snakes lay their eggs or are oviparous. Those that give birth to live babies are viviparous. Ovoviviparous snakes deposit eggs inside of their bodies, which then hatch. The baby snakes are then birthed by their mothers.
Oviparous Snakes
The vast majority of snake species in the world make babies by laying eggs.
Females lay any number of eggs in a clutch, from one to 100, depending on the species and the health of the individual snake.
Burmese pythons even lay up to 100 eggs. Eggs are oblong and leathery, instead of being hard like bird eggs.
Baby snakes have an egg tooth, which helps them rip through the shells. This egg tooth then falls off at the same time the baby snake sheds its skin for the first time.
Eggs have to be kept warm in order to survive. Female snakes, with the exception of the king cobra, do not build nests for their eggs.
They usually search for warm holes, burrows or dips in the ground for a good place to deposit their eggs. Some snake species guard their eggs, while others just lay and leave.
A 2018 study of the Southern African python found that mothers warm their eggs by wrapping around them. They then protect and warm their hatchlings for two weeks.
Some female snakes lay eggs without needing a male to fertilize them. This is a process called parthenogenesis.
One species, the brahminy blind snake (Indotyphlops braminus) is entirely female. Other species use both parthenogenesis and the conventional way.
At first, it was thought that some snake species only resorted to parthenogenesis when there weren’t any males around.
Now, studies of species like pit vipers show that some females use parthenogenesis despite easy access to males. Just why parthenogenesis persists, or even originated in the first place, is unknown.
Viviparous Snakes
Some snake species are like mammals in that they birth live young. The young develop inside of the mother snake.
The mother snake’s body gives nourishment to the baby through a placenta. The mother’s body goes into contractions once the time comes for her to birth her babies.
The number of young depends on the species, but often they can be anywhere from one to 40 babies.
It was once thought that snakes that gave birth to live young were somehow more advanced or more evolved than their oviparous cousins. They are now thought to be just different from egg-laying snakes.
Just how the very first snakes produced their young is unknown.
Some genetic sequencing research suggests that snakes and lizards kept switching back and forth from bearing live young to laying eggs before the majority of species came to be egg layers.
Live-bearing came about, or so the theory goes, because snakes began living in places that were too cold for eggs to survive.
Strictly live-bearing snakes, and not ovoviviparous snakes, mostly live in the northern hemisphere. The European viper lives in the coldest climates where snakes can be found, just north of the Arctic Circle.
Female European vipers can give birth to twenty babies.
Ovoviviparous Snakes
Ovoviviparous snakes form eggs, but instead of laying them outside of their bodies, they retain the eggs until the babies hatch. There is no placenta, so mothers do not nourish the babies from their bodies.
All, or at least most, of the babies’ nourishment comes from yolk inside of the eggs. When the eggs hatch, a mother snake gets contractions and gives birth to the babies.
The eggs are much thinner than those of egg-laying species. Some look almost like a membrane, which can appear like an embryonic sac.
Since this appears as live birth, it was long thought that there were only snakes that laid eggs or snakes that gave birth.
The first use of the word “ovoviviparous” occurred in 1801 according to Merriam Webster.
Still, many books still list snakes now discovered to be ovoviviparous and viviparous. These snakes include the largest snake in the world, the anaconda.
Mother anacondas usually go underwater to birth to their young, which can be as many as 40 babies. Many species in the garter snake family also use this method but give birth on dry land rather than underwater.
There are many biologists that insist that garter snakes are viviparous.
Although this combination of egg-laying and giving birth may seem like a strange way to make babies, ovoviviparity, also called aplacental viviparity, is an often-used survival strategy in many species.
It’s found in some species of insects, fish (including the popular pet guppy), frogs, toads, lizards, rays, and sharks.
When you look at the literature around these creatures, especially sharks and snakes, you’ll find many examples describing them as viviparous and about an equal number describing them as ovoviviparous.
No matter the snake’s method of rearing its young, baby snakes are incredibly cute.
Frequently Asked Questions About Snakes Giving Birth to Live Young or Lay Eggs
Do Snakes Give Birth Through Their Mouths?
Many people mistakenly believe that snakes give birth through the mouth, perhaps from sewing mother snakes carrying babies in their mouths. A female snake gives birth through a body called a cloaca, an opening on the belly near the end of the tail.
Do Snakes Need Males to Lay Eggs?
Not all snake species need males in order to reproduce. Commonly called virgin births, parthenogenesis is still largely not understood in snakes. This is the way that the brahminy blind snake (Indotyphlops braminus) reproduces.
Are Snakes that Give Birth More Evolved Than Those That Lay Eggs?
Snakes that give birth are not somehow more advanced or more evolved than those that lay eggs. Individual snake species evolved to best survive in the situations they have to live with. It is unknown if the first snakes laid eggs or gave birth.
The Least You Need to Know
Most snakes lay eggs. Some give birth. Others use a process called ovovivparity, where very thin eggs are deposited inside of the mother snake. The babies grow inside of the eggs and hatch inside of the mother. Then, she gives birth.