There’s a lot of confusion as to whether snakes lay eggs or give birth to live young. Well, snakes can be oviparous, viviparous, and ovoviviparous. This means that some snakes give birth to baby snakes while others keep eggs inside their bodies or lay eggs in clutches.
Approximately 70% of snakes are oviparous, meaning that they lay eggs. Examples include milk snakes, corn snakes, and pythons. Species, such as rattlesnakes, are ovoviviparous. They keep their eggs inside of their bodies until they hatch. Other species, such as garter snakes and boa constrictors, are viviparous. They give birth to live babies, nourished by a placenta.
We’re going to look at the different types of reproduction methods in snakes. You’ll find out which species of snakes lay eggs, and which snakes give birth to live young. You’ll also discover how many babies snakes have each time, and how they protect their young from predators in the wild. Snakes that give birth without laying eggs leave their young to survive on their own.
Do Snakes Lay Eggs or Give Birth?
Snakes lay eggs and give birth, but it depends on the species. Around 70% of snakes are oviparous, meaning that they lay eggs. Most of the species you’ll be familiar with reproducing in this way.
Many species are ovoviviparous or viviparous, meaning that they give birth to live young.
“Oviparous” means egg-laying. Snakes born from eggs are the most common.
The female of the species produces undeveloped egg cells, called ova, in her ovaries. After mating, some of these become fertilized.
The fertilized ova begin developing in the oviduct. A protective shell forms around the outside of the eggs, preparing them for the world.
Unlike bird eggs, this shell is soft and feels like leather. A yolk develops inside the egg, which will serve as the baby’s source of nutrients while it’s growing. While this is happening, the female is said to be “gravid” (pregnant).
Usually, the mother snake is gravid from anywhere between 4-6 weeks, though it does depend on species. She will then lay the eggs in a location which she deems secure.
In the wild, it would be somewhere secluded, away from potential predators. Captive snakes usually choose a hide box.
Once the eggs are laid, the babies start to grow inside their shells. After approximately two months (again, it’s species-dependent), the eggs will hatch. The babies cut a small hole in the egg using a specialized “egg tooth,” which eventually falls off.
Once the babies come out of their eggs, they are on their own. Baby snakes are precocial, meaning that they can survive independently upon entering the world. They must start hunting straight away.
“Ovoviviparous” snakes still produce eggs. However, these eggs stay within the mother until they are ready to hatch.
The reproductive cycle of ovoviviparous snakes starts in much the same way as oviparous snakes. The ova are fertilized and begin to develop inside the oviduct. They grow a protective shell, and a yolk from which the babies absorb nutrients.
However, the mother does not lay the eggs outside of her body for the babies to finish developing. She keeps them inside her until the babies are fully developed and ready to enter the world. The young snakes hatch out of their eggs while still inside their mother, and she then gives birth to them.
In ovoviviparous snakes, the babies do not receive nutrients directly from their mother through a placenta. The mother uses her body as a safe place for the babies to develop.
Consequently, ovoviviparous snakes are gravid for much longer than oviparous snakes. Some species can remain pregnant for up to five months before the babies hatch.
“Viviparous” means live-bearing, and it is the way in which most mammals produce young, including humans. A small number of snake species are viviparous, which is highly unusual for reptiles.
The reproduction process begins in the way that we’re familiar with. Once the ova are fertilized, they begin to develop. However, in viviparous snakes, there is no egg at all. Rather than growing inside eggs, the babies develop inside soft sacs, linked to a placenta via an umbilical cord.
During development, the babies receive nutrients from the placenta, the same way that mammalian babies do. In some viviparous snakes, a yolk sac is also present alongside the placenta.
When the babies are fully developed, the mother gives birth to them as ovoviviparous snakes do.
What Snakes Lay Eggs?
You know how the three types of reproduction work. Let’s explore which snakes fall into each of the three categories. We’ll start with oviparous snakes.
Because so many species fall into this category, we’ll focus on some of the most common pet snakes, and American wild snakes.
1) Rat Snakes
Rat snakes are a common type of snake found throughout the US and are often also kept as pets. They are not one singular species, but all reproduce in the same way.
Two of the most common species of rat snake include corn snakes and black rat snakes (also known as black snakes).
In the wild, rat snakes usually mate in the spring, after they come out of brumation (the reptilian equivalent of hibernation).
Typically, the female is gravid for around four to five weeks. She then lays a clutch of around 12 to 20 eggs, which hatch around two months later. Rat snakes, like most oviparous snakes, abandon their eggs as soon as they lay them.
2) Kingsnakes and Milk Snakes
Kingsnakes and milk snakes form the genus Lampropeltis. There are many different species within the group, though they all have certain things in common. They are all native to the Americas and usually have distinctive colored bands. And, of course, they are all oviparous.
Most kingsnakes and milk snakes follow a similar mating pattern to rat snakes. They brumate in the winter and become active again in the spring.
They mate around May, though this may vary slightly. Most species of milk snakes lay between 5 and 20 eggs per clutch, with an average of about 10. They lay their eggs about six weeks after mating, and the eggs take around two months to hatch.
3) Hognose Snakes
There are four species in the genus Heterodon, but the most commonly recognized are the Western and the Eastern hognose snake. Known for their distinctive upturned “snout,” they are found across the US and northern Mexico. They are favorite pets due to their small size and reluctance to bite.
Hognose snakes also lay eggs. Like most other American snakes, they brumate over the winter months and mate in the spring. Western hognose snakes tend to mate slightly earlier in the spring than their Eastern cousins.
After being gravid for around 4 to 6 weeks, hognose snakes lay their eggs in the summer. They lay between 4 and 30 eggs per clutch, though Eastern hognoses tend to lay more than Westerns. The eggs hatch in 6 to 8 weeks.
4) Gopher Snakes
Gopher snakes, genus Pituophis, are some of the most common snakes found in North America. They include bull snakes and pine snakes and are often mistaken for rattlesnakes, though they’re nonvenomous. Many people also keep gopher snakes as pets, despite their often feisty personalities.
Wild gopher snakes, again, mate in the spring. Gopher snakes are gravid for around 6-8 weeks. Depending on species, they may lay between 2 and 25 eggs at a time, though 12-14 tends to be the most common. The eggs will hatch in around 7 to 10 weeks, in the summertime.
Pythons are native to Africa, Asia, and Australia. They also make up some of America’s favorite pet snakes. Ball pythons, Burmese pythons, reticulated pythons, and carpet pythons are some of the most popular members of the Pythonidae family. Like most species of snake, pythons are also oviparous.
Most species of python do not brumate. This is because they come from warmer climates where the winters are not cold enough to necessitate this behavior. They tend to lay their eggs slightly earlier in the year than American species; around February to April.
The number of eggs varies dramatically with species. Ball pythons will lay between 3 to 13 eggs, whereas reticulated pythons can lay between 20 and 80 per clutch.
How Do Snake Eggs Get Fertilized?
The majority of snakes are sexual creatures. To reproduce, a male and a female snake must come together and mate.
The ova (female reproductive cells), which eventually turn into eggs, develop inside the female’s ovaries. The male reproductive cells (sperm) enter the female’s body through copulation.
A male snake has two hemipenes (penises) that he usually keeps inverted, inside his tail. When ready to mate, these hemipenes will evert through the cloaca (the genital and anal opening).
They then enter the female’s cloaca and deposit sperm. The sperm fertilizes the ova, which go on to develop into eggs.
Sometimes, not every “ripe” egg will get fertilized. When this happens, the female snake will lay some unfertilized eggs along with the healthy ones.
They can be distinguished from the other eggs by their appearance. Viable snake eggs are large, white and leathery; infertile eggs are smaller, yellowish and hard. Snake breeders often refer to infertile eggs as “slugs.”
How Do Snakes Mate?
Snakes mate through copulation (sexual intercourse). It happens once or twice a year. In American snakes, this is almost always in the spring, after coming out of brumation.
This is how the snake mating process works:
- When a female snake is ovulating, she will release pheromones from special scent glands. These inform male snakes that she is ready to mate.
- If a male snake catches this scent, they will follow the trail until they find her.
- The male will “court” the female. The courtship rituals vary between species, according to a study in PLOS One. Some snakes move their bodies in rhythmic ways or vibrate their tails. Others will bite the female’s neck, or rub their chin on her head. Snakes with pelvic spurs, such as boa constrictors, may rub them on the female’s back to stimulate her.
- The female will raise her tail to indicate that she is receptive. Then, the male will intertwine his tail with hers, until their cloacae meet. The male’s hemipenes will come out of his cloaca and enter the female’s.
- Once mating is complete, the male deposits a sperm plug inside the female’s reproductive tract. This will make it more difficult for other males’ sperm to reach her eggs.
Sometimes, multiple snakes will find the female at the same time. When this happens, it can create a “mating ball,” where many males compete to try to mate with the female. Garter snakes are particularly famous for their large mating balls.
Can Snakes Have Eggs Without Mating?
Some species of snake, such as rattlesnakes, can store sperm inside their bodies for later use.
According to the Biological Journal of the Linnean Society, they may store it for up to five years. This would allow eggs to become fertilized without the snake having mated for a very long time.
Though they are rare, some species can also produce viable eggs without having mated at all. An unfertilized egg, containing only the mother’s DNA, develops into a healthy baby snake.
This is called parthenogenesis and is very rare in snakes. One example of a snake which reproduces this way is the Brahminy blind snake, a tiny snake native to Africa and Asia. Every member of the species is female, and babies are genetic clones of their mothers.
Where Do Snake Eggs Come Out Of?
After fertilization, the female then keeps the eggs in her body until she is ready to lay them. Before they are laid, the eggs must first develop:
- A yolk, full of nutrients for the baby snakes to feed on while they’re growing inside the egg
- A protective outer shell for the babies to develop inside of.
Once the eggs have developed to the point that they can survive outside of the mother’s body, they will make their way down her reproductive tract, and eventually exit through her cloaca. One egg comes out at a time. The laying process may take several hours in total.
Do Snakes Lay Eggs Through Their Mouth?
Occasionally, we hear people claim that snakes lay eggs through their mouths. This is untrue. Snake eggs come out from the same place where the sperm went in: the cloaca.
We aren’t sure exactly where the myth of snakes laying eggs through their mouths comes from. However, we do know that many species of snake feast upon bird eggs as part of their natural diet (such as rat snakes and bull snakes).
Snakes often regurgitate their food if they are threatened by a predator shortly after having eaten. Losing the extra weight helps them to make a quick getaway. It’s possible that people have witnessed this happening to wild snakes, and assumed the snake was “laying eggs.”
How Many Eggs Do Snakes Lay at One Time?
Usually, snakes will only lay one clutch of eggs per year. However, some species (particularly those which can store sperm for later use) may lay two or even three clutches. How many eggs the snake lays per clutch will vary depending on the following:
- The size of the female: larger females can produce more eggs
- The age of the female: generally, the first clutch is the smallest
- Food availability: females who eat and drink more will usually produce more eggs
- Individual differences: some individual snakes are genetically predisposed to larger or smaller clutches
- If the female has more than one clutch per year, the first clutch will probably be the biggest.
Depending on all of the above factors, a clutch may consist of 2 eggs or 80 eggs. It’s typically somewhere in between (6 – 25).
Reticulated pythons tend to lay the most eggs at once, primarily due to their extreme size. An example of a snake which lays very few eggs at a time is the Sonoran coral snake. Clutches are usually 2-3 eggs.
How Do Snakes Protect Their Eggs?
Most snake species do not exhibit maternal traits. For the vast majority of oviparous species, the eggs are abandoned as soon as they’re laid. The most that the mother snake does to protect her eggs is to find a secure, secluded spot in which to lay them.
In captivity, this will usually be a “hide box” provided inside the vivarium. In the wild, she would try to find a spot that is away from predators. Once the last egg has been deposited, she will abandon the eggs, never to return.
However, this is not the case for all snakes. Most pythons, unlike many other species, actually incubate their eggs. Once the entire clutch has been laid, the mother coils her body around it, and vigilantly defends it.
Often, she will not leave her eggs until they hatch, going without food for the duration of their incubation. This serves two purposes:
- It helps the eggs to maintain the correct temperature for development
- It eliminates the chances of her eggs being eaten by predators.
Most pythons will leave once the babies hatch, though the African rock python guards her babies for up to two weeks afterward.
Which Snakes Give Birth to Live Babies?
Now that we’ve covered everything there is to know about oviparous snake species, let’s have a look at the odd ones out. Around 30% of snakes that we know of give birth to live young.
Some produce eggs and incubate them inside the body until they hatch (ovoviviparous species). Others grow their young without the use of eggs, nourishing them through a placenta, just like us.
The infamous rattlesnakes, found in abundance across the Americas, are ovoviviparous. They produce eggs, but they do not lay them.
Once the ova are fertilized, they pass from the ovaries into the oviducts, which are like long rather than laying them, they keep their eggs inside the body. This provides the ultimate protection from predators and the cold.
Rattlesnakes are usually pregnant for around three to five months, giving birth in the late summer. When the babies are fully developed, they will begin to break out of their eggs, and the mother will give birth to them.
There are usually around 10 – 20 babies born at one time, though this varies by species. They are born encased in a very thin membrane which the babies soon break out of. The young stay with their mother in her den for just over a week, before heading into the world alone.
2) Copperheads and Cottonmouths
Copperhead snakes and water moccasins (cottonmouths) belong to the same genus, Akistrodon. Found in Southeast US, they are part of the same subfamily as rattlesnakes – the pit vipers.
Therefore, they have a very similar reproductive system. Like rattlesnakes, they are ovoviviparous, keeping hold of their eggs inside their bodies until they reach full term.
Copperheads and cottonmouths usually have fewer babies than rattlesnakes. Cottonmouths typically have 6-8 babies per litter, whereas copperheads have between 4 and 10.
You can identify baby copperheads and cottonmouths by their bright yellow-green tail tips, which they use to attract frogs by mimicking worms.
According to a study in Biology Letters, copperheads and cottonmouths are two of the rare species of snake which can reproduce asexually, through parthenogenesis.
3) Garter Snakes
Garter snakes are a common species of wild snake. They can be found across the country in almost every state, make up a variety of different species in the genus Thamnophis.
Rather than being ovoviviparous, garter snakes are viviparous. This means that they do not develop inside eggs at all. Garter snake babies grow inside their mothers, encased in a thin, cellular membrane, rather than a calcified eggshell.
A yolk is still present, but developing young receive most of their nutrients through a placenta, which is connected to the mother.
Between 3 and 80 garter snakes are born at a time, depending on species. Unlike pit vipers, baby garter snakes leave their mother as soon as they’re born.
4) Boa Constrictors
Like garter snakes, boa constrictors are also viviparous. They are gravid for around four months, during which time the babies develop fully inside the mother’s oviducts.
The average litter size in boa constrictors is around 16, though they can have up to 50 babies at a time in rare circumstances.
The young are born inside very soft, transparent cellular membranes (similar to human amniotic sacs), which they break free from immediately.
Some even manage to break out before they are born. The babies tend to stay together for a while before making their way into the world as individuals.
5) Sea Snakes
Sea snakes, of the subfamily Hydrophiinae, are unique among serpents. They spend their time in the water, and most species cannot move on land, though they must come up to the surface to breathe.
All sea snakes are venomous and belong to the family Elapidae, which also contains coral snakes. However, unlike coral snakes, most sea snakes are viviparous.
This is probably due to the high risk of eggs being consumed by marine animals. The only exception is the sea krait, which comes onto land to lay its eggs.
How Many Baby Snakes Survive?
Snakes are a precocial species: when the young hatch (or are born), they are almost fully developed. They are born with all of the senses, instincts, and movement abilities of adult snakes.
The young of venomous species, such as copperheads, are born pre-loaded with venom and fully developed fangs.
This is a good thing as it means that the babies have a good chance of surviving until adulthood. They can defend themselves from the outset and escape predators.
Unfortunately, not all of them will make it. Some may be picked off by predators while they are still very small; others may fail to grow large enough to survive the winter.
The survival rate of wild juvenile snakes can only be guessed at. This is because it’s difficult to capture and analyze wild snakes, and impossible to do so without interfering with their lives.
Some people guess that between 10-25% of snakes may survive until adulthood. However, an article published in the Ecology journal suggests that the figure may be much higher.
As soon as juvenile snakes reach adulthood, they will become sexually mature. They usually reach this point between age 2 and 4, dependent upon species. At this point, they will have the ability to mate, and the reproductive cycle will start again.