If you’re interested in reptiles, you’ll want to know more about how snakes reproduce. Perhaps you want to breed a pair of snakes or want to find out if snakes reproduce sexually or asexually. The entire breeding process of snakes remains something of a mystery to most people.
Most snakes reproduce sexually, but some reproduce asexually. They mate in the spring after hibernation, using pheromones to attract mates. A male snake mates with a female snake by inserting one of his hemipenes into the female’s cloaca. This fertilizes the eggs inside her oviduct. A month after, she lays her eggs, which hatch two months later. Other species, such as boas, give birth to live young.
We will look at everything you need to know about the reproduction cycle of snakes, from snake sex organ anatomy to how snakes form eggs. The female with the strongest pheromones is considered the healthiest. Male snakes will mate with multiple female snakes during their lifetime.
- 1 The Snake Reproduction Cycle Explained
- 2 When is Snake Mating Season?
- 3 How Do Snakes Get Pregnant?
- 4 How Do Snakes Give Birth to Eggs?
- 5 Snake Mating Issues
The Snake Reproduction Cycle Explained
Snakes don’t have reproductive organs. In fact, from the outside, snakes don’t display sexual dimorphism. This is the term that refers to the visual differences between the sexes.
In humans, men and women are different shapes and sizes, have different organs, etc. In snakes, you can’t tell the difference between male and female snakes from the outside.
This might seem interesting but of little consequence. It’s a crucial point. As a snake looking to mate, how can you tell who’s male and who’s female? And how can you know which end of a snake is which? The journal Behaviour sought to answer this question.
They found that snakes use a combination of pheromones, that a male detects when he discovers a female. To mate, a male snake presses his chin onto the female’s back.
He then runs up along her back, all the way to her head. In doing so, he picks up the pheromones that tell him that she’s a female. They then perform a ‘cloacal kiss,’ and mating is achieved.
Male Snakes vs. Female Snakes
Male snakes have two organs called hemipenes. These are like the snake’s penis, and it has two which are kept inside the cloaca.
They’re held in place by the retractor muscle. When reproduction occurs, the two hemipenes are ‘everted,’ which means that they pop out of the cloaca. They also have testes inside their bodies, near their other organs, unlike ours which are on the outside.
The female snake, like all snakes, has a cloaca. However, female snakes have ovaries that produce eggs, which males don’t have. They also have an oviduct, which is where the reproductive eggs develop into the eggs that she lays.
In many species, the female is also larger than the male. According to the Proceedings of the Royal Society, different reproductive roles favor different body plans.
They found that male and female snakes have different bodies in many ways that you can’t see:
- In female snakes, the organ systems that store energy are enlarged. This includes the digestive tract, the liver, and places where they store fat in their body. These stores give them additional energy for when they have to develop their egg because doing so requires more energy than they can get from feeding.
- Male snakes have enlarged skeletal muscles, larger tails, and better functioning kidneys. The scientists suggested that this would help them when searching for a mate, when fighting with other males, and in creating stronger sperm.
The scientists dissected 243 specimens from three species, including two colubrids and a viper.
What is the Cloaca?
The cloaca is a unique part of a snake’s anatomy. It’s shared by snakes, all other reptiles, amphibians, birds and a few mammals, and is used for both excretion and mating.
It’s a part of the snake’s basic anatomy. If you were to stretch a snake out on a table, the first 25% of the snake is the brain, the trachea and esophagus, and the heart.
The next quarter contains most of the bodily organs, including the stomach. The final two quarters contain the small and large intestines.
That’s because snakes digest food. And when a snake excretes anything they’ve digested, they get rid of it just like humans. That’s the purpose of the cloaca.
According to ResearchGate, the cloaca is made up of three distinct parts:
|Coprodeum:||This part collects feces from the colon. It is the first and largest section of the cloaca.|
|Urodeum:||This part collects urine and any products of reproduction.|
|Proctodeum:||This part excretes any waste.|
The female cloaca is shallow, compared to the male’s, which is longer and extends further down the tail. This is because the male’s cloaca contains the two hemipenes.
These have to be contained inside, or they would drag along the floor behind the snake, which would damage them. All mating in snakes is done using the cloaca and hemipenes.
When is Snake Mating Season?
Snakes emerge from hibernation in the spring, which is when mating begins. Snakes in northern, colder climates go into full hibernation.
This is an extended period of almost complete sleep. Snakes in the south, though only go through brumation. This is similar to hibernation but slightly more active. Once a snake emerges from either hibernation or brumation, only then do they start mating.
The reason for this timing is that snakes are ectotherms. That means that they can’t produce body heat (cold-blooded.)
Not only does this make winter a dangerous time to be a snake out in the open, but it means that it’s harder to lay and protect eggs.
If a snake were to lay eggs at the wrong time of year, both she and her clutch would have difficulty staying warm. Spring and summer are the ideal time, and snakes usually lay one clutch per year.
Depending on the species, it can be either the male or female who emerges from hibernation/brumation first. Once the female snake emerges, she can start attracting mates.
How Do Snakes Attract Mates?
Snakes attract mates using pheromones, just like many other animals. Female snakes produce estrogen, and it plays a significant role in snakes attracting mates.
A study in the Journal of Experimental Biology found that by boosting a male snake’s estrogen, they would naturally start to produce new and exciting pheromones.
These pheromones were the same as produced by a female snake. This confused the garter snakes in the study so that they would start trying to mate with the male.
Garter snakes rely entirely on pheromones to facilitate mating. This is so much the case that the male must first lick the female to determine which pheromones and chemicals they give off. They use a sixth sense that’s similar to smell, but more focused on specific pheromones.
It’s called the vomeronasal system, and it’s sensitive. It’s the same system that dogs have. Humans have one too, but it’s not as powerful, and it’s unclear what role it plays in our sense of smell.
Either way, with just with one quick flick of the tongue, a snake can figure out the species, sex, reproductive condition, size and even age of their potential partner.
Do Snakes Mate for Life?
It’s rare for an animal to mate for life, and snakes are no different. Male snakes are attracted to the most viable female based on their pheromones.
The female snake that creates the best-smelling pheromones is probably the healthiest, so that’s the one they’ll opt for. Once the two snakes’ mate, the male doesn’t usually stay. They go on to find other females, but there are exceptions to every rule.
According to the Royal Society journal, males of some species protect the female they’ve mated with to stop them from mating with anybody else.
Not only that, but females that have already mated become less attractive to males, at least according to a study on red-sided garter snakes.
There’s also another aspect to snake mating that prevents the snake from have multiple mates that have nothing to do with loyalty and love. Male snakes can produce what is called ‘mating plugs.’
Once the male has mated with the female, he can produce a gelatinous plug—basically, like a cork. The mating plug blocks up the female’s cloaca and stops any other males from being able to mate with her in that breeding season.
This behavior evolved because it makes the male who produced it more likely to have offspring. That being said, the two won’t stick together next breeding season.
How Do Snakes Get Pregnant?
So, how does a snake fertilize an egg? Snakes mate by aligning themselves with one another, the male moving up along the female’s body.
He then inserts one of his hemipenes into the female’s cloaca. This is called the cloacal kiss because the two cloacae come into contact with one another.
Most snakes’ hemipenes have ridges and spikes that perfectly fit the female cloaca, to avoid slipping or otherwise moving away.
This aids in reproduction, but also prevents interbreeding between different species of snake. It takes quite a while for snakes to mate, usually between an hour and a whole day.
Sperm in snakes is produced, like in other animals, in the testes. These are located inside the body cavity, near the stomach and liver.
The sperm travels along a duct, through a ridge in the hemipenis and into the female’s cloaca. Again, like other animals, this sperm fertilizes the female’s eggs, which is how they get pregnant.
How Do Snakes Mate?
It starts when the female snake releases pheromones from glands on her back. The location of the glands on her back means that she leaves a trail of pheromones behind her, wherever she goes. The male finds the scent, follows the trail, and finds the female.
When the male finds the female, he slides his way up her body. In some cases, he may wrap himself around her to make it more difficult for her to get away. He keeps his head low against her back as if feeling his way. Once he reaches her head, he bumps his chin into it over and over again.
At this point, the male then wraps his tail around hers to find her cloaca. At this point, his hemipenes will be extended. Once he finds the cloaca, mating may last many hours.
Afterward, the male will release a ‘mating plug.’ Mating plugs are like the corks we put into wine bottles. The point is to make it impossible for any more males to mate with the female during that breeding season.
They’re so crucial that male snakes can use up to 18% of their daily energy to make one, leaving them hungry and weaker in the process.
Snake Mating Ball
Snakes can mate in a unique shape called a mating ball. It’s so-called because dozens of snakes appear to be a big, writhing mass. This strange mating method is unique to snakes and can be unnerving to see in person. It occurs when many males want to compete for the same female.
Believe it or not, but inside this ‘mating ball,’ there may be dozens of males all competing for the attention of just one female. Why do snakes mate in a ball?
Because only the strongest, fastest, and fittest snakes will be able to reproduce, this ensures that babies are most likely to be strong like their parents. This is the basis of natural selection.
That being said, some snakes have figured out ways to cheat the system. Some male snakes have learned to disguise themselves as females, through secreting scents usually associated with females ready to breed—just like the study described above.
The theory goes that this catches out the first males to try and mate so that the pretend-female then gets a better chance to mate with the female.
Do female snakes eat the male after mating? Not always, but sometimes they do. Green anacondas in Brazil do. Records of a trek published on National Geographic include a fantastic picture.
It shows a female, as thick and wide as a truck tire, constricting her mate. The writers thought that it could be because the male is a good source of protein and nutrients to an expecting mother.
However, you’re not likely to see this behavior at home. Nor are you likely to see a mating ball, because you shouldn’t keep snakes together. The only time that snakes should be able to mate in your care is if you would like them to, and you put them in the same enclosure.
Snake Asexual Reproduction
If your snake laid eggs without mating, this isn’t an issue. It’s rare, but it does happen.
Snakes are one of a small group of animals that can reproduce asexually. The flower pot snake is an example. The females of the species can produce young through a process called parthenogenesis.
In doing so, they can create clones of themselves. Depending on the exact scientific process, these can be referred to either as full clones or half-clones, depending on the amount of genetic material inherited by the young.
A study in the journal Biology Letters looked at the issue, specifically in North American pitviper snakes (including the copperhead and the cottonmouth).
Both of these species can reproduce asexually. However, if you notice this at home, it may also be the result of delayed breeding. It’s possible for a female to store sperm in her cloaca for up to six years, and that sperm remains viable. She might therefore suddenly become pregnant after you bought her (provided that she was old enough at the time).
Alternatively, your snake may have laid eggs without mating or reproducing asexually. These eggs will be unviable. There won’t be any babies in them. This is the case even if the snake does mate since at least one or two of the eggs usually don’t hatch.
Can Snakes Mate with Themselves?
No, a snake can’t mate with themselves. This is a misconception. Snakes can reproduce asexually, but that doesn’t mean that they’ve mated with themselves.
Mating refers specifically to the act of two animals breeding, ordinarily male and female, but occasionally hermaphroditic animals (e.g., slugs and snails).
Certain animals can ‘mate’ with themselves. The same applies to plants. Plants can pollinate their own flowers, and in so doing, reproduce a perfect clonal copy of themselves.
There’s even a small flatworm that can have sex with itself, using both sperm and eggs. However, this doesn’t seem to be the way that asexual reproduction works in snakes.
Can a Snake Mate with Another Snake’s Species?
Snakes of different species have differently shaped hemipenes and cloacae. In a way, they’re reminiscent of keys and locks. A key that is used to unlock the wrong kind of lock won’t work.
However, as always, nature isn’t simple in that way. It’s most definitely possible for two different species to breed. It all depends on what you mean by different ‘species,’ and to unravel that idea, we have to go back to basic biology.
In biological classification, there are eight significant levels. At the bottom are the species. Then, moving upwards, we have a genus, family, order, and class. Let’s take the corn snake as an example:
- Species: Corn snake. This is the corn snake itself, defined by its colors and habitat. It’s unique among snakes.
- Genus: Corn snakes are in the genus Pantherophis, also known as rat snakes. There are about a dozen different rat snakes. They’re all constrictors that eat rodents.
- Family: Corn snakes are Colubrids, a big group which contains Pantherophis and other families.
- Suborder: Corn snakes are in the suborder Serpentes, which contains all snakes.
- Order: Corn snakes are in the order Squamata, which contains most lizards and reptiles.
- Class: Corn snakes are in the order Reptilia, containing all reptiles.
Breeding two snakes of the same subspecies together is not a problem. That means that having two varieties of corn snake breed is fine.
Corn snakes are almost unique, though, in that they can breed with a startling number of other species from the same genus, even the same family. They can interbreed with:
- California Kingsnakes. When a corn snake mates with a California Kingsnake, they create what’s been termed a ‘Jungle Corn.’ This hybrid snake is variable in appearance but is also quite healthy.
- Gopher Snakes. A hybrid between a gopher snake and a corn snake is called a ‘Gopher Corn’ or a ‘Turbo Corn.’ They have keeled scales, which means that they have a ridge running along their back down the center of their scales.
- Great Plains Rat Snakes. A hybrid between an albino corn snake and a Great Plains Rat Snake is called a ‘Creamsicle Corn.’ After two generations, these snakes are a yellow-orange color, hence the name.
The unusual thing is that these hybrid snakes are, themselves, fertile. This is not usually the case. Take the offspring of a lion and a tiger (they produce a ‘liger.’)
According to a biological rule named Haldane’s rule, when two species interbreed, the males are generally sterile. Ligers follow this pattern, but corn snake hybrids don’t.
How Do Snakes Give Birth to Eggs?
Some snakes give birth to eggs, and some snakes give birth to live young. Corn snakes, for example, lay eggs. Sea snakes, by contrast, give birth to live young. There are three different kinds of snakes:
- These snakes give birth to eggs. Around 70% of snakes are oviparous, as are the vast majority of Colubrids (the most common snake family).
- These snakes are like a mix between oviparous and viviparous snakes. They develop the eggs within their body, but the eggs hatch inside her. She then, effectively, gives birth to live young. Rattlesnakes are ovoviviparous.
- Viviparous snakes give birth to live young, and at no point is there an egg involved. The young develop inside a placenta and yolk sack. This is the most similar process in reptiles to what we mammals do. Boa constrictors are viviparous.
If we’re talking about oviparous snakes, after mating, the snake will find the perfect place to lay her eggs. This is called oviposition. The location has to be sheltered so that it doesn’t get too cold.
The development of the eggs takes place within the female herself. Either way, the snake pushes her eggs out from her uterus and through the cloaca, using muscle contractions, as we do.
The eggs are pushed out one after the other, steadily, until the female has birthed them all. The eggs stick together so that they can’t roll around, which might damage the baby snakes inside.
After they give birth, the vast majority of female snakes then abandon their eggs. However, some do stay with their eggs to protect and warm them. Pythons are an excellent example.
Online, it’s easy to find videos of what appear to be snakes giving birth through their mouths. This doesn’t happen. This is a misconception.
The snakes aren’t giving birth to the eggs. They had to regurgitate something that they’d eaten! They aren’t the snake’s eggs, but probably the eggs of a bird whose nest they’ve raided.
How Do Snakes Make Eggs?
The process of making eggs is quite complicated. Most of it takes place in the oviduct, which is the tube that connects the ovaries with the uterus.
The eggs are released from the ovaries, and as they travel to the uterus, are coated with special secretion. In combination with protein fibers released in the uterus itself, they create the egg’s shell.
This is different from chicken eggs for example. Snake eggs are more uniform throughout, whereas other kinds of eggshell have several layers made from different materials.
Not only that, but chicken eggs (and other similar kinds of eggs) are primarily made from calcium carbonate crystals. According to a paper in PLOS One, snake eggs only have a superficial coating of these protective, semipermeable crystals. This gives the eggs a different feel to ‘normal’ eggs. Instead of being brittle and thin, they’re leathery and thick.
Like all animals, the eggs then gestate until they’re ready to be birthed. This takes many weeks, throughout which the eggs develop, becoming larger. The snake will naturally know when they’re ready to birth them.
How Long Does It Take for a Snake to Lay Eggs?
From the moment of mating until the eggs are laid, the process typically takes about 30 to 45 days. Eggs and young take a long time to develop, whether the snake is big or small. Among animals, snakes have a relatively short gestation period.
If your snake is pregnant and you’re waiting on them to give birth, there’s a sign that they’re closing in on their due date (apart from the fact that they’re getting bigger around the middle).
About four weeks after mating, your snake will start her prenatal shed. This is just like any other shed, but it’s a useful marker for when she’s about to begin birthing her eggs or young.
From the moment they start birthing, it usually takes a pet snake 24 hours to lay all of their eggs. Generally speaking, the smaller the snake, the fewer eggs they’ll lay.
The largest constrictors lay up to 100 eggs each time they birth. However, just like any other animal, birthing isn’t always without its problems. It’s possible for your snake to become egg-bound, meaning that there’s a particular egg that’s too big or too broken to birth.
If it takes your snake more than 24 hours to pass an egg, take her to a veterinarian. They can use a variety of techniques to help her pass the eggs more quickly, including mineral oil.
Don’t attempt to do this at home, as it could kill your female if you don’t know what you’re doing.
Snake Mating Issues
Mating and reproduction, as in all animals, don’t always go perfectly. Many issues may present themselves long before any eggs hatch. Let’s take a look at what they are, and what causes them.
1) Death of the Female
Mating in snakes can cause the death of the female. This can be due to many reasons. A paper in the UK’s Royal Society journal discussed a few of the reasons why this might be the case.
- After mating, the development of so many eggs can cause malnutrition in a female snake. Snakes only eat occasionally as it is, so if a female snake can’t find any food, she stands a chance of starving. After all, she can’t stop her eggs from developing.
- Carrying eggs also leaves a snake more open to predation. This is because she may be weaker, slower, and malnourished. When she’s trying to fight a predator or escape as fast as she can, carrying eggs could be her downfall.
- A female snake can also get sexually transmitted diseases, or become ill because of the stress of being pregnant. Snakes are vulnerable to parasites, viruses, and infections.
Inclusion body disease is an excellent example of the viruses that can affect snakes. Until relatively recently, nobody knew what this new problem was.
One day, your snake would be healthy. The next, they would have breathing problems, paralysis, and be stuck ‘stargazing’—staring upwards at nothing. This is caused by a problem called Inclusion Body Disease, or IBD. This isn’t a sexually transmitted disease per se, but it can be passed from snake to snake through physical contact.
Of course, these problems are more prevalent in wild snakes than those in captivity. As a pet, there’s no chance that a snake can be predated upon, and there’s no chance that she can starve unless you choose not to feed her.
There’s also no chance that your snake will come into contact with another unless you house them together. You also have to make sure you wash your hands immediately after you handle any snake or reptile, to prevent infections and parasites being spread.
That’s why snakes in captivity can live between 20 and 30 years, whereas they would never reach that age in the wild due to predation.
2) Egg-Bound Snake
Female snakes can become egg-bound, which means that they struggle to birth their eggs. The egg, having become stuck, can then cause complications.
It causes the death of any eggs/young that she cannot birth can scar and damage the reproductive tract and can result in the death of the female. There are many causes of egg-binding in snakes:
- If the snake is immature or small, she may not be large enough to birth the egg.
- The snake may have a defect that blocks her reproductive tract.
- The egg may be abnormally large or might be a strange shape. There is also the chance that the egg may have broken and cracked.
- The female may have malnutrition, in which case her muscle tone is reduced.
- Additional causes include hormonal issues, disease, dehydration, and overcrowding. Essentially, anything that causes stress or over-competition.
If your snake is egg-bound, you must take them to a veterinarian. If you try to fix the problem yourself, you can cause them even more damage. However, if you leave the issue alone without trying to fix it, there’s a chance that the egg-bound female could die.
3) Hemipenis Prolapse
The prolapse of either one or both of the hemipenes is a rare occurrence, but it can happen. It’s usually the result of a general injury to the snake’s tail, but it can also occur after irritation or inflammation, neurological issues or specific damage to the retractor muscles which typically hold the hemipenes in place.
If the hemipenes prolapse, they sit outside the body permanently, with the snake unable to pull them back inside their cloaca. This results in swelling, which exacerbates the problem.
The longer the penis is outside the sheath, the more swollen it gets, and the more difficult it becomes to retract. The swelling occurs because of irritation from the ground/other surfaces as the snake moves, as well as the potential for infection.
In cases of swelling, it is possible to reduce them using a mixture of bathing and sugar solutions. If the hemipenes still refuse to retract, you may have to take your snake to a vet.
If you have already tried a sugar solution, the doctor may attempt to use lubrication to return the hemipenes inside the cloaca. In the worst-case scenario, your snake will have to undergo amputation. This surgery means that your snake will survive, but be unable to breed.
If you’re thinking of breeding snakes, don’t make the mistake of thinking that your snakes will take care of the process from start to finish. You have to be prepared.