how do snakes mate
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How Do Snakes Mate?

People either love snakes or run away from them. Aside from their slithering locomotion, we also often ask how snakes mate. These reptiles mainly reproduce in the early summer, right after their hibernation period ends. 

The sight of snakes mating isn't as pleasant as their eye-catching skin. Male snakes fight their way through other contenders to put their penises in the willing female’s opening, the cloaca. 

This article discusses snakes' reproductive organs and the seasons in which snakes mate. We'll also discuss snake courtship rituals and how snakes mate and reproduce. Lastly, we will explore the unique phenomenon of snakes birthing offspring without having intercourse.

Related Read: Snake Facts, Types of Snakes.

What are the female and male snakes' reproductive organs?   

snake closeup
Photo by Andrew Liu on Unsplash.

Snakes have reproductive organs similar to mammals, but some differences remain. Female snakes have a vagina accessible into the cloacal opening through a separate opening in the cloaca. 

The female reproductive tract consists of long, slender ovaries in the same location as the male snake testes. Their oviducts open into the cloaca separately from the vagina without forming a uterus. Female snakes also have clitoris. They are referred to as hemiclitores2.

The reproductive system of a male snake is different. A male snake has two forked hemipenis in a separate inverted position from the hemipenis sac. The hemipenes have grooves or spines that allow them to grip the walls of the female’s cloaca.

The hemipenis sac is at the end of the tail. Each species has varying sizes of hemipenis that allow for easy identification. A male snake also has oval-shaped testes connected to the sperm duct lining the intestine.

When is the breeding season for snakes? 

rat snakes mating
Photo by Sandaru Muthuwadige on Unsplash.

Snakes' mating season mostly depends on the climate of their ecosystem. Most snake species usually breed during the springtime. It is after they wake up from reptilian hibernation during winter. 

Many species, like the garter snakes, prefer mating just as sunlight comes out because that's the peak of their energy. Reproduction during springtime ensures the survival of baby snakes because the eggs hatch in the summer when there is food and sunlight. 

There are multiple mating seasons in ecosystems with conflicting climate systems. For instance, snake species living in tropical and subtropical regions can mate throughout the year instead of a singular mating period. 

Most snakes adapted their mating habits to ensure that baby snakes can grow enough to survive the cold season. Also, their mating habits could depend on the costs of reproduction. 

A female snake will delay reproduction if it requires risky behavior like frequent basking. She often delays reproduction until she can carry a large clutch of eggs. Female snakes usually select the most suitable period to birth little snakes3.

Snake Courtship Rituals  

mating water snakes
Photo by Joshua J. Cotten on Unsplash.

Courtship rituals during the mating season vary among snake species, but some similarities exist.  Males initiate and perform most of the courting actions. A male snake looks for a female snake ready to mate, attempts to woo, and aligns its body to deposit sperm into the female’s cloaca.  

Mating in the boid snake species involves the male snake laying on the female snake while using its vestigial hind appendages to stroke, scratch, or vibrate against her to calm her. The male also tries to get her to twist her cloaca to facilitate mating.

However, the colubrid species have a more complex mating ritual. Male snakes chase the females to mount them dorsally, intertwine their bodies, and bite each other. Coraline species entwine their bodies while the male performs head-jerking movements. Sometimes, he moves his trunk and pokes at the female with his snout.

It is not unusual to find multiple male snakes courting a female snake during the mating season. There's often competition among most males before one successfully mates with a female. 

The males perform a ritual known as topping, where they twist around each other and sometimes bite each other. The male snake that successfully tops the other gets to mate with the female. This practice is common to garter snakes. 

How do snakes mate?

mating ball
Photo by Oregon State University on Flickr licensed under CC BY-SA 2.0 (Cropped from original).

Most snake species mate in a ball- the mating ball or knot. The common garter snake is a prime example of how snakes mate. The female garter snakes wake up from brumation a few days after their male counterparts. The time gap gives the males extra time to prepare for the mating ritual before mating with a female snake. 

Mating is not different among big snakes. Certain species, like the green pythons, prove otherwise, as they form a ball during their mating process.

As soon as the female garter snake appears, the males start fighting for their chance to mate with her. Soon, a mass of male-aggressive snakes surrounds her because of her pheromones. The males fight to get access to and line up their reproductive organs, the cloaca.

As the males fight for their chance in the writhing mating ball, the female decides who she mates with. She notes the notable male that fights well through the ball of writhing snakes.

The male snake gives her an anoxic kiss to induce compliance when she struggles during the mating process. The kiss deprives her of the oxygen, so she can’t struggle. In extreme cases, the anoxic kiss can lead to death.

Once the male snake successfully inserts his two penises and releases his sperm into her, he tries to seal the entrance of her cloaca with a gelatinous secretion that lasts for a few days. The secretion glues the sides of her tract together to prevent other males from releasing their sperm into her. 

The male snakes go their separate ways when the female snake stops emitting pheromones a few minutes after mating. An observation on garter snakes shows that two or more snakes can deposit sperm in the female before sealing her entrance. 

How do female snakes reproduce? 

The sperm fertilizes the eggs in the female snakes. They give birth through three reproductive modes: 

Oviparous 

Oviparous snakes lay eggs. Most species give birth this way. Female snakes prepare a nest when their delivery period is near.  A snake’s nest is usually an underground burrow or a hollow log.

She lays eggs once the nest is ready. Females can lay between one to forty eggs per clutch. Snake eggs are soft-shelled, allowing the little snake to breathe. The eggs also require high humidity to maintain moisture because they won’t hatch under dry conditions. Some snakes stay with the eggs until they hatch, while others abandon the nest.  

Viviparous 

Viviparous snakes give birth to live young and have a shorter gestation period than snakes that lay eggs because the egg hatches inside the snake’s body. They give birth to live young, fully-formed baby snakes without incubation.

Viviparous females mostly live in areas with colder climates because little snakes have a better chance of survival. They also live longer than other snakes that lay eggs, so they reproduce more often. 

Ovoviviparous 

Lastly, ovoviviparous snakes lay eggs and give birth to live young. You’ll find this snake reproduction method in king cobra and green tree python snakes. Ovoviviparous snakes have a shorter life span than viviparous and oviparous snakes because they spend most of their lives reproducing baby snakes.

The little snakes have to fend for themselves as soon as they hatch. As soon as they break through the shell with their forked tongue, they are subject to predators like birds, lizards, and foxes. 

Snake Reproduction Across Various Species  

python's eggs
Photo by David Clode on Unsplash.
  • Pythons lay eggs in a shallow nest, covering them with soil and leaves. They are one of the snakes that protect their eggs during incubation. Mother pythons can raise the temperature of their eggs through a process known as thermogenesis. She contracts her muscles rhythmically to create warmth. This process drains her energy, so she reproduces every two to three years.
  • Boas have multiple mating partners during a mating season. Female boa snakes only reproduce when in good condition, so not all of them reproduce yearly. They prefer to breed during the dry season, from April to August. Female boas give birth to live young after 5 to 8 months of gestation. They birth an average litter of 25 little snake.
  • Rattlesnakes are ovoviviparous- they lay eggs and give birth to baby snakes. They mate and reproduce every two years. Rattlesnakes carry the eggs in a transparent wrapper for 90 days before birthing the litter. The little snake pokes its nose through the membrane to breathe air.
  • Before cobra snakes lay eggs, they build a nest with leaves. They cover the eggs with leaves and sit on them until they hatch. The baby snakes are ready to fend for themselves when they take their first breath. However, they get nourishment from a large yolk sac in their stomachs for a short period. It often lasts two weeks before they hunt for food.
  • Milk snakes mate in the spot they brumate just a little bit before spring. They go their separate ways after emerging from hibernation. They have multiple partners, with the females laying between 2 to 17 elliptical eggs. Elliptical eggs are elongated eggs with rounded edges. The baby snakes emerge after 28 to 29 days of incubation.

Parthenogenesis: Snake Reproduction Without the Mating Process 

rainbow boa
Photo by Bernard DUPONT on Wikimedia Commons licensed under CC BY-SA 2.0 (Cropped from original).

Parthenogenesis is an asexual form of reproduction among animals. The word parthenogenesis has its roots in the Greek language- parthenos means virgin, while genesis means origin.

In this form of reproduction, females reproduce without the influence of the males. The embryo forms with sperm fertilization, and the offspring doesn’t survive. There have been some cases of sexual reproduction in female snake species like boas, pythons, garter snakes, timber, and Aruba island rattlesnakes1.

Instances where Parthenogenesis occurred in snakes:

  • A 22-year-old Brazilian rainbow boa gave birth to four offspring in captivity after staying with a male snake that had a vasectomy. None of the young snakes had the DNA of the male that could have sired them.
  • A 10-year-old ball python born in captivity laid four eggs without mating with a male.
  • In 2020, the oldest ball python snake in the world laid seven eggs without mating with a male snake. This event happened at St. Louis Zoo. Two eggs didn't survive, while scientists took another set of two eggs for sampling purposes.

Conclusion: How Do Snakes Mate? 

In conclusion, the study of snake reproduction reveals wonders. Unique reproductive organs meet diverse courtship rituals. Across species, they birth through eggs or live young; some do not even undergo a mating process. The world of these serpents is more fascinating than we might expect.

1

Di Ianni, F., Albarella, S., Vetere, A., Torcello, M., Ablondi, M., Pugliano, M., Di Mauro, S., Parma, P., & Ciotola, F. (2023). Demonstration of Parthenogenetic Reproduction in a Pet Ball Python (Python regius) through Analysis of Early-Stage Embryos. Genes.

2

Folwell, M. J., Sanders, K. L., Brennan, P. L. R., & Crowe‐Riddell, J. M. (2022). The first evidence of hemiclitores in snakes. Proceedings of the Royal Society B: Biological Sciences.

3

Shine, R. (2003). Reproductive strategies in snakes. Proceedings of the Royal Society B: Biological Sciences.

By Jennifer Okafor, BSc.

Jen’s a passionate environmentalist and sustainability expert. With a science degree from Babcock University Jen loves applying her research skills to craft editorial that connects with our global changemaker and readership audiences centered around topics including zero waste, sustainability, climate change, and biodiversity.

Elsewhere Jen’s interests include the role that future technology and data have in helping us solve some of the planet’s biggest challenges.

Fact Checked By:
Isabela Sedano, BEng.

Photo by Sandaru Muthuwadige on Unsplash.
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