All animals need to reproduce to keep their genus alive. While snakes may spend a lot of their time hunting and feeding, this is all done so that they can find a mate, reproduce, and pass their genes on to the next generation.
Males know that the female is ready due to a scent trail left by her. The male will rub his chin on the back of the female and, if receptive, will climb up the body. He will inject his sperm to fertilise her egg using a pair of penises called hemipenes. They may stay together for a few minutes or hours before disengaging.
Snake reproduction is fascinating, so please read on if you want to know more.
Breeding cycle of snakes
The breeding cycle depends on where in the world they live. Snakes will typically mate every year or every two years in temperate areas. Mating occurs in spring or early summer, with the eggs or young produced by the end of the hot season. They will then replace their food before hibernating in autumn.
During hibernation, the sperm and the eggs develop, allowing them to breed the following year. However, species with only a short season to reproduce may require another year to recover.
These are general timelines for reproduction in snakes, although some species will mate as soon as emerging from hibernation, and others will mate before hibernation.
Longer days in spring initiate the mating season for most snake species. Although the rising temperatures indicate that spring has come, hot days in winter also occur, so these are not always reliable. Snakes will look to breed with the longer days and minimum temperatures occurring for a few days in a row.
Snakes can sometimes produce young eggs without mating that season, with the female storing the sperm from the previous season before hibernation.
Like those in temperate areas, snakes in tropical areas do breed seasonally. However, without the increased temperatures that spring brings in temperate regions, they have to rely on other indicators that it is the breeding season.
More prey, less humidity and rainfall bring on the breeding season for snakes in the tropics. While some may breed throughout the year, most will breed after hibernation. Most tropical snakes will only reproduce once a year, even if they do not hibernate for as long as other species.
The breeding season lasts for about six weeks. Although they will not usually breed immediately after hibernation, they soon turn to courtship and mating.
Males will contest with each other to find a mate, either by pushing others away or posing and hissing at each other.
How do snakes mate?
Snakes are generally solo animals, but this all changes when the mating season arrives. Male snakes can become much more aggressive at this time.
As with many other animals, males are attracted to females by a scent trail left by a female. The scent shows that they are ready to reproduce and is produced from the anal gland and the skin. The female will brush against vegetation and will sit with the anus open.
Males will judge the female’s receptiveness by flicking their tongues on their bodies to assess the scent. These body oils play a part in males knowing when females are in heat. Pheromones play a huge role in snakes’ mating and courtship.
When the couple meets, the male will rub his chin on the lower back of the female. The female often jerks her body, and as long as she is perceptive, the male will crawl forward. At this point, the female may race ahead but will soon give up.
As he presses his body against her entire length, the tongue flicks continue. He vibrates the rear of his body against hers and tries to bring his tail under her. She will lift her tail and open her cloaca if she is receptive.
As the genitals get closer, they twist their tails together, and the male inserts one of his two hemipenes. He will then fertilise the eggs inside the female. The hemipenes are effectively two penises that usually are inverted and resting in a cavity at the base of the tail.
The hemipenes are turned inside out on erection and withdrawal and consist of tissue tubes. Some species have spines on to assist with grip, such as boas and pythons. The spines are parts of the pelvic limbs and can grip the female, as can the jaws.
The male gives a few jerks of their body and taps his against the female’s body.
The couple may stay joined for a few minutes or hours, sometimes up to one day. Males are usually smaller and can be dragged around at this time. The male will generally go his way afterwards, although some species stay together until egg-laying occurs.
Because most males do not protect their females after mating, some species use a copulation plug. This waxy material is put into the female cloaca after mating before falling out a few days later. It is thought that this is to stop others from mating with her.
After mating, the testes grow in preparation for the breeding season next year.
Can some snakes have young without mating?
Interesting, some snakes do not need to mate with another snake to have offspring, and the young are produced from unfertilised eggs. This is called parthenogenesis and can be found in whiptail lizards, spectacled lizards, and some geckos. The largest reptile to reproduce without a mate is the komodo dragon.
There is more evidence that there are more snakes that use parthenogenesis. Asexual snakes include the Brahminy blind snake, a small, burrowing species found in Africa and Asia. Studies of the Burmese Python in 2003 also showed that they could give birth without mating.
A Burmese python was given to Artis Zoo in Amsterdam in 1995 and was still producing clutches of eggs in 2002. Copperheads and cottonmouths, both members of the pit viper family, have been studied and are known to reproduce asexually.
Do snakes lay eggs or give birth to live young?
Snakes are known for laying eggs that hatch their young. However, this is not true for all species of snake. Some snakes produce eggs that they don’t lay and are kept inside the body. The rattlesnake, for example, produces eggs that are hatched inside the body three months before their actual birth.
These snakes are called ovoviviparous, and their birth is different to most other animals that give birth to live young. Ovoviviparous young are developed in the body and kept there to continue their development.
Snakes born in this way feed on the yolk from their egg sac when hatched inside the adult, and they do not have the adult placenta to feed on or get oxygen.
Snakes born in this way are more developed than others, which can be seen in their larger size and their independence. Some ovoviviparous snakes include adders, copperheads, flying snakes, cobras, kingsnakes, and pythons.