Do snakes lay eggs? Well, of course they do. This is something we have known since our school days. But did you know that some species of snake give birth to live young ones, just like mammals do? I bet this is something you have not heard before or know very little about.
Members of the Elapidae and the Colubridae family of snakes, the two largest snake groups, lay eggs. Majority of snakes lay eggs to be honest. But there are certain venomous snakes and sea-snakes that prefer to give birth to live offspring. This choice in reproduction that snakes have been gifted by evolution certainly increases their chances of survival by ten folds.
Let’s tap deeper into this mystery and explore to know more!
- Do Snakes Lay Eggs
A Brief Introduction To Snakes
Whether you call them serpents, Slytherins, Kaa from Jungle Book, or Sir Hiss from Robin Hood, all fall in the wriggly, elongated class of reptiles in the animal world. Affectionately known as snakes, they fall in the order Squamata, and suborder Serpentes. At the first sight of them, certain individuals may go berserk, but little do they know, all snakes are not dangerous.
In fact, out of about 4000 species of snakes in the world, only about 600 are venomous, and 200 can actually subdue a human being as prey. These cold-blooded creatures are believed to have evolved from lizards, and some snakes, like the boa constrictors, actually possess vestigial legs as remnants of their ancestors.
Snakes can be found in every part of the world from northward Scandinavia all the way southward to Australia. However, snakes are totally absent from places like Antarctica and some islands such as New Zealand and Iceland. Owing to their superbly specialized skeletal structure, they can swallow down large prey like deer and antelopes whole.
Do Snakes Lay Eggs
People believe that all snakes lay eggs, but only about 70% of all the snake species in the world lay eggs. So how does the rest of the 30% bring their young ones to the world? They give birth to live offspring just like mammals do! This is mainly because babies within egg shells will not survive the harsh winter conditions in the colder regions or the northern parts of the world.
Examples Of Snakes That Give Birth
Snakes like the boa constrictors, vipers, rattlesnakes, green anacondas, and garter snakes, are a few names among others that give birth instead of laying eggs.
There are snakes like the taipans, tiger snakes, and death adders that are members of Hydrophiinae, a subfamily of venomous sea snakes, under the family of Elapidae. Except the Laticauda genus, for example the yellow-lipped sea-kraits or the Crocker’s sea-snakes, most other sea snake species give birth to live young ones. To further clarify, they do not lay eggs.
Sea snakes, like the yellow-bellied sea snakes, carry their snakelets for 6 months inside their belly before giving birth in shallow tidal pools. Copperhead snakes are another such example of unusual birthing. After copulation, they carry sperm inside their body until the conditions are more favorable. After successful fertilization, the eggs will form and hatch within the mother’s body, and then the snakelets will be given birth to, at a suitable time.
Examples Of Snakes That Lay Eggs
Most members of the Elapidae family, like pythons, cobras, adders, and mambas all lay eggs. Almost all members of the Colubridae family, including corn snakes, king snakes, and grass snakes, lay eggs.
The Reproductive System Of Snakes
Before we move on any further, let’s take a look at the reproductive organs and systems of a snake to know how these reptiles produce more of their own kind and keep the progeny alive.
The reproductive system of snakes is the collaboration of specific organs in a snake’s body that help it to produce eggs or young ones, and then lay the eggs or give birth to the fully-formed offspring. The reproductive system of a snake consists of various components. In females, we find the ovaries, oviduct, and the cloacal opening. In males, the organs that function for reproduction are the hemipenes and the testes.
The ovaries of females are elongated due to the natural, tubular shape of a serpentine body. These organs are located near the pancreas and gallbladder. In most species of snakes, there are two ovaries present, but in certain species there is only one ovary. The ovaries are fully equipped with epithelial and follicular cells, nerve and connective tissues.
The oviduct is the organ that is attached to the ovary and it transports the sperm cells from the male to the eggs of the female. They look like tubes and every ovary has two oviducts. This organ consists of a part called the “seminal receptacle” which stores sperm for a period of time to fertilize the eggs later. You will get a greater insight on this in the upcoming segments.
The hemipenes are the main male reproductive organ that is found in pairs inside pouches near the base of the tail. They are held in position by the retractor muscles.
Hemipenes are fork-shaped structures which are folded and stored inside the tail region of the reptiles. Each fold represents an individual male reproductive organ, and the snake chooses any one at a time to fertilize a female. The hemipenes could have hooks, grooves or spines on the surface so as to grasp at the cloacal opening of the females.
Each hemipene has one testis. Testes (plural) are cream-colored organs that produce sperm to fertilize female eggs after copulation. The testes in male snakes are elongated and are fully equipped with seminiferous tubules, connective tissues and blood vessels. Sperm is produced at the seminiferous tubules and ejected at the hemipenes.
The Cloacal Opening
Cloacal opening is present in both males and females. Males use them to expel feces and urine, whereas females, besides using them for defecation, use them during copulation, and laying eggs or giving birth.
Cloacal opening is present on the underside of the tail of both genders. It is hidden underneath a uniquely-shaped scale that is different from the scales present on the other parts of the serpent’s body. It opens only during usage so when it is closed it is almost invisible.
The Different Ways Snakes Reproduce
Not all snakes lay eggs, some give birth to live young ones. The methods at which baby snakes grow inside their mother and come to this world, can be broken down into three different categories. Let’s take a look at each one of them.
- Oviparous: 70% of all snakes in the world are oviparous. This is the process where eggs form inside the mother and when the mother is ready, she lays the eggs. After the eggs are laid, the mother may (or may not) incubate the eggs to keep them warm unless the babies come out of the eggs. Examples of oviparous snakes include corn snakes, king snakes, cobras and adders.
- Ovoviviparous: In this system, eggs form inside the female body and the babies even hatch inside the mother’s body. They are given birth to later, at a suitable time. This process is a mixture of egg laying and giving birth. Most rattlesnake species are an example of such snakes.
Snakes that live in cold and arid-desert climates are the ones who practice this process. They can continue carrying their babies inside of them unless the mother finds a suitable place to give birth in. In this way the babies, in their crucial stages of development, are protected from harsh environmental conditions.
- Viviparous: In this process, no eggs or egg shells are formed at all. After fertilization, embryos form and grow to live young offspring which are then given birth to, just like mammals do. This is very unusual in reptiles. Boa Constrictors and Green Anacondas practice this method.
How Do Snakes Copulate?
The reproduction season of snakes is generally in the spring or summer. In the Northern Hemisphere, the season starts in March and continues through May. In the Southern Hemisphere, the breeding season is usually between September and October.
When the breeding season approaches, and females are ready to mate, they release pheromones from the anal scent glands that are located near their cloacal opening. Pheromones attract as many males as possible.
If there is more than one male at the breeding ground, the males will wrestle and fight to mate with the single female, an event known as “combat dance”.
The hemipenes are used to penetrate the cloacal opening of the female and ejaculate the sperm there. The sperms then fertilize the eggs of the females.
Females could become impregnated immediately or they can store the sperms in their seminal receptacle for about 4 or 5 months (could be longer is certain species) and allow them to fertilize her eggs later. This is called delayed fertilization that takes place in ovoviviparous snakes.
How Do Embryos Develop Inside A Mother Snake?
At the beginning of the breeding season, the eggs in a female start storing yolk. After ovulation, the ovaries release eggs into the oviduct where fertilization will take place if male sperm are present. In oviparous or egg-laying snakes, the eggshells will form in the oviduct.
In ovoviviparous females, the embryo will develop in its fetal membrane within the oviduct. The embryo will receive nutrients from the yolk, and will receive water and oxygen via diffusion process through the oviduct.
How Do Snakes Lay Eggs Or Give Birth?
Just before the mother snake gives birth or lays eggs, she will display twitch-like movements, and breathe rapidly. She may also flick her tongue, and remain restless for 4 to 6 hours.
When she is ready to give birth or lay eggs, she will look for a warm and safe place. Decaying logs or leaf piles are good places in the wild.
By cloacal contractions and uterine muscle contractions, eggs or babies will slowly be expelled through the cloacal opening of the mother snake. When she lays eggs, her tail will lift up.
In case of egg-laying, eggs accumulate one by one into a pile. In case of birth, neonates are seen slowly gliding out of the opening, their mid parts first, because they remain folded within their mother’s womb.
In case of eggs laying, the eggs are either soft-shelled or hard-shelled. Soft-shelled or pliable eggs may lose or take up water like a sponge from the surrounding areas and thus gain or lose weight. Most species lay pliable eggs.
It may take 1 to 3 months for babies to hatch, depending on the species. All eggs hatch at around the same time with a maximum of two-day gap between each egg. The hatchlings have teeth to break through the shells.
The reproductive nature of snakes is truly miraculous. To know more about it, you may sift through the following frequently asked questions that we have arranged for you.
Q: How do snakes take care of their babies?
Ans: Brooding snake parents is a rare to impossible sight. Mother snakes of most species abandon their eggs right after laying them. Snakelets are fully on their own from day 1, and this is the reason why rattlesnake babies are fully equipped with venom and fangs immediately after they hatch from their eggs.
Some rattlesnakes, however, do stay around for sometime to prevent predation. The Eastern Rattlesnake babies stay with their mom until their first molt, while the Western Rattlesnakes scatter away from their mom hours or days after their birth.
However, there are certain species, like the King Cobra, that actually broods her young ones. It is believed that the male and the female mate for life, and even the males remain close by during nesting and brooding. The mother builds a nest for her eggs, incubates the eggs, and after the eggs have hatched, will stay with their snakelets for a while before leaving them.
Q: At what age do snakes start laying eggs?
Ans: Most snakes become sexually mature when they are 2 or 3 years old. In case they are small, malnourished or traumatized, they may take longer to reach sexual maturity. You can detect a sexually mature female by looking for her cloacal capsule near the ventral scale. In males sexual maturity can be understood by the appearance of scales near the anal region.
Q: What do snake eggs look like?
Ans: Snake eggs are not as rigid or hard as bird eggs. The shells are flexible, elongated or oblong in shape, and the outer layer has a protein cast coated with calcium carbonate crystals. Black Rat snakes, however, lay eggs that are almost as round as bird eggs.
Snake eggs are generally white, off-white, or beige in color, with or without blotches or spots. Eastern Racer snakes lay eggs with ridges that make the eggs look as if they have a sandpaper texture.
Q: What is egg binding in snakes?
Ans: Due to some abnormality in the reproductive system of the mother snake, eggs may bind or refuse to glide out of the cloacal opening. This is called egg-binding. It may also happen when females have failed to accommodate with the conditions of their current living place.
Gentle manipulation by an expert snake-breeder can help. The snake could also be bathed for 30 minutes to stimulate contraction. In severe cases, a surgery may be needed.
Snakes are known for their ferocious and adaptive nature. They can survive almost anywhere in this world except maybe some ice-covered islands. Their reproductive system is highly adaptive and specialized too– it is almost as if nature has customized their reproductive faculty to meet the varying needs of different snakes. Do snakes lay eggs? Well, eggs and much more!
About 70% of all snakes on this planet lay eggs, there is no doubt about that. But the rest give birth to fully-formed offspring that wriggle out of their mother’s belly after completing embryonic development. Some species, though rare, have even been found to reproduce asexually! Such a privilege will surely keep snakes at the top of the charts in the competitive natural world.