Snakes are classified as reptiles and thus display some common traits we’ve come to expect from this class of animals. One of them is their reproduction.
Most snakes lay eggs that hatch into fully-independent snakelets. But this doesn’t apply to all snakes.
We’re just scratching the tip of the iceberg here. In actuality, snake reproduction is quite diverse, complex, and even mind-blowing!
For example, did you know there are different types of egg-laying snakes or that some snakes don’t lay eggs at all? If not, keep reading to discover more fascinating facts on this topic.
Types of Egg-Laying Snakes
The vast majority of snakes lay eggs. They do so in clutches, which vary in the number of eggs from one species to another. As is the case with most reptiles, snakes abandon their eggs almost immediately after laying them.
This applies to nearly all egg-laying snakes, such as:
- King snakes
- Mud snakes
- Corn snakes
- Parrot snakes
- Kraits
- Etc.
Although they’re extremely rare, brooding egg-laying snakes also exist. These snakes look after the eggs, which is atypical for most reptile species. For instance, brooding snakes coil themselves around the eggs to keep the growing baby snakes warm.
Biologists have documented this behavior in cobras and various python species, including blood and banded rock pythons.
What’s unique about brooding snakes is that they can generate body heat to keep the eggs warm, even when temperatures drop below optimal levels. You read that right— a cold-blooded snake can generate body heat!
Mother snakes do so through muscle contractions. This increases the snake’s metabolism and, thus, its body temperature.
Egg-Laying versus Live-Bearing Snakes
Despite classifying as reptiles, snakes as a group are very diverse in their breeding strategies. Some lay eggs, which you’d expect from reptiles.
But others give birth to living young, and some are somewhere in-between these two categories. Pretty confusing, right?
Well, it doesn’t have to be! We can make sense of this mess by separating snakes into different sub-groups, depending on how they reproduce.
Let’s start with the egg-laying snakes, which can be either:
Oviparous
Oviparity means that the snake lays eggs. Fertilized snake eggs contain a live, growing embryo that keeps developing once the eggs are out of the mother snake’s body. When the baby snake is done developing, the eggs are ready to hatch.
Oviparous snakes can lay just 1-2 eggs, or up to 100 eggs per clutch, depending on the snake’s species. Thanks to this, oviparous snakes are highly prolific.
Oviparous snakes typically don’t look after their eggs or young, either. When hatching, baby snakes from oviparous species are entirely independent.
Oviparity is the most common type of reproduction in reptiles, snakes included. It’s estimated up to 70% of snake species fall within this category. Some examples of such snakes include cobras, pythons, rat snakes, grass snakes, and king snakes.
Ovoviviparous
Ovoviviparous snakes don’t fit into a neat category. They don’t give birth, but they don’t lay eggs either. Instead, they produce eggs with growing embryos but keep them inside their bodies as the babies develop.
Then, when the babies hatch, the mother snake releases the live young from her body. This is often mistaken for a live birth, but as you’ll see later, the two reproduction methods are different.
Scientists believe that ovoviviparity evolved in snakes living in colder climates to ensure reproductive success. Ovoviviparous snakes carry their eggs inside the body to shield the growing embryo from hostile conditions like low temperatures. Examples of ovoviviparous snakes include some pit vipers and garter snakes.
But how does this work, you ask? Instead of releasing eggs after fertilization, these snakes keep them in their oviducts. The oviduct is a canal that connects the ovaries to the cloaca in female snakes.
Unlike egg-laying snakes, ovoviviparous snakes produce eggs with a very thin outer membrane. The eggs are highly permeable and allow the mother to pass oxygen to the eggs. However, the embryo gets all of its remaining nutrition from the yolk sack in the egg.
Then, there are live-bearing snakes, also known as “viviparous” snakes.
Viviparous
Viviparous snakes are the rarest. Although they’re reptiles, they experience what we’d consider a true pregnancy. They also give birth in the true sense of the word. Once the snake’s reproductive cells are fertilized, they implant into the snake’s womb, where they start growing into embryos and then baby snakes.
There are no eggs involved. The developing snakes sit snugly in the mother’s womb, receiving nutrients through the snake’s placenta. Once the baby snakes complete their development, the mother gives birth through her cloaca.
At first glance, ovoviviparous and viviparous reproduction look very similar. But again, live-bearing snakes don’t carry any eggs. Viviparity is thought to have evolved in previously oviparous species.
This could be an adaptation to harsh environmental conditions, where eggs would be vulnerable to shifts in temperature and humidity.
Viviparous snakes can produce litters of 2-150 snakes, depending on the species. The young snakes of live-bearing species are generally smaller than those of egg-laying species.
Examples of viviparous snakes include green anacondas, boa constrictors, and water snakes.
What Are Snake Eggs Like?
Snake eggs vary slightly in size, depending on the species. Smaller snakes produce eggs that are about 1 inch long.
In larger species, the eggs might reach up to 3-4 inches. Apart from size, the eggs of different oviparous snakes have much in common.
Starting with shell color, snake eggs have a very pale, off-white tint. As for the shape, they’re not rounded like other eggs you might’ve seen. Instead, snake eggs are narrow and elongated like a capsule.
The shell is thin and leathery to the touch. Since reptiles are highly sensitive to humidity levels, the egg’s membrane must be permeable enough to allow the outside moisture to pass through.
But because of this, the eggs are also quite soft and delicate. Although the eggs normally have a uniform and smooth shell, sometimes they can become dented due to mechanical pressure.
Where Do Snakes Lay Their Eggs?
Snakes don’t incubate their eggs, but they still need to provide the embryos with a warm and humid environment. Thus, mother snakes seek hidden spots with optimal temperature and humidity.
Typical spots include mounds, burrows covered with loose soil or compost, underneath bushes, inside tree stumps, under logs, and sometimes even in animal manure!
Any spot is suitable as long as the temperature and humidity are between 78- 84°F and 75-85%, respectively.
The hiding spot should also be safe from predators and other environmental dangers.
How Many Eggs do Snakes Lay?
Snakes lay eggs in clutches, but the total number of eggs per clutch is variable. As a whole, snakes can lay one to over 100 eggs at a time! But separate species have narrower ranges of eggs per clutch.
Smaller snake species produce less, while larger snakes are more prolific. For example, corn snakes typically lay 10-30 eggs. Smooth green snakes lay just 4-6 eggs per clutch. In comparison, some pythons can lay 100 eggs or more.
Note that not all eggs are going to be viable. Although snakes can lay dozens of eggs, not all of them will hatch.
Eggs that aren’t an off-white color are usually not viable. Sometimes, hatchlings will die during hatching or shortly after.
Incubation Processes for Snake Eggs
Incubation is the period that lasts between egg laying and hatching. During this time, the embryo inside the egg matures into a fetus and later becomes a baby snake.
This is the most delicate period in a baby snake’s development, as the eggs are defenseless and at the mercy of environmental factors.
During incubation, the embryos get nutrients from the yolk inside the egg. As they develop into fetuses, the yolk part gets more depleted and deflated, making room for the growing baby snake.
Besides the yolk, the snake embryo is surrounded by other membranes, including:
- The amnion (keeps the embryo and the amniotic fluid, a watery substance)
- The allantois (a fluid-filled sack with tiny blood vessels; it collects waste and allows the exchange of gases for the growing embryo)
- The chorion (a membrane that separates the fetus from the albumen, a moisture and protein-rich membrane)
When the embryo reaches the fetus stage, the allantois and the chorion fuse together. Eventually, the nutrients run out, and the baby snake is fully developed and ready to hatch.
– Factors Affecting the Incubation Process
Successful incubation depends on key environmental factors, namely temperature and humidity levels.
Snake eggs need both warmth and moisture to thrive. Inappropriate temperature and humidity levels almost invariably kill the eggs.
The ideal incubation temperature for most snake eggs is 78- 84°F, while the humidity should be 75-85%. Under low temperatures, embryo development stops completely.
Extreme temperatures, on the other hand, can potentially cook the baby snakes in the shell! Low humidity can shrink the eggs and cause irregular shell shape and texture.
As a note, incubation temperature influences not only the hatching rate but also the behavior of hatchlings. Scientists have observed that hatchlings developed under lower temperatures were slower and less apt to fend for themselves.
Unlike in other reptiles, incubation temperature doesn’t affect the sex of snake hatchlings. The sex of most snakes is determined at fertilization.
– How Long Does Incubation Take?
The length of the incubation period varies depending on the snake species and environmental temperature.
The common range for most species is 50-70 days, with 57 being the average time in optimal conditions.
Lower temperatures will lengthen the developmental period and might lead to smaller snakes. Higher temperatures speed up development but might also kill the sensitive eggs.
For the highest hatching rate and optimal times, the eggs should incubate in low 80s temperatures.
– Hatchling Development
Hatchlings first emerge with a single small tooth on their upper lip. They use this to crack open the shell. Once hatched, the baby snakes are fully independent and capable of feeding themselves.
However, during this life stage, they rely more on taste and other senses; their eyes aren’t fully adapted yet.
Shortly after hatching, the baby snakes shed their skin for the first time. The egg tooth also drops during this first molt. Throughout the first 2-4 years of its life, the hatchling develops into a snakelet and then a sub-adult.
Smaller snake species reach maturity at two years, while larger snakes typically become adults at four years or more.
As the snake feeds and grows, it will molt up to 12-16 times a year. The growth rate is most rapid during the first year of life.
As the growth slows and the young snake reaches early adulthood, the shedding rate drops to 4-8 times a year.
Predators of Snake Eggs
Snake eggs aren’t just vulnerable to the elements. Predators represent another major threat. This is true, especially because snakes don’t look after their eggs. Since they’re left unattended for the entire duration of their development, snake eggs are defenseless against natural predators.
The list of potential threats is quite long and includes the following:
- Hawks
- Owls
- Skunks
- Raccoons
- Foxes
- Honey badgers
- Bobcats
- Snapping turtles
- Falcons
- Mongooses
- Other snakes
Of course, the predators of snakes depend on the snake species and its environment. As for snakes preying on other snakes, this happens between different species when there’s a large size difference.
Such an example would be the kingsnake, which preys on smaller species. Even after hatching, the young snakes are still vulnerable to natural predators.
Conclusion
Most reptiles, snakes included, lay eggs. This is true for 70% of all documented serpent species. These snakes lay clutches of 1-100+ eggs and typically abandon them in a warm, hidden spot.
Pythons and cobras are among the few egg-laying snakes that brood their eggs throughout the incubation period.
Other types of snakes are even more unique. Ovoviviparous snakes incubate and hatch the eggs inside their bodies.
Viviparous snakes don’t produce eggs at all but carry the snake embryos in the womb and give birth to living young.
