G-XF8B2QFYQ8
snakes that give live birth

List Of Snakes That Give Live Birth

Not all snakes lay eggs. Yes, it might sound a bit usual to most people. But there are plenty of snakes in the wild who give birth to live little baby snakes. Just like us. Snakes that give live birth are either viviparous or ovoviviparous. 

In viviparity, the fertilized egg or eggs are developed within the maternal body and take nutrition directly or indirectly from the mother. In this birth process, the newborns are already fully developed within the womb before birth. 

In the case of ovoviviparous snakes, the mother snake holds her eggs within her body until they hatch. So, the birth process seems like a live birth. 

Most of all snake species lay eggs (70%) besides a few snake species such as sea snakes, boas and vipers.. Here’s a list of some snakes that give live birth –

  • Anacondas
  • Rattlesnakes
  • Garter Snakes
  • Horned Sea Snake
  • Stoke’s Sea Snake
  • Grey’s Mud Snake
  • Yellow-Bellied Sea Snake 
  • Rough earth snakes
  • Boa Constrictors 
  • Pacific Ground Boa
  • Bevel Nosed Boa 
  • Bush Vipers
  • Albany Adder
  • Puff Adder
  • Two-striped night adder
  • Angolan night adder

Let’s take a more detailed look into the lives of these snakes.

Different Types of Live Bearing Snakes

There are different types of snakes that give live birth. These include sea snakes, boas, vipers and some others.

Sea Snakes 

sea snake

Sea snakes are a group of highly venomous snakes belonging to the subfamily Hydrophiinae. Most of them are completely adapted to sea life and rarely or never come ashore. Besides the Laticauda species (Sea kraits), all sea snakes give live birth (Ovoviviparous or Viviparous).

For example –

  • Horned Sea Snake
  • Stoke’s Sea Snake
  • Grey’s Mud Snake
  • Yellow-Bellied Sea Snake 

Boas 

Boas are medium to large non-venomous snakes. They are fairly primitive snakes. They can be found primarily in the Americas. But they are also found in Africa, Asia, Madagascar, Europe, and pacific islands. Most of them are ovoviviparous. 

For example – 

  • Boa Contractors
  • Pacific Ground Boa
  • Bevel Nosed Boa 

Vipers

live bearing snakes

Vipers are another group of highly venomous snakes. Long hinged fangs and highly toxic venom are some of their defining characteristics. They are found all over the world besides a few places like Australia, Antarctica, Hawaii, Madagascar, and other isolated islands. They are also mainly ovoviviparous.

For example –

  • Bush Vipers
  • Albany Adder
  • Puff Adder
  • Two-striped night adder
  • Angolan night adder
  • Common night adder

Others

There are plenty of other snakes scattered all over different families of snakes which give live birth. 

For example –

  • Garter Snakes
  • Rough Earth Snakes

Viviparous Snakes 

After fertilization, the embryo within the viviparous snake mother develops in a placenta. It directly receives nourishment from the mother. 

In viviparity, nutrients are directly transferred to the developing embryo from the mother through the placenta. In this case, there is no yolk. This sort of viviparity is more in common with humans.

After fully developed the baby snakes will break out of their mother’s uterus and wiggle out to take their first breath of fresh air. 

The newborn snakes are fully developed miniature snakes who can fend for themselves. So, the mother won’t be staying around to look after her litter. As cruel as it might sound, it’s a pretty common practice in the world of snakes. 

Besides the size, there isn’t much room for neurological or physiological development in the case of juvenile snakes. They know how to hide, hunt, and kill since birth. So, there is no need for nursing juvenile snakes into adulthood. 

Ovoviviparous Snakes 

Ovoviviparity is kind of like a bridge between egg-laying and live births. In this case, after fertilization, the snake mother develops complete eggs. This means the embryos are surrounded by yolk which is then surrounded by an eggshell.

But the eggs are never lain. Instead, they remain inside the mother’s body until they hatch. After hatching the newborns will wiggle out just like viviparous birth. The shells will remain inside the mother until completely absorbed. 

Snakes born in this manner are also fully developed since birth and are in no need of protection from their parents. So, the mother leaves as soon as she is done giving birth. 

Why Some Snakes Give Live Birth? 

At the beginning of snake history, there were only oviparous or egg-laying snakes. But in some cases, live-bearing provided a number of advantages that allowed some snakes to inherit viviparity or ovoviviparity. 

There is no one magical answer to why some snakes give birth. But there are some well researched and scientific guesses. 

First of all, herpetologists have noticed that most viviparous and ovoviviparous snakes are either large in size (Boas) or incredibly venomous (Vipers). In short, they all have a very strong defense mechanism whether it be their size or venom. 

This means these types of snakes don’t need to worry about being hunted by other animals. So, the decrease in mobility pregnant mothers face doesn’t affect these types of snakes that much. This allowed these snakes to develop the ability to give live birth. 

Giving live birth has many clear advantages over egg-laying. Egg-laying snakes have to make a nest. And some even protect it until the eggs are hatched. 

This imposes two problems. First, the eggs remain in a single spot and the snake has no way of carrying them to safety in case of predators or other dangers. 

Secondly, guarding the eggs or even just staying in the vicinity also puts the snake itself in danger of attracting predators.

But carrying the developing embryos or eggs is side her body until birth allows the snake mother to keep moving until she has to make a brief stop to give birth. This greatly ensures the safety of the mother snake and the success of birth.

Many of the live birth-giving snakes are found in rather cold climates. We all know eggs need a proper temperature to hatch. But snakes being ectothermic can’t produce their own heat. So, they can’t incubate their eggs as birds do. 

Live-bearing could be a method to do away with being at the mercy of nature for reproduction. The snake’s own body heat received from basking in the sun is enough to keep the eggs alive. 

This allowed snakes to venture into new territories with less competition and more food which gave them a clear evolutionary advantage.

Something similar happened to sea snakes. The waters had new territory to conquer, more food to eat. But laying eggs in water was not possible. 

This is because snake eggs are very porous which would allow water to easily seep in and ruin it. This probably pushed sea snakes to develop live-bearing. 

Live Bearing Vs Egg Laying 

When I said snakes evolved from being egg layers to livebearers it doesn’t mean that one is better than the other. Based on the habitat and living conditions of the snake both methods of reproduction have their uses. 

Let’s look into some of the advantages, disadvantages, and differences between these two methods of reproduction –

Mobility 

When it comes to mobility egg-laying has a clear advantage. Oviparous mother snakes don’t have to carry around the full weight of their offsprings with them constantly. Allowing them to be as mobile as they were before laying. 

Live bearing mother snakes have to carry around their babies with them until they are born. Making it quite difficult to move around. Especially, in the later stages of pregnancy. 

Safety

Egg laying is actually less safe for the snake and her eggs. Some snakes lay eggs in their nest and just abandon them. This leaves the eggs unprotected to predators. 

Some snakes do choose to guard their eggs until they have hatched (King Cobra). But that means staying in a single spot for weeks. This surely attracts predators which poses a greater threat to the mother snake. 

On the other hand, livebearers keep their eggs with them. This might slow them down but they are still able to stay on the move. 

Thus, making it difficult for predators to track them down. Also, livebearers are usually large in size or very venomous (Anacondas, Puff Adder). So, other animals generally stay clear of their way. This makes live-bearing safer than egg-laying. 

Number of Off-springs 

Because oviparous snakes don’t have to carry around fully developed baby snakes, they can produce more off-springs per pregnancy. 

Livebearers usually have a lower birth rate than oviparous snakes for the exact opposite reason. 

Protection from the environment

Protection from the environment means protection from heat, cold, rain, floods, droughts, etc. Snake eggs are very sensitive to environmental changes. 

Not having just the right temperature or humidity can cause eggs to be spoiled. Anything from droughts to floods can also completely ruin them. 

Viviparous and ovoviviparous snakes carry their embryos or eggs inside them. Thus, protecting them from harsh environmental changes. This ensures a greater level of reproductive success. 

Opportunity for territorial expansion

Obviously, live-bearing snakes take the cake on this one. Their developing off-springs are completely protected from the changes in the environment. Allowing them to expand into more adverse territories. 

For example, sea snakes spend most of their life in water. So, they developed live-bearing because eggs would be easily ruined if lain in water. Also, Rattlesnakes living in colder climates developed live-bearing as their eggs wouldn’t hatch in such low temperatures.

Evolution of live-bearing snakes

Learning about the process of evolution from egg-laying to live bearing can help us understand why there is so much reproductive and geographical diversity in the Serpentes suborder. 

There are many theories as to why this happened but none of that can actually be called a solid answer. All of these theories are based on educated guesses by researchers.

evolution of live bearing snakes

First, of all the Earth’s climate wasn’t always the same. We live in a world where everyone is panicking about global warming. 

Even though a rapidly warming climate by human influence is very real and alarming, that doesn’t change the fact that we are currently living in a relatively cold era in the Earth’s history.

A few thousand to million years back the atmosphere was much hotter than today. But slowly the Earth’s atmosphere cooled down due to all sorts of environmental changes. 

So, different parts of the world were cooling down to the point where it was getting harder and harder for snake eggs to hatch.

Snakes are very picky about when and where they lay their eggs. They’d rather hold on to their eggs and die from dystocia than lay their eggs in an unsuitable environment. 

With the gradual decrease in temperature snakes in different regions started to hold on to their eggs longer and longer. Eventually, they kept holding on to them until the eggs hatched, giving rise to ovoviviparity. This then further developed into viviparity or true live birth. 

Also, for sea snakes, the theory is a bit different. Their ancestors were probably forced to travel to the waters due to a shortage of resources on land. The sea being abundant with food they probably started spending more and more time in the water. 

But spending more time in water during pregnancy meant holding on to eggs longer as well. So, in time they also gave up egg-laying. Allowing many species of sea snakes to become fully aquatic. 

All of these geographical and habitual differences indicate the evolution from egg-laying to live bearing might have happened multiple times in the world of snakes. 

So, we can say that viviparity or ovoviviparity didn’t emerge only in a single species of snakes and later passed down to new generations. But it emerged multiple times in snakes of different species in different regions due to facing similar obstacles that required similar solutions.

This is a clear example of convergent evolution. According to this, animals from different parts of the world or even from different eras in time can evolve into having similar traits even if they are completely unrelated. 

Conclusion 

The world of snakes is filled with diversity. They are nature’s most adaptive creatures who have a history of going through drastic changes to ensure their survival. And that is what makes them so fascinating to me. 

Have any thoughts on snakes that give live birth? Feel free to share them with us and with the world in the comment section. Thanks for stopping by.

Reference Taken:

Wilfred T. NeillThe American Naturalist

Leave a Comment