Venomous snakes are carrying a toxic substance in their bodies, so how can they avoid harming themselves? And how is it that they can eat prey and not be adversely affected by the toxins? What happens if a venomous snake bites itself?
Their venom glands don’t allow venom into their bloodstream, so it can’t hurt them. And when they eat prey with their venom in it, their stomach acid breaks down the proteins in the venom, rendering it harmless. However, snakes can still die from another snakes’ venom.
There is an exception to the rule. The kingsnake has become immune to other snakes’ venom too. Thousands of years of exposure has made them immune and is known to eat other snakes.
Are Snakes Immune to Venom?
Scientists can’t say for sure which snakes are immune. That’s because nobody has studied in depth the effects of snake venom on snakes.
The answer has the following implications:
- Why don’t snakes die when they eat animals they’ve just bitten with venom?
- Why don’t snakes die if they eat another snake, like the kingsnake?
- Can snakes accidentally bite themselves, and if they do, would they die?
- What happens if a venomous snake bites another venomous snake?
Some studies suggest that certain snakes are immune. Others say that they aren’t. But, confusingly, all snakes that have venom glands aren’t affected by them.
Can Snakes be Poisoned by Their Venom?
When a venomous snake bites its prey, the point—obviously—is so that they can eat it. So why doesn’t a snake die when they eat prey with venom in it? The answer is deceptively simple.
Snake venom is made up of proteins. Proteins are chemical compounds that the body needs to live and work, and to create things like hair, muscle and so on. They can also have adverse effects, destroying muscle or stopping the nervous system from working.
So that the body can get access to the proteins we need, we have to digest them. Stomach acid breaks them down into small chunks, so that they can be used for whatever we need them for.
When a snake eats prey with venom in it, the venom breaks down in their stomach and loses its effects. This applies whether a venomous snake is eating their prey, or a snake is eating a venomous snake, venom glands and all.
Of course, if the venom is injected in some other way, then the snake is still susceptible. However, many snakes do have a minor resistance to their venom—almost as if they were vaccinated.
Scientists aren’t exactly sure how it happens, but in some species, the natural antibodies in their blood can stop the venom before it does any damage. This isn’t always the case, and the snake can get hurt.
Can Snake Venom Kill Snakes?
Sufficiently potent venom can kill any vertebrate because of the way it works. There are many different kinds of venom, each of which attacks a different part of a vertebrate’s system. Since snakes are vertebrate just like their prey are, they can be hurt too. These are as follows:
- Neurotoxic venoms, which stop the nervous system from functioning, eventually causing paralysis and cardiac arrest.
- Myotoxic venoms, which causes muscle necrosis (very fast muscle death), again causing paralysis, and stopping the lungs from working.
- Cardiotoxins, which attach to the muscle cells in the heart. They stop the muscles from being able to contract, first causing irregular heartbeat, and then stopping the heart altogether.
- Hemotoxins, which seek out and destroy red blood cells or cause the blood to clot
- Phospholipases, which bind to fat and rupture cell membranes.
There are also different kinds of each venom, which is why we can’t just use one kind of antivenom for every snake bite. Different species of snake have different kinds of venom, made up of different proteins with different effects.
So, mambas, for example, have a kind of neurotoxin that paralyzes the nerves. King cobras have a neurotoxin that causes the same problems, but works differently. And mambas have cardiotoxins which attack the heart.
The point of all this is to say that of course snake venom can hurt snakes. Snakes have hearts, lungs, nervous systems and muscles too. They have everything we do. So, if they’re bitten and envenomated, then it stands to reason that they would be injured or die.
However, that’s not the entire answer, because some snakes are immune to certain venoms—and some snakes are a little immune to their own venom, too.
Can a Snake Die from Another Snake’s Venom?
The king cobra eats other snakes. It hunts common colubrids and other smaller snakes in southern Asia, its natural habitat. It will hunt them just like it hunts any other animal.
It will sneak up on it, before launching at the other snake, striking it and envenomating it. While the other snake becomes paralyzed, the king cobra will eat it whole.
However, some snakes have developed immunities to particular kinds of venom. The common kingsnake, for example, earns its name because it eats other snakes. Because it shares a range with the rattlesnake, it comes across them often, and has developed an immunity to their venom.
It all depends on how well a certain species has adapted to its neighbors. Some snakes will have been sharing a habitat with their venomous cousins for millions of years, whereas others won’t.
And some snakes will have developed a mutation that gives them immunity, while other species haven’t. At the same time, the venomous snake is trying to develop newer, stronger venoms too, so it’s like they’re trying to outcompete each other. It’s evolution in action.
Are Pythons Immune to Venom?
Pythons are constrictor snakes, so they don’t have venom glands. But they do share ecological ranges, across the globe, with snakes that do.
The reticulated python is an example. It lives in southeast Asia—but so does the king cobra, which loves to eat other snakes. So, is the reticulated python immune to venom?
No, they aren’t. King cobras only very rarely attack snakes as large as a reticulated python, merely because they would be challenging to eat. However, when they do come across each other, each snake can kill the other.
The king cobra can use its venom to paralyze the reticulated python slowly. But in the meantime, the reticulated python can use their incredibly strong death-grip to squeeze the life out of the king cobra.
Other pythons can be killed with venom, too, including ball pythons. Ball pythons in Africa, though, don’t have any kingsnake species to contend with.
They don’t have any snake-eating species in their range. The Mozambique spitting cobra does live in Africa, but further south, and prefers to eat black mambas instead!
Will a Snake Die If It Bites Itself?
They can, and there was an excellent example of just that in the journal Toxicon. A brown tree snake, which is venomous but not deadly to humans, was found that had clear signs of self-envenomation.
The authors found that the snake started to twitch and have difficulty moving twenty minutes after the bite, and was partially paralyzed at six hours.
Respiratory arrest and cardiac arrest followed 12 hours after envenomation. These are classic signs of the brown tree snake’s venom.
However, snakes can’t die from having venom in their own venom glands. Here, the venom is stored safely, where it can’t hurt the snake. Otherwise, the whole system would be pointless.
There’s something similar that we have—our pancreas. If our pancreas were to burst, which can happen, the enzymes start to break down your organs. Both snake venom and these enzymes have detrimental effects by getting into an animal’s bloodstream.
From there, the venom can spread all around the body, affecting:
- Nerves and nerve endings
- The heart and lungs
- The tissue surrounding the bite wound
But to have these effects, it must get into your bloodstream. Spitting cobras can fire venom at you, for example, as a defense mechanism. However, the point isn’t to try and kill you, but scare you off.
If you’re splashed with venom, it can cause a stinging and painful rash. However, this won’t have the same effects as being bitten.
Snakes aren’t affected by their own venom because it’s stored safely in their venom glands, where it can’t get into their bloodstream. But what about the venom that they use to kill their prey? Won’t that kill them once they eat it?
Will a Rattlesnake Bite Itself If Cornered?
Rattlesnakes—in fact, all snakes—can sometimes bite themselves. They don’t do it because of some strange evolutionary mechanism, or because they’re stupid. It’s a case of getting confused, or not being in full control of themselves.
There are many reasons why they might bite themselves, including:
- Snakes strike quickly, in just a fraction of a second. In a high-stress situation, it’s possible for the snake to accidentally bite their own tail when they’re trying to strike at you.
- Snakes don’t have good eyesight. They lack a fovea, which is a very small pit at the back of an eye. This tiny pit helps the eye focus on minute details, like the words that you’re reading now. Since snakes don’t have a fovea, their vision is much blurrier. They rely on smell and movement to hunt rather than detailed vision, so if they saw their tail moving when they were trying to strike you, they could get confused.
- Their vision can get even worse when they’re shedding. They form an eye cap underneath their existing eye cap, so their eyesight is diminished before they get the chance to shed their old skin. Again, this makes it more likely for them to bite themselves.
Besides all that, a snake’s biting instinct is very strong. It’s a reflex, just like how we reflexively catch something that’s thrown at us. This reflex is so strong that even decapitated snakes can still bite. When you’re dealing with reflexes, it doesn’t matter how smart an animal is—accidents can happen.
Animals Immune to Snake Venom
Some animals have become immune to snake venom over thousands of years. The snakes continue to evolve more potent and deadly venoms, but their prey evolves resistance so that they can avoid death by snake bite. The mongoose is an excellent example.
According to the Proceedings of the National Academy of Sciences, the mongoose has special nerve ending receptors that are immune to cobra venom. Plus, they’ve also evolved long, shaggy coats that are difficult for cobras to bite. Plenty of other mice and rats have developed similar resistances, too.