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Can animals be immune to venom?
Before we begin, it’s important to understand the difference between immunity and resistance. Many of the following animals have venom resistance, meaning they have developed some way to combat snake venom through their evolutionary history, but it isn’t always perfect. A venom resistance gives potential prey an advantage if they are tagged by a venomous snake, but they probably don’t want to make a habit out of it! Immunity, on the other hand, is the complete ability to nullify the effects of a snake’s venom. Each of the animals below will have some level of resistance to snake venom but may not be totally immune. Additionally, we are going to cover resistances to rattlesnake venom specifically, although there is often overlap when it comes to the venom of other snakes. As a result, all of these animals will live in North America since that is where rattlesnakes live! These adaptations are truly remarkable, and a few of the contenders on the list are likely to surprise you!
A list of the animals immune to rattlesnake venom
Woodrats
One of the most surprising animals on the list is the woodrat. Woodrats are commonly known as packrats due to their habit of collecting things in their dens and burrows. The discovery that woodrats had a natural immunity to rattlesnake venom was completely an accident and occurred during a science experiment in a classroom! In 1976, a student at Texas A&M University was asked to feed one of the snakes that belonged to the research center at the school. Grabbing a rodent, the student gave the western diamondback in their care a woodrat, thinking his job was done. Watching, the rattler struck, and the fight was over… but it wasn’t. The mouse was incredibly unaffected. When the student saw what had happened, further research was conducted, and the shocking discovery was revealed!
Kingsnakes
You don’t get to slither around with the name “kingsnake” if you aren’t the true king of snakes. Thankfully, kingsnakes come by their title honestly. They actually get their name from their habit of preying on other snakes as their primary source of food. Kingsnakes regularly prey on the most venomous species of snakes in the US, including copperheads, rattlesnakes, and cottonmouths. There are various species of kingsnake across the United States, and all of them love to snack on rattlesnakes like they are gummy worms! Incredibly, kingsnakes aren’t even venomous themselves, preferring to constrict their food. Kingsnakes have the strongest relative constriction of any snake in the world. The resistance of kingsnakes comes from a special enzyme that inhibits the binding of pit viper venom, rendering it mostly ineffective. Although they aren’t totally “immune,” they are strongly resistant.
Indigo snakes
The eastern indigo snake is another snake that has developed an immunity to all North American rattlesnakes. Since the eastern indigo snake occupies the same locations as many rattlesnake species, and they are immune to their toxic venom, the eastern indigo snake is a dangerous predator to rattlesnakes, feeding on them at will. Indigo snakes are themselves nonvenomous and similar in size to the eastern diamondback rattlesnake. They are truly beautiful snakes, although they are currently threatened across much of their range in the southeastern United States. They can currently be found in Georgia, Alabama, Mississippi, and South Florida. They like to dwell in longleaf pine forests, which have been reduced to less than 5% of their original historic size. At one point in the mid 1950’s, indigo snakes became completely extinct in Alabama, but were reintroduced by animal researchers in the 80’s. They’ve also been caught in large numbers for the pet trade, which has reduced their numbers in the wild.
California ground squirrel
Another surprising member on our list, the California ground squirrel seems to be the most unlikely animal to be resistant to rattlesnake venom! Ground squirrels are some of the rattlesnake’s most common foods, making the resistance even more surprising in some ways. There are many species of ground squirrel, and not all of them are immune. The California ground squirrel has a unique resistance to rattlesnake venom that is directly associated with the presence of rattlesnakes in their environment. Another adaptation these squirrels use to defend against rattlesnakes is truly remarkable. When they encounter the shed skin of a snake, they will chew it up and spread it across their bodies to mimic the smell. Since snakes hunt by smell, these squirrels effectively camouflage themselves with the skin of their top predator.
Opossums
Opossums (commonly referred to as possums) live across most of the United States and are some of the oldest mammals around. They have developed a natural immunity to resist pit viper venom, of which the rattlesnake is included. In fact, they are so good at producing a special peptide that completely neutralizes the venom that studies are currently being done on them to discover potential uses.
Pigs
Although they are generally regarded as silly, sloppy creatures, pigs are incredibly hardy animals descended from the wild boar. Wild boar spend their lives foraging for food in the places that snakes love to hang out, so it makes sense that they would have developed a natural immunity to some of their venom. There is a common belief that pig fat helps to reduce the damage done by snakes, but research has shown that their fat doesn’t do much since the venom can easily travel through it. Still, there is another mechanism that gives them their resistance. Their resistance is to the a-neurotoxin in snake venom, specifically. Domestic pigs have a genetic mutation in their cell receptors that prevents binding of the a-neurotoxin, rendering the venom useless. The resistance doesn’t occur in most pigs until they are adults, so small pigs are still vulnerable. This is likely the reason that pigs are known to actively attack snakes that are near their enclosure. It’s a behavioral defense response to their piglets not being immune quite yet.
Animals that could be immune to rattlesnake venom
Since rattlesnakes only live in the Americas, the primary creatures that are immune to them live there as well. Still, there are some animals that could be immune if they happened to run into one of these scary snakes.
Hedgehog
These cute little animals live in Africa and are known for their little spines and habit of curling up as a defense. Their spines act as a physical defense, but they also have a hidden defense found within their bodies. These adaptations are important for these little creatures since they make a habit of eating other snakes, especially venomous ones! Although they aren’t totally immune, the added resistance can help if they accidentally get tagged by a fang.
Honey badger
One of the more famous examples of a venom-resistant animal is the honey badger. These creatures are famed for their incredible toughness and the ability to steal honey from hives without any ill effects. There are two things that help keep them safe from dangerous snakes: their skin and their genes. Honey badgers have incredibly tough skin that is known to deflect human machete chops. If a snake can’t get its fangs into you, it can’t get the venom in either! Additionally, honey badgers have developed a natural immunity to Elapidae venom.
Mongoose
The mongoose is probably the most famous of all the venom-resistant animals on our list. They aren’t totally immune, but they are well-known as hunters of even the deadliest of snakes. Their speed and venom resistance combine to make them one of the best snake hunters around.
Summary of 6 Animals Immune to Rattlesnake Venom
Let’s recap the animals known to be immune to rattlesnake venom:
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