People and Snakes

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Throughout history, many people have feared snakes. A recent study is trying to determine whether the fear of snakes is something people are born with or whether they must learn it. This grass snake is nonvenomous. It is harmless to humans, feeding mostly on amphibians.

Ophidiophobia is the abnormal fear of snakes. Ophidio- comes from the Ancient Greek word ophis, meaning snake. A phobia is when someone has an extreme, strong fear of something—especially when the fear is irrational.

Like any phobia, ophidiophobia, is not a simple dislike or even some unease. About 50 percent of people get anxious around snakes. This is still not a phobia. For the 2-3 percent of people who have ophidiophobia, symptoms are not limited to minor anxiety. They might start screaming or crying when shown only a picture of a snake. They might avoid hiking or camping because they worry they might encounter snakes in the woods. In extreme cases, symptoms can include dizziness, fainting, and chest pain.

Since many people are afraid of snakes, psychologists wonder if humans have an innate fear of them. They wonder if people are simply born disliking snakes, or are they taught to fear them?

Legendary Snakes

Genesis is the first book of both the Jewish and the Christian Bibles. The book includes the story of the first humans, Adam and Eve. God instructs that they are not to eat any fruit from the Tree of the Knowledge of Good and Evil. However, they were tempted to eat the forbidden fruit by a wily serpent. Snakes, the book describes, are the most “cunning” land animals. God punishes Adam, Eve, and the serpent for disobeying. As part of the snake’s punishment, God creates a perpetual dislike between humans and snakes. According to the story, humans will seek to harm snakes while snakes will  harm humans in return.

The ancient fear of snakes is not limited to the Bible. The Pima people of North America have a legend about how snakes brought death into the world. According to the legend, after people and animals were created, they lived together peacefully. One of the animals was Rattlesnake. Because it moved so gently, it was nicknamed Soft Child. Everyone liked the sound whenever Soft Child rattled its tail. They liked it so much that they constantly poked and scratched at Soft Child, hoping to encourage it to rattle.

Rattlesnake soon grew tired of always being bothered. It went to Elder Brother for advice. In response, Elder Brother created fangs for the snake. Elder Brother suggested that whenever anyone bothered Rattlesnake, it should bite.

That evening, Rabbit visited the snake hoping to hear its pleasant rattling. When Rabbit scratched him, Rattlesnake unexpectedly bit Rabbit. Rabbit scratched at the snake several more times but was bitten each time. After so many snake bites, Rabbit became very sick and died. The legend said that Rattlesnake was responsible for the very first killing in the newly-created world.

Natural or Learned?

In 2017, researchers from Germany and Sweden wanted to see if people were naturally afraid of snakes as well as another creature many people are scared of, spiders.

The test subjects included 48 6-month-old babies. Researchers had the babies sit on their parents’ laps. The babies were then shown images of snakes, spiders, flowers, and fish. To ensure that the parents’ reactions did not influence their children’s responses, each parent wore dark glasses that made it impossible for them to see the images.

The same part of the brain that processes stress is also associated with whether a person’s pupils get smaller or larger. Because of this connection, scientists sometimes measure a subject’s pupils to determine whether something is making them anxious. When the babies saw pictures of flowers or fish, the size of their pupils did not change. However, the pupils in their eyes got larger when they were shown pictures of snakes or spiders.

Because the babies’ pupils became larger when shown pictures of snakes, lead researcher Stefanie Hoehl concluded the babies’ reactions were innate, not taught. “There was a definite stress response in the brain,” Hoehl said. However, Hoehl cautioned that dilated pupils are evidence of intense focus but not necessarily fear. Hoehl thinks that this highly-focused state is an inborn defense mechanism protecting humans from snake bites.

“It’s a very long period of coevolution—nearly 40 to 60 million years of it, that early human ancestors and spiders and snakes have interacted,” Hoehl said. Human ancestors who feared of snakes were less likely to receive deadly snake bites. According to this point of view, the fear was then passed genetically to their offspring.

David Rakison of Carnegie Mellon University researches early infant development. He does not agree with the team’s findings. “The current work, and indeed no existing work, has provided evidence that fear of snakes or spiders is innate,” Rakison says. The babies’ fear only seems innate because this fear is learned very early in infancy. “Infants possess a specialized fear mechanism that means that they are ‘prepared’ to learn quickly that snakes and spiders are associated with a specific emotional or behavioral response,” he explains.

Dogs and Snakes

Researchers do not all agree whether the human fear of snakes is innate or not. However, one fact seems beyond debate: dogs are not afraid of snakes.

A recent study found that dogs can smell the difference between venomous and nonvenomous snakes. However, instead of finding the smell of venomous snakes frightening, dogs find the smell interesting. Dogs are therefore more likely to sniff a poisonous snake than avoid one. Also, veterinarians say that when dogs are bitten by rattlesnakes, they are usually bitten on the face or neck. The location of the bites suggests that the dogs bitten were actively investigating the snakes and not avoiding them.

Researchers presented bits of scented newspaper to 171 dogs. Some of the paper was coated with the scents of animals harmless to dogs like mice, snails, and a nonvenomous rosy-boa snake. Some papers were covered with the scent of of the venomous Pacific rattlesnake. By seeing how each dog sniffed the newspapers, researchers determined whether each dog was fearful or not.

Scientists know that dogs use one of their two nostrils to smell in different situations. If they saw which nostril each dog used to smell the newspaper, they could tell if each dog was afraid or not. Since none of the dogs seemed to favor one nostril over the other when sniffing the rattlesnake-scented newspaper, researchers concluded that the dogs were curious but not afraid. Surprisingly, even though some of the dogs tested had been bitten by rattlesnakes in the past, that fact seemed to have no influence on their reaction to the rattlesnake-scented newspaper.

It is possible that dogs are not afraid of snakes because dogs evolved separate from them? The authors of the study say no.Canids evolved in the presence of constricting and venomous snakes,” researchers said, “and their olfactory systems are extremely sensitive, making odors particularly well-suited to mediate threat detection.” This led researchers to conclude that dogs never considered the snakes to be a big enough danger to them. If they had, dogs would have likely evolved an innate fear of snakes.

This harmless northern water snake is frequently mistaken for the venomous cottonmouth snake, commonly called a water moccasin. In many U.S. states, it is illegal to kill any snake unless it poses a real threat to humans or livestock. Experts say that most confrontations with snakes can be avoided by simply leaving a snake alone.

Snakes and Pets

Studies show that both dogs and cats in the United States receive about 150,000 poisonous snake bites each year. While bites are painful to both humans and pets, the bites are actually far more dangerous to dogs and cats. About 30 percent of dogs and cats bitten by snakes die from the venom. In comparison, less then 1 percent of humans bitten die from snake bites. In fact, you are 9 times more likely to die from being struck by lightning than from a snake bite.

As summer approaches, snakes become more active, making it more likely that your dog or cat will encounter one. Veterinarians say you can take the following steps to keep your pet safe.

  1. Snakeproof: Clear areas with thick undergrowth or grass around your home. These are areas where snakes like to hide. Keep the area around your home rodent-free since many snakes find mice and rats very tasty.
  2. Keep pets away from snakes: Try to keep your cat indoors. When walking a dog, always keep it on a leash. Pay attention if your dog suddenly starts barking at something, or if your pet starts to chase something.
  3. Don’t wait: If your pet has been in contact with a snake, bring it to the vet immediately. Even when bitten, pets may not show any visible signs of pain or injury. Snake venom can act fast—sometimes within less than one hour.
  4. Watch your pet: Some visible symptoms of snakebite in pets include wobbliness, collapsing, or vomiting. If you suspect a snakebite, take your dog or cat to a vet immediately.
  5. Identify the snake: If the snake that bit your pet is dead, bring it with you to the vet. This will help the vet to determine which treatment is correct. If the snake is not dead, do not kill it! This can put your own health at risk. Also, many snakes are shy and harmless. In some places, there may even be laws that protect certain species of snakes from being harmed.
  6. Learn pet first aid: Learn mouth-to-nose resuscitation in case your pet stops breathing. Do not use bandages on your pet. Since pets are usually bitten by snakes on their heads, necks, or chests, bandages can make it difficult for them to breathe.
Additional Resources

Read more about human and canine attitudes towards snakes at National Geographic and Discover.

Discover more about snakes at the San Diego Zoo and the Maine Department of Inland Fisheries and Wildlife.

Learn how you and your pet can stay safe around snakes at the National Park Service and U.C. Davis Health.

Images and Sources

Grass snake photo: Darius Bauzys
Grass snake photo license: Creative Commons 3.0

Northern water snake photo: Mdf
Northern water snake photo license: Creative Commons 3.0