No doubt the last time you saw a snake in a movie, they showed the snake hissing—and displaying their forked tongue. Their tongue is instantly recognizable, but why is it so different from humans?
Forked tongues help snakes to detect chemicals (smells) around them. Instead of sniffing, they flick their tongue out to physically catch water-borne chemicals in the air. They then bring their tongue back into their mouth, and use their vomeronasal organ to learn what’s around them.
This isn’t unique to snakes as it’s a common trait shared by many reptiles. And there’s an excellent reason why their tongue is split in two.
Why do Snakes Have Forked Tongues?
So, why do snakes poke out their tongues? The real reason snakes have forked tongues is because it helps them to smell the air around them. The fact that their tongue has more surface area helps them pick up more chemicals from the environment around them.
Their whole sense of smell is based on their having a forked tongue. The vomeronasal organ in the roof of their mouth has a bulb on each side, and the snake will align their tongue so that each side of the fork touches one of the bulbs.
Is there any point to that? According to the Journal of Comparative Psychology, there is. The fact that their tongues are forked, and that they have two different bulbs in their vomeronasal organ, means that they can locate the source of smell far better than humans.
If the snake picks up more chemical cues from prey on one of the forks of their tongue, they can make a reasonable bet that the prey is in that direction.
It’s a little like listening to something in stereo. You don’t need to think about it, but you can immediately tell whether the sound came from the left or the right. A snake’s sense of smell works in the same way. So, what benefits does this give to the snake?
- The snake can track down prey using their sense of smell alone. Their sense of hearing isn’t great. They can only ‘hear’ vibrations in the ground, because they don’t have ears. And their sense of sight isn’t as focused as humans, either. Their sense of smell is highly developed.
- The snake can smell predators in their immediate vicinity, too. By sensing predators and the direction they’re coming from, the snake can head to a safe spot, e.g., further up a tree or hidden underneath loose sand.
So, why don’t snakes use their nostrils to smell, like most other animals of their size? It’s not clear, but we can guess. The most likely reason is that sniffing the air can be quite loud.
Many snakes rely on camouflage when they’re hunting or hiding from predators, and sniffing may be just loud enough that they would give away their position. Sniffing would also make their chest rise and fall, whereas poking the tongue out ever so slightly wouldn’t.
Why Do Only Snakes Have Forked Tongues?
Many different reptiles have forked tongues, not just snakes. But since they’re so beneficial, why don’t we have forked tongues? Because we have many senses that we use to detect any prey and predators around us. Our sense of sight, for example, is much better than a snake’s.
That’s because we have something called a foveal pit at the back of our eye. This is a small bump that helps us to focus our vision on minute things, like the text you’re reading right now. Snakes don’t have one of these, so their vision is, comparatively, blurrier. Our sense of hearing is better than a snake’s, too.
And what about other animals like dogs, which also rely on their sense of smell? According to PBS, dogs have developed their own way of improving their sense of smell. Rather than using a forked tongue, dogs rely on 300 million olfactory receptors (chemical detectors) in their nose, which is far more than other animals (we only have six million, for example).
A dog doesn’t need a forked tongue because their sense of smell is already so good. Snakes lack these developed olfactory receptors, and use their tongue instead.
What Is a Snake’s Tongue Called?
A snake’s tongue is just called a tongue. Each ‘fork’ of the tongue is called a tine. Tine is a word that generally refers to the individual sharp prongs on something, for example, the forks we eat with, rakes, combs, antlers and so on. The word tine is of ancient origin, dating back to the 12th and 13th centuries. As you can probably guess, it’s rarely used today.
Do Poisonous Snakes Have Forked Tongues?
First of all, snakes aren’t either poisonous or non-poisonous. The correct term is ‘venomous’. A poison is something which kills you if you eat it, whereas venom is something that kills you if it enters your bloodstream. Because snakes inject a toxic substance into your blood through their fangs, it’s referred to as venom, and snakes are referred to as venomous.
Either way, is it just venomous snakes that have forked tongues? No, every snake has a forked tongue, as do most species of reptile. A forked tongue, therefore, isn’t a sign of how venomous a snake is. If you do want to tell the difference between a venomous and a non-venomous snake, there are a few ways to do so. They include:
- Head shape. Venomous snakes generally have wider heads, because to the rear of their heads they need venom glands on each side.
- Eye shape. Most venomous snakes have what look like angry eyes, while nonvenomous snakes have rounded eyes.
- Pupil shape. Nonvenomous snakes usually have rounded pupils, while venomous snakes have pupils like those of a cat (more like slits).
- Non-venomous snakes don’t usually have two long fangs at the front of their top jaw.
- Color and pattern. Venomous snakes often have striking color patterns to warn predators and threats that they’re dangerous. There are notable exceptions, though, like the non-venomous milk snake—which has evolved to look a lot like the highly dangerous coral snake.
But despite all these differences, both venomous and non-venomous snakes have forked tongues. Non-venomous snakes have to find prey using their sense of smell too, remember.
Do Snakes Smell Through Their Tongues?
To be clear, snakes don’t smell through the tongue itself. Their tongue, physically, is little different to ours. It’s pure muscle, and lacks any of the mechanisms necessary to ‘smell’ anything. But that doesn’t mean that it isn’t a vital part of the scent detection process.
As snakes move through their environment, they need a way to draw smells in as they go. Rather than sniffing the air, the snake will poke out their tongue. Chemicals in the air actually stick to the snake’s tongue, which they then draw into their mouth. The snake will repeatedly poke their tongue out if they’re searching for something nearby, or feeling threatened, as they’re trying to pick up a scent.
The tongue presses up against the roof of the snake’s mouth. Here, their vomeronasal organ picks up the chemicals and analyzes them; the snake can then tell whether they can smell prey, a predator, or something else. The vomeronasal organ works just like our sense of smell, picking up on large moisture-borne chemicals in the air.
What Does a Forked Tongue Symbolize?
The idea of a forked tongue is best known through the phrase to ‘speak with a forked tongue.’ This phrase essentially means that a person is lying, the idea is that you say one thing to one person, and another thing to somebody else. It, therefore, means the same as being two-faced. The origin of the phrase is actually Native American, and was adopted across the U.S. from the 1800s onwards.
The initial popularity of the phrase was amplified by our pre-existing notions of snakes. Through religion, the most common association we make with snakes is deceit—the serpent, after all, being the symbolic tool of evil that tempted Eve in the Garden of Eden. This, therefore, reinforces the idea of snakes being cruel, deceitful and maybe even evil.
This idea also plays out in movies, television and other forms of media. Snakes are a recognizable symbol of deceit in books like the Harry Potter series and the Jungle Book, for example, and the movie adaptations of the same. In these, the snakes will hiss and flick their tongues to show how menacing they are. Of course, actual snakes aren’t any more or less evil than other animals. Plenty of people find snakes scary, of course; but in reality, their tongues don’t have any special meaning.