Why Do Snakes Hiss?

Among their weapons are fear and surprise and a ruthless efficiency...uh, sorry, allow me to begin again—it appears I've got my pythons mixed up! (For the uninitiated, that was a quote from a sketch by comedy troupe, Monty Python.) All right, so let's talk snakes. Specifically, I'd like to discuss one of their characteristic traits—that menacing hiss. Just why do they do it? Read on!

The Snake's Defense

Among their weapons are intimidation and fear. This is usually what a human feels when confronting a dangerous snake, but the truth of the matter is that snakes are more afraid of us than we are of them. And for good reason, as humans are only one of the many natural "enemies" which snakes are forced to contend with! This leads us to the first reason why they hiss: because they have predators who want to kill them and hissing is one of a number of defenses snakes use to protect themselves. Oddly, even though all snake species have the physiological propensity to hiss, in actuality, most snakes remain silent. Perhaps they believe hissing is impolite?

How Do Snakes Hiss?

Snakes breathe through an organ in their throat just behind the tongue called the glottis. When breathing normally, the glottis opens and closes into the trachea (windpipe.) The reptile glottis (unlike those of mammals) always remains closed, thus forming a vertical slit, until the snake takes a breath. A snake can forcibly expel air from the glottis making a small cartilage piece just inside the glottis vibrate. This is how a snake makes its characteristic hissing sound. Amazingly the glottis can be extended out the side of the snake's mouth while consuming large prey, thus allowing the snake to breathe.

To Hiss or Not to Hiss

Hissing is a very intimidating sound which has its benefits, like dissuading would be predators and making a snake appear larger in the eyes of its enemy! However, large venomous snakes, constricting snakes, and poisonous snakes do not have to rely on hissing for defense as their sheer size or venom speak for themselves. Even so, sometimes (but not always), boa constrictors and other snakes can and will hiss when annoyed, and let's face it, a hiss from a large snake will make anyone think before attacking!

Not The Social Snake

It's important to understand that snakes don't hiss in order to communicate with other snakes as they're not social reptiles. The only times you'll find snakes together are when they're breeding or hibernating. Also, their ability to hear airborne sounds is minimal at best and the only other snake known to emit sounds (very low pitched growls, in fact) are King Cobras. Why they emit these sounds, though, remains unknown.

So What Snakes DO Hiss?

Very small snakes rarely hiss as a defense because hissing is mostly a technique used for intimidation, so is best suited to larger snakes. The best hissers in the world are considered to be the Pine Snake (and their relatives), with a close second going to Hognose Snakes. Both of these species do not rely solely upon hissing but also incorporate several defensive behaviors which include striking as well as visual displays which exaggerate their size when they are threatened! Other snakes known to hiss among the North American varieties are Cottonmouths, Bull, and Gopher snakes.

So if you come across a snake and it hisses at you, use some caution and common sense! Back away before that hiss turns to shove—as that shove will certainly prove to be a lot more unpleasant.

By Tom Matteo