These reptiles are the subject of many an urban legend, some of which aren’t too far removed from reality. Others—like the widely-believed myths listed below—are off by a mile. 

1. They Dislocate Their Lower Jaws While Feeding.

Watch this huge African rock python gulp down an entire antelope (unless you’re squeamish and/or a hoofed mammal). How could any animal engulf something that’s bigger than its own head? Popular wisdom holds that serpents can do so by detaching their jaws. The truth is easier to swallow. 

Flexibility, not dislocation, is the name of the game. A snake’s lower jaw is split into two halves called “mandibles.” At rest, their tips touch to form the snaky equivalent of a chin. Yet, these bones aren’t fused together like ours are. Instead, a stretchy ligament connects the mandibles and enables them to separate once dinner starts. Similar equipment enhances the upper jaw’s maneuverability as well. 

2. You Can Tell a Rattlesnake’s Age by Counting its Rattles.

This premise makes two false assumptions: A) the critters get exactly one new rattle each year and B) existing rattles are never lost. Let’s start with the first claim. After each shedding of the skin, rattlesnakes obtain another tail bulb. But, for babies and juveniles, that event can take place as often as every few weeks. In contrast, elderly specimens might only shed on a bi-annual basis. Moreover, rattles don’t last forever—over time, they become prone to breaking off. 

3. Certain Snakes Are “Poisonous.”

Though people tend to use them interchangeably, "poisonous" and "venomous" aren't synonyms. Poisons work by getting eaten, inhaled, or absorbed through the skin. Venom, on the other hand, is any toxic substance that gets injected into its target via fang, stinger, etc. Poisonous snakes are incredibly rare, with the Asian tiger keelback (Rhabdophis tigrinus)—which stores toxins in special glands on its neck—being among the few documented examples. On the other hand, more than 600 venomous species are currently at large.   

4. Snakes Are Slimy.

Amphibians secrete mucous all over their skin. Ergo, most frogs and toads have wet, slippery hides. Snakes, being reptiles, do nothing of the sort. Instead, they’re covered with dry scales, and can feel like smooth sand running through your fingers when held. 

5. Cottonmouths Can’t Bite Underwater.

When your scientific name (Agkistrodon piscivorus) literally means “hooked-toothed fish-eater,” people naturally assume that you spend a lot of time in and around water. This assumption isn't wrong: throughout the American southeast, these semiaquatic predators are a common sight. However, familiarity doesn’t always breed understanding. Despite their knack for hunting prey while submerged, one dangerous myth claims that cottonmouths can’t strike underwater. They can and do. So, whether you’re out hiking or going for a dip, please exercise caution around them. 

6. They’re Mostly Tail.

Here’s an inside look at a generalized snake. As you can see, serpentine survival depends on numerous vital organs (housed between two rows of ribs). Notice that empty, white area near the end? That’s the tail, which usually doesn’t even take up a fifth of the snake’s total body length. Regardless, it can still take on important functions. Consider the aptly-named spider-tailed viper, whose tail tip apparently lures over arachnid-eating birds because it comes with long, skinny scales that resemble spider legs.    

7. Snakes are deaf.

Since they lack eardrums, naturalists once thought that our serpentine friends couldn't hear airborne noises. Fairly new research disproves this. Snakes still possess inner ears, which connect to their jawbones. While resting or slithering, they can sense vibrations in the ground (such as footsteps). Once vibrations are picked up by the jaw, the soundwaves are sent to the brain and processed.

So what about vibrations that pass through the air? In 2011, biologist Christian Christensen monitored the brains of a few ball pythons (Python regius). As he discovered, his test subjects had no trouble hearing low-frequency airborne sounds because their skulls vibrated in accordance with them. However, Christensen’s pythons weren’t as sensitive to higher-pitched noises. 

While further research may disprove this theory, it is generally believed that cobras sway to the music of snake charmers not because of the sounds emanating from their instruments, but because the animals interpret the flute in motion as a potential threat.  

8. Milk Snakes Drink … Well, Milk.

One can find folks who genuinely believe that these harmless little guys will grab onto cow udders and start chugging milk (hence their common name). Obviously, this doesn’t happen. For starters, reptiles can’t digest dairy products. Also, a typical bovine wouldn’t blithely stand still as needle-like teeth dug into a rather sensitive area.

9. Rattlesnakes Always Rattle Before Lashing Out.

Snakes may not be the spiteful villains you see in cartoons, but when danger strikes, they sometimes can’t help but strike back. Rattlers warn potential attackers by vibrating their trademark tails. But here’s the thing: they don’t have to sound the alarm. On occasion, they’ll just skip the rattling entirely. Always tread carefully through rattler country. 

10. Baby Snakes Inject More Venom Than Adults Do. 

Technically, the jury’s still out on this one, but scientists lack any compelling evidence to support it. Old-school rumors assert that, among venomous species, babies deliver more potent bites because they haven’t yet learned self-control and will inject far more venom than necessary. Seasoned adults, meanwhile, are said to use more conservative doses. 

No study has yet verified that snakes consciously dictate how much venom they dish out. Furthermore, even a small nip from a full-sized specimen probably expels more of the stuff than the biggest bites from hatchlings of the same species ever could. 

11. Constrictors asphyxiate their prey.

Last week, a new paper—published in The Journal of Experimental Biology—put the strangulation theory to rest for good. Boas and pythons have long been accused of fatally choking their victims. But it turns out that they actually kill by halting blood flow. Dr. Scott Boback and his colleagues deduced as much by measuring constriction’s effects on the heart rate, blood iron balance, blood gasses, and blood pressure of anesthetized rats. Within seconds, the team learned, an ordinary boa can wrap tightly enough around its next meal to stop circulation altogether.