5 Differences Between Snakes and Legless Lizards

Nope, that's not a snake. It's a glass lizard.
Nope, that's not a snake. It's a glass lizard.
Don Becker via Wikimedia Commons // CC BY-SA 3.0

If a limbless reptile like the one above crosses your path, it’s obviously a snake, right? Maybe not. Over the course of evolution, many different lizards have independently lost their legs. Today, we’re looking at the subtle differences that set these creatures apart from their serpentine brethren.

1. We've yet to find a legless lizard with a forked tongue.

Snakes have forked tongues—as do a fair number of lizards, including gila monsters, monitor lizards (such as the Komodo dragon), and South American tegus. When it comes to tracking down food, these pronged organs are incredibly useful. Here’s how they work: Wandering animals leave microscopic taste particles floating behind them in the air. Snakes and some lizards gather these up by flicking their forked tongues. After the tongue is drawn back into the mouth, the chemicals are delivered to a sensory apparatus called the vomeronasal organs. These help the reptiles figure out what sort of creature produced the taste particles in question. Although legless lizards are a diverse bunch, none that we know of feature this kind of tongue.

2. SNAKES DON’T HAVE EYELIDS, BUT SOME LEGLESS LIZARDS DO.

Snakes can’t blink (or wink, for that matter). Unlike us, the slithering reptiles don’t possess eyelids. Evolution’s given them a different way to protect their invaluable pupils. In the vast majority of species, a thin, transparent scale covers each eye. These are known as “spectacles” or “brilles” and, like most scales, they’re regularly replaced when the snake sheds its skin.

Numerous lizards—including most geckos—also have brilles instead of eyelids. However, many legless species sport the latter. For example, consider the so-called “glass lizards.” A widespread group, these lithe creatures can be found in Morocco, North America, and parts of Asia. Like snakes, glass lizards are essentially devoid of legs: Their forelimbs are completely gone while their rear legs have evolved into useless nubs that lie buried under the skin. Yet, unlike snakes, glass lizards do possess moveable eyelids.

3. NO KNOWN SNAKE HAS EXTERNAL EAR HOLES.

It’s often said that snakes are deaf. Over the past few decades, research has thoroughly disproved this notion, and we now know that the animals can easily detect certain airborne sounds. So where did the whole myth about snakes not being able to hear come from? Well, the misconception probably has something to do with the fact that snakes don’t have visible ear openings.

Most land vertebrates have both an eardrum and an inner ear. Snakes, on the other hand, lack the former. Their inner ears are connected directly to the jawbones, which usually rest against the ground. Whenever some other animal walks by, its footsteps inevitably produce vibrations. These travel through the earth and cause the snake’s jaw to vibrate in response. The inner ear then signals the brain, which interprets the data and identifies the source of the sound. Low-frequency noises that travel through the air can also be picked up in more or less the same manner.

Look closely at a snake, and you’ll notice that there aren’t any ear holes on the sides of its head. In contrast, most legless lizards have a pair. Then again, some varieties don’t. The Australian Aprasia lizards are adapted for a burrowing lifestyle—one that doesn’t really require external ear cavities. As such, most members of this genus lack these openings altogether.

4. SNAKE JAWS TEND TO BE A LOT MORE FLEXIBLE.

A lora, or parrot snake, eats an evergreen robber frog in Panama. Image credit: Brian Gatwicke via Wikimedia Commons // CC BY 2.0


 
Contrary to popular belief, snakes don’t unhinge or dislocate their jaws while feeding. They simply don’t need to. An average snake can swallow prey that are several times larger than its own head. This feat is made possible by an amazingly flexible set of jaws.

Just like in humans, a snake’s lower jaw consists of two bones called mandibles. Ours meet to form a chin, which is where the separate bones become fused. Snake mandibles aren’t joined together in this manner. Instead, the two lower jawbones can move independently of each other and can even splay apart to a considerable extent.

By comparison, the jaws of most legless lizards are far less maneuverable. As a result, they tend to eat proportionally smaller prey—but there’s an exception to this rule. Burton’s snake lizard (Lialis burtonis) is an unusual predator that specializes in eating other lizards. Bisecting the skull is a special hinge which enables the front of its snout to swing downwards. This gives Burton’s snake lizard enough oral flexibility to swallow fairly big prey whole. Recurved teeth and a muscular tongue help prevent the prey from escaping.

5. WHEN THREATENED, MANY LEGLESS LIZARDS CAN DISCARD AND RE-GROW THEIR TAILS.

If a snake, crocodilian, turtle, or tortoise loses its tail, the animal won’t be able to replace it with a new one. In the world of reptiles, that talent is reserved for lizards. Many—but not all—lizard species can famously lose a segment of their tail and then regenerate it (although the replacement is not as good as the original). This is no parlor trick: Out in the wild, it’s a potentially life-saving maneuver. Should a predator seize a lizard by the tail, the whole appendage can break off. Afterward, this discarded appendage might flail and spasm, distracting the attacker long enough for our lizard to escape. Check out some graphic images of a glass lizard sans tail.

There’s a correlation between a legless lizard’s habitat and the length of its tail. Species that burrow through dirt or spend most of their time submerged in sand have relatively short tails. In contrast, those that live at the surface have rather long ones. Why is this? To lizards with subterranean habits, lengthy tails can be a nuisance because they create excessive drag during digs. Up above the soil, however, a really long tail reduces the odds of some predator snagging a more vital part of the body.

10 of the Best Indoor and Outdoor Heaters on Amazon

Mr. Heater/Amazon
Mr. Heater/Amazon

With the colder months just around the corner, you might want to start thinking about investing in an indoor or outdoor heater. Indoor heaters not only provide a boost of heat for drafty spaces, but they can also be a money-saver, allowing you to actively control the heat based on the rooms you’re using. Outdoor heaters, meanwhile, can help you take advantage of cold-weather activities like camping or tailgating without having to call it quits because your extremities have gone numb. Check out this list of some of Amazon’s highest-rated indoor and outdoor heaters so you can spend less time shivering this winter and more time enjoying what the season has to offer.

Indoor Heaters

1. Lasko Ceramic Portable Heater; $20

Lasko/Amazon

This 1500-watt heater from Lasko may only be nine inches tall, but it can heat up to 300 square feet of space. With 11 temperature settings and three quiet settings—for high heat, low heat, and fan only—it’s a dynamic powerhouse that’ll keep you toasty all season long.

Buy it: Amazon

2. Alrocket Oscillating Space Heater; $25

Alrocket/Amazon

Alrocket’s oscillating space heater is an excellent addition to any desk or nightstand. Using energy-saving ceramic technology, this heater is made of fire-resistant material, and its special “tip-over” safety feature forces it to turn off if it falls over (making it a reliable choice for homes with kids or pets). It’s extremely quiet, too—at only 45 dB, it’s just a touch louder than a whisper. According to one reviewer, this an ideal option for a “very quiet but powerful” heater.

Buy it: Amazon

3. De’Longhi Oil-Filled Radiator Space Heather; $79

De’Longhi/Amazon

If you prefer a space heater with a more old-fashioned vibe, this radiator heater from De’Longhi gives you 2020 technology with a vintage feel. De’Longhi’s heater automatically turns itself on when the temperatures drops below 44°F, and it will also automatically turn itself off if it starts to overheat. Another smart safety feature? The oil system is permanently sealed, so you won’t have to worry about accidental spills.

Buy it: Amazon

4. Aikoper Ceramic Tower Heater; $70

Aikoper/Amazon

Whether your room needs a little extra warmth or its own heat source, Aikoper’s incredibly precise space heater has got you covered. With a range of 40-95°F, it adjusts by one-degree intervals, giving you the specific level of heat you want. It also has an option for running on an eight-hour timer, ensuring that it will only run when you need it.

Buy it: Amazon

5. Isiler Space Heater; $37

Isiler/Amazon

For a space heater that adds a fun pop of color to any room, check out this yellow unit from Isiler. Made from fire-resistant ceramic, Isiler’s heater can start warming up a space within seconds. It’s positioned on a triangular stand that creates an optimal angle for hot air to start circulating, rendering it so effective that, as one reviewer put it, “This heater needs to say ‘mighty’ in its description.”

Buy it: Amazon

Outdoor Heaters

6. Mr. Heater Portable Buddy; $104

Mr. Heater/Amazon

Make outdoor activities like camping and grilling last longer with Mr. Heater’s indoor/outdoor portable heater. This heater can connect to a propane tank or to a disposable cylinder, allowing you to keep it in one place or take it on the go. With such a versatile range of uses, this heater will—true to its name—become your best buddy when the temperature starts to drop.

Buy it: Amazon

7. Hiland Pyramid Patio Propane Heater; Various

Hiland/Amazon

The cold’s got nothing on this powerful outdoor heater. Hiland’s patio heater has a whopping 40,000 BTU output, which runs for eight to 10 hours on high heat. Simply open the heater’s bottom door to insert a propane tank, power it on, and sit back to let it warm up your backyard. The bright, contained flame from the propane doubles as an outdoor light.

Buy it: Amazon

8. Solo Stove Bonfire Pit; $345

Solo Stove/Amazon

This one is a slight cheat since it’s a bonfire pit and not a traditional outdoor heater, but the Solo Stove has a 4.7-star rating on Amazon for a reason. Everything about this portable fire pit is meticulously crafted to maximize airflow while it's lit, from its double-wall construction to its bottom air vents. These features all work together to help the logs burn more completely while emitting far less smoke than other pits. It’s the best choice for anyone who wants both warmth and ambiance on their patio.

Buy it: Amazon

9. Dr. Infrared Garage Shop Heater; $119

Dr. Infrared/Amazon

You’ll be able to use your garage or basement workshop all season long with this durable heater from Dr. Infrared. It’s unique in that it includes a built-in fan to keep warm air flowing—something that’s especially handy if you need to work without wearing gloves. The fan is overlaid with heat and finger-protectant grills, keeping you safe while it’s powered on.

Buy it: Amazon

10. Mr. Heater 540 Degree Tank Top; $86

Mr. Heater/Amazon

Mr. Heater’s clever propane tank top automatically connects to its fuel source, saving you from having to bring any extra attachments with you on the road. With three heat settings that can get up to 45,000 BTU, the top can rotate 360 degrees to give you the perfect angle of heat you need to stay cozy. According to a reviewer, for a no-fuss outdoor heater, “This baby is super easy to light, comes fully assembled … and man, does it put out the heat.”

Buy it: Amazon

Sign Up Today: Get exclusive deals, product news, reviews, and more with the Mental Floss Smart Shopping newsletter!

This article contains affiliate links to products selected by our editors. Mental Floss may receive a commission for purchases made through these links.

Why Do Dogs Like to Bury Things?

Dogs like to dig.
Dogs like to dig.
Nickos/iStock via Getty Images

If you’ve ever found your dog’s favorite toy nestled between pillows or under a pile of loose dirt in the backyard, then you’ve probably come to understand that dogs like to bury things. Like many of their behaviors, digging is an instinct. But where does that impulse come from?

Cesar's Way explains that before dogs were domesticated and enjoyed bags of processed dog food set out in a bowl by their helpful human friends, they were responsible for feeding themselves. If they caught a meal, it was important to keep other dogs from running off with it. To help protect their food supply, it was necessary to bury it. Obscuring it under dirt helped keep other dogs off the scent.

This behavior persists even when a dog knows some kibble is on the menu. It may also manifest itself when a dog has more on its plate than it can enjoy at any one time. The ground is a good place to keep something for later.

But food isn’t the only reason a dog will start digging. If they’ve nabbed something of yours, like a television remote, they may be expressing a desire to play.

Some dog breeds are more prone to digging than others. Terriers, dachshunds, beagles, basset hounds, and miniature schnauzers go burrowing more often than others, though pretty much any dog will exhibit the behavior at times. While there’s nothing inherently harmful about it, you should always be sure a dog in your backyard isn’t being exposed to any lawn care products or other chemicals that could prove harmful. You should also probably keep your remote in a safe place, before the dog decides to relocate it for you.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.