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.

What’s Better Than a Dog in a Sweater? A Sweater That Shows an Image of Your Dog in a Sweater

Sweater Hound
Sweater Hound

If you think the sight of someone walking their sweater-clad dog is just about the cutest thing in the world, you’re absolutely correct. But what if that person was wearing a sweater that showed an image of their dog wearing a sweater? If you think that sounds even cuter, you’re in for a treat.

According to People, New York-based apparel company Sweater Hound will knit you a sweater that displays an image of your dog in a sweater—all you have to do is submit your favorite photo of your dog. And, because not all dogs love wearing sweaters in real life, your dog doesn’t have to be wearing a sweater in the photo you upload.

Each sweater is made from a combination of acrylic and recycled cotton, and will prove to your pet that you truly do love them more than anyone else (unless you already own sweaters emblazoned with the faces of your friends and family).

The sweaters, which cost $98 each, come in both child and adult sizes, and you can choose between cream, navy, black, and gray. The options don’t stop there—Sweater Hound offers sweaters that show your dog wearing just a bow tie, a bow tie and a sweater, a Santa hat and scarf, reindeer ears and a sweater, or even a “Super Dog” cape and domino mask outfit.

sweater hound dog wearing a bow tie on a sweater
Sweater Hound

If sweaters aren’t really your style, there are also hoodies and sweatpants decorated with a smaller, logo-sized image of your dog. Or, you could snuggle with your prized pooch underneath a warm blanket bearing a rather giant image of said pooch.

blanket with an image of a dog wearing a bow tie and sweater
Sweater Hound

While the company does specialize in creating dog-related products, they’ll do their best to accommodate people who love salamanders in Santa hats, birds in bow ties, and other pets wearing clothes. You can email them at Hello@Sweaterhound.com to discuss your options.

If you’re hoping to get someone a gift from Sweater Hound this holiday season, you should act fast: You have to place your order by December 4 in order to guarantee delivery before Christmas, and that date will likely change as the days go by.

Adorable, customizable clothing is just one of the many perks of being a dog owner—here are 10 more scientifically proven benefits.

[h/t People]

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Move Over Dogs, Goats, and Peacocks: Llamas Are the Hot New Therapy Animal

jensenwy/iStock via Getty Images
jensenwy/iStock via Getty Images

Possibly because Dasher, Dancer, Prancer, and the rest of the reindeer are pretty busy at this time of year, Kimpton Hotel Monaco in Portland, Oregon, is offering guests the chance to hang out with a few jolly llamas instead.

The Washington Post reports that the friendly, festively dressed llamas belong to Mountain Peaks Therapy Llamas and Alpacas, which usually brings them to hospitals, rehabilitation centers, senior communities, hospice care, special-needs organizations, and even schools. According to the organization’s website, the visits help “alleviate loneliness, lower blood pressure, and reduce stress.”

And, though the clinical benefits to the Kimpton’s guests haven’t been proven, hotel manager Travis Williams confirms that everyone definitely loves spending time with the quirky quadrupeds. Last year, after overwhelmingly positive reactions to the llama visits, the hotel decided to bring them back.

“Once we saw the joy that it brought people, we just kept going,” Williams told The Washington Post.

While it might seem like the use of llamas for therapy is a characteristically Portland-ish idea, it’s not the only place you can find them. The New York Times reports that 20 llamas and alpacas are registered with Pet Partners, a national nonprofit organization for therapy animals, and many others are owned and trained by private family farms across the country.

Jeff and Carol Rutledge, for example, have 13 llamas and alpacas on their property in Stockdale, Texas, outside San Antonio. Three of them are registered therapy animals, having passed a test that includes being touched by strangers and staying unaffected while people argue near them.

During their visits to assisted living facilities, veterans’ homes, and other events in the area, the Rutledges have observed the animals having a profound effect on residents’ behavior. One man, who is nonverbal and recovering from a motorcycle accident, will murmur as he grooms one of the llamas. And the Rutledges’ high-school-aged daughter, Zoe, even did a science experiment for her 4-H club that showed the residents’ blood pressure is lower after visiting with the llamas.

While there’s not a very high chance of seeing therapy llamas in airports just yet, you might be lucky enough to see something a little smaller—like LiLou, San Francisco International Airport’s first therapy pig.

[h/t The Washington Post]

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