Fall 2021 Children's Sneak Previews

Snakes: Super Senses, Stretchy Jaws And Deadly Venom

Discover why snakes stick their tongues out at you, whether they really dislocate their jaws to eat, how many ways there are to slither and much more.

Where do snakes live?

Snakes have evolved to survive in a huge variety of habitats.

Some live in deserts or dry plains, others are master tree-climbers that thrive in forests, while many spend most of their lives burrowing in soil. Then there are sea snakes, which are adapted to spend most of their lives in the ocean. Anacondas are some of the world's biggest snakes and they spend lots of time in water too. Their eyes and nostrils have evolved to be on top of their heads – an adaptation that lets them see and breath while keeping the rest of their body submerged.

Snakes live almost everywhere but you won't find them in the coldest parts of the world, including Antarctica, Greenland and Iceland.

Land snakes are also missing from some warmer island countries, such as Cape Verde, Tuvalu and Kiribati. But these islands aren't entirely snake-free. Sea kraits sometimes come ashore to lay their eggs. Occasionally non-native species have been found on isolated islands, most likely having been accidentally carried in on boats or in shipping containers. 

Arabian sand boas are desert dwellers. Unlike most snakes, their eyes are on top of their heads rather than to the sides. This lets them sit just under the surface of the sand with just their eyes stuck out like little periscopes. © Dan_Koleska/ Shutterstock

Do snakes have bones?

Snakes have lots of bones, but fewer types of bones than us. As well as their skull, they have 100–400 vertebrae in their spine and up to 200 more in their tail. Adjoining from most of these backbones are a pair of ribs that can often move independently of each other.

Movable ribs let many snakes expand their bodies to make room for large food items. Snakes haven't got a diaphragm, so they also move their ribs to create the changes in pressure needed to breathe. Cobras use their 'neck' ribs to flare their iconic hoods too. 

Snakes might have more bones than us, but they have fewer types of bones. They only have a skull, vertebrae and ribs.

How do snakes move?

Snakes don't have arms or legs, so they slither around on their bellies. They mostly rely on friction against irregularities on surfaces, such as rocks, grass or tree bark, to push and pull themselves along. Surfaces where they can't get traction pose a challenge – a snake would struggle to move well on a super smooth floor, for example.

Most snakes move in a wavelike S-pattern. As they weave side-to-side, they subtly use their loops to push themselves off the ground to move forwards. 

Sea snakes and sea kraits undulate in an S-pattern, weaving their way through the water. They propel themselves with flattened, paddle-like tails. © Rich Carey/Shutterstock

Some can also use a concertina-like movement. They anchor one part of their body and then pull or push with their other sections to shunt themselves along. Some snakes use this motion, aided by their flexible skeletons and strong muscles, to help them scale trees with relative ease.

There are snakes that can move in an almost completely straight line – this type of movement is known as rectilinear motion. These snakes anchor their belly scales at several points along their body and use them to very slowly pull the sections in between forwards along the ground.

Then there are sidewinder snakes. These move at an angle, lifting part of their body off the ground while keeping the part in contact with the floor still and pushing left or right. As they pick up and place down their bodies, they leave a discontinuous series of tracks. This style of movement is often used on loose ground, such as sand.  

Peringuey's desert adder is a sidewinding species found on the sand dunes along the Namibian and southern Angolan coasts. © Chantelle Bosch/ Shutterstock

Snakes can't fly, but some, such as the paradise tree snake, can move from tree to tree by leaping off branches, flattening their bodies and gliding.

Many snakes burrow headfirst in sand or soil, some generating high forces to achieve this.

What do snakes eat?

All snakes are carnivores. Their diets range from large mammals to birds, fish, insects, earthworms, eggs, slugs and snails.

Other carnivores, such as lions, use sharp teeth to tear into animal carcasses. But snakes can't tear their food or even chew – they don't have the type of teeth and muscles required for that. Instead, snakes swallow their dinners whole. 

Our snake researcher Marion Segall breaks down the myth that snakes dislocate their jaws to eat. 

Snakes that eat very large prey don't unhinge or dislocate their jaws to eat – their mouths are just really stretchy. The lower jaw is made up of two parts that are joined by a ligament. The back of each of these parts is attached to the top of the skull via another mobile joint. This allows the snake to stretch the sides of their lower jaw apart when they need to open their mouth really wide.

Most snakes' skulls are generally very flexible – they're made up of approximately 30 bones, some of which can move independently of each another. This lets them 'walk' their head up around their dinner to edge it slowly down their throats. Some combine this with backwards-curving teeth that hook into their food and prevent it from slipping back out of their mouth.

Big snakes are known to occasionally eat enormous meals. Among the largest recorded was a 59-kilogramme impala eaten by a 4.87-metre-long African rock python. But they have limits – rangers in the Everglades National Park, USA, once discovered 3.9-metre-long Burmese python that had burst while trying to eat a 1.8-metre alligator.

Man-eating snakes are incredibly rare. Most victims are babies or young children, though a few adults have met this grisly fate too. In recent years, a 25-year-old and a 54-year-old were both swallowed by seven-metre-long pythons in Sulawesi, Indonesia. 

Snakes have flexible skulls and super stretchy mouths that help them to swallow large meals. © Butterfly Hunter/ Shutterstock

Are snakes poisonous?

Almost all snakes that produce toxins are venomous rather than poisonous. To get into a victim's bloodstream, venom enters through a wound, such as a bite or sting. Poison doesn't – it can be absorbed through the victim's skin or digestive system, or even inhaled.

Venomous snakes make venom in glands in their heads and deliver it through a bite with needle-like fangs. Vipers and cobras inject their venom through hollow teeth. In other groups of snakes, the teeth can be solid or have a deep groove that acts as a channel for venom. The shape of the fangs varies depending on what the snake prefers eating. Some cobras can also spit their venom considerable distances, often aiming for a threat's face for maximum damage.

Venom evolved in snakes to help them hunt. Some will use it to defend themselves too. The toxins' effects typically depend on the type of snake – some venoms damage muscle, others nervous tissue or blood.

Snakes can't chew to process their food, but in rear-fanged snakes some species will gnaw on their prey, which releases their venom. These toxins may subdue their prey and help with digestion. 

Many colubrid snakes don't pose much of a threat to people. Africa's boomslangs are one of the exceptions. These rear-fanged snakes can deliver potentially deadly bites. © Travel_photography_Timo/ Shutterstock

There are a few poisonous snakes too. These animals sequester poison or distasteful chemicals from the animals they eat and repurpose them as a deterrent within their own bodies.

One example is the North American garter snake. These eat rough-skinned newts, which have tetrodotoxin in their skin – that's the same deadly chemical that's in pufferfish and blue-ringed octopuses. Garter snakes are resistant to tetrodotoxin's effects and will harbour the chemical in their own bodies in amounts that could kill or incapacitate their own predators.

Some keelback snakes sit on both sides of the fence, using poison they sequester from toads as a venom. The toad poison is absorbed into the snake's blood, then secreted through their salivary glands and delivered through a bite.

Are snakes blind?

Most snakes have specialised, almost transparent scales called spectacles covering their eyes, but they can still see. Unlike most of their lizard relatives, snakes don't have eyelids. In fact, in the UK, blinking is one of the clues that helps us tell slow worms – a type of limbless lizard – and snakes apart.

A snake's vision matches its lifestyle and can be quite important. For example, some species have very large eyes, and some have evolved ultraviolet-blocking lenses that help them to see clearly and hunt in bright sunlight.

But eyes aren't the only organs that help a snake catch its dinner. Some have nerve endings in specialised pits in their faces that let them 'see' into the infrared spectrum and pick up heat signals from prey. This can help them hunt in the dark. 

Some snakes have pit organs that let them sense infrared radiation. These can look like a series of holes in the snake's face. © Maris Grunskis/ Shutterstock

Chemical sensing is generally important to snakes, sometimes more so than eyesight. Snakes have forked tongues that they flick in and out of their mouths. By sticking their tongue out, they pick up odour molecules from their environment. When they retract their tongue, the molecules pass into the vomeronasal organ in the roof of their mouth, delivering smell information to the brain.

Do snakes have ears?

Snakes don't have an external opening to their ear or eardrums, but they do have the same parts of the middle and inner ear that we do. Although they lack outer eardrums, they can still hear via vibrations transmitted through the body and head. The inner ear also helps with their sense of balance.

Why do snakes shed their skin?

Snakes are covered in scaly skin made of keratin that can be very colourful and even iridescent. Scales are tough and help protect the snake from damage from its environment, predators and feisty prey. They can also act as a barrier that reduces the loss of water.

Snakes regularly moult to allow for growth, repair damage and remove parasites. They grow a new layer of skin under the old one and then secret fluid between the two. The snake then breaks through the old skin and works its way out of it, revealing the new, polished skin. 

Some snakes have smooth scales. Others, such as this Eastern diamondback rattlesnake, have keeled scales, which have a ridge down the centre. Their rattles are made up of modified, hollow scales.  © Chase D'animulls/ Shutterstock

Snakes' scales vary in size and shape depending on where on the body they are, the species and their lifestyle.

Rattlesnakes, for example, have modified scales at the end of their tails that form a set of interlocking segments. They vibrate these to create a rattling sound as a warning to nearby threats. In contrast, the spider-tailed horned viper uses its tail as a lure – it's shaped like a spider to attract the snake's next meal.

Some snakes are camouflaged, using the colours and patterns of their scales to blend in with their environment.

Others use bright colours as a warning to predators. Venomous Eastern coral snakes, for example, feature bold bands of black, red and yellow. Some less dangerous snakes have evolved patterns similar to those of dangerous species as a deceptive self-defence tactic – this is known as Batesian mimicry. Scarlet kingsnakes are well known, harmless mimics of Eastern coral snakes, for example. 

Eastern coral snakes use bright colours to tell threats to keep their distance. This is known as aposematism. © Patrick K. Campbell/ Shutterstock

Are snakes endangered?

The International Union for Conservation of Nature lists more than 120 species of snake as Endangered or Critically Endangered.

Emerging diseases, such as snake fungal disease, caused by the fungus Ophidiomyces ophiodiicola, are among the threats. Some scientists have drawn cautionary parallels between this disease's sometimes-fatal infections and the devastating spread of chytridiomycosis in amphibians.

But it's people that are at the root of many of snakes' problems. The threats we pose include habitat destruction through agricultural expansion, resource extraction and building, as well as through the effects of climate change.

Some snakes are also harvested by people as a source of exotic meat, as well as for their skin, which is turned into leather.

In some places, rattlesnakes are intentionally persecuted in recreational 'round-ups'. These grisly festivals are dedicated to capturing, beheading and skinning the reptiles, sometimes under the guise of promoting awareness and safety around wild venomous snakes.

Our actions threaten snakes' ability to survive and can alter their distributions, bringing them into contact and conflict with people more often.

In the UK, our snakes and other reptiles are protected by the Countryside and Wildlife Act 1981, which makes it illegal to kill or injure them. Discover which snakes you might be lucky enough to spot out and about in the UK and how to identify them. 

Snakes, Lizards, Spiders Coming — Monthly — To Pittsburgh Mills In Reptile Show & Sale

Anyone who has never had the chance to see an axolotl up close is in luck.

The slippery little aquarium creature, made popular by the Minecraft video game craze, will be on display at the Pittsburgh Reptile Show & Sale making its new home at the Pittsburgh Mills in Frazer.

"They're really cute. They look like they're smiling," said Amanda South, the event organizer.

Snakes, lizards, frogs and spiders will be slithering and jumping into the mall once a month, bringing up to 1,500 people to buy, sell, trade and learn about exotic animals.

The Pittsburgh Reptile Show & Sale, in business since 1989, was forced to move after fire destroyed its former longtime showroom at the Harmar House.

"We are so excited about the new place, and we plan to bring some life into the mall," South said.

"It's not just, like, four animals. We have thousands, and it's a hands-on experience. We have more than the zoo."

The expos are scheduled for the first Sunday of each month, with the first from 9 a.M. To 3 p.M. Jan. 7.

Lori Ziencik, Frazer supervisor, said she hopes the monthly show stimulates business for other mall shops.

"It's nice to see something new finally going in," Ziencik said.

Vendor Scott Hollabaugh operates a mobile educational program called Iceman Reptiles. He takes animals on the road, to events such as Ford City Community Days, to promote proper care and "open minds about reptile reputations."

"I like to advocate for the industry," he said. "Some animals get a bad rap, but in the wrong hands anything can be bad.

"It's important to me to be able to work with people and give them an experience they might not get anywhere else."

The expo boasts 100 vendors who set up shop and help to similarly educate the public.

"It's like a flea market for people that are exotic animal lovers," South said. "Vendors bring animals that they breed and produce, and the public gets to ask questions and get up close and personal."

South, originally from Monroeville, grew up with a passion for exotic animals and participated in her first show at 18 thanks to help from a family friend, the late Pittsburgh zookeeper Herb Ellerbrock.

Ellerbrock, a Sharpsburg native, founded the expo as well as the nonprofit Pittsburgh Herpetological Society, to bolster the ethical treatment of reptiles and amphibians.

He was responsible for helping to bring the first Komodo dragon — "Noname" — to the Pittsburgh Zoo & Aquarium in 1993.

South first participated in the expo in its original location at the Palace Inn in Monroeville and eventually took over when it moved to the Harmar House in the late 1990s.

Hollabaugh, who owns more than 90 snakes, lizards and tortoises, first started attending the show in 1995.

It is the longest-running reptile expo in Pittsburgh, he said.

"It offers an inviting atmosphere for adults and children," Hollabaugh said. "Over the years, we've had customers in their 70s and 80s who still keep reptiles as pets. It's a lifelong passion for some."

Moving to the mall will benefit the larger community, he said, and bring business to the restaurants and other shops.

"It's a nice location for someone to make a day out of it," Hollabaugh said.

Patrons who visit the show will see a variety of creepy crawlers and slimy salamanders, along with jumping spiders — which currently are a hot commodity, South said.

"They look like happy little creatures who do a little dance," she said.

Alligators will be on display but not for sale.

South now lives in Florida and travels to the Alle-Kiski Valley once a month for the show.

She said a priority for her is teaching conservation. The expo accepts animals that people can no longer house so they don't end up in the wild. They took in an 8.5-foot alligator in recent months.

"Our favorite part of the show is helping kids get to hold and learn about the animals," South said. "That promotes an ongoing love for these creatures."

The Pittsburgh Reptile Show & Sale is in the space formerly held by the glow-in-the-dark golf business, at the end of the mall near Dick's Sporting Goods.

The cost is $6 at the door; children 4 and younger are admitted free.

Tawnya Panizzi is a TribLive reporter. She joined the Trib in 1997. She can be reached at tpanizzi@triblive.Com.

A Herpetologist Reveals The Only National Parks With No Venomous Snakes

Latitude is the best rule of thumb for knowing where deadly snakes might be found. Here are some ... [+] national parks, mostly northerly, where the risk of a dangerous snakebite is essentially zero.

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On a recent trip to Acadia National Park in Maine, a campsite ranger was kind enough to inform me that there were no venomous snakes in the park. He didn't realize he was talking to a seasoned herpetologist who has spent a large part of his career studying snakes and reptiles (I already knew we wouldn't run into any venomous snakes in the park–in fact, there aren't any venomous snakes in the entire state of Maine). That said, I'm sure many campers appreciate the reassurance.

So, in the same spirit, I'll take this ranger's good wisdom one step further and reveal the national parks that don't have any venomous snakes.

As a general rule, the farther north you go, the less likely you are to encounter a venomous snake (or any snake, for that matter). Cold-blooded animals prefer warmer climates and snakes are no exception. So, in parks such as Saguaro National Park in Arizona or Everglades National Park in Florida, the risk of encountering a deadly snake is high. As you move away from the equator, the risk goes down.

There are more than 60 national parks in the United States. Here are 22 that have no venomous snakes.

Every National Park In Alaska (Denali, Gates Of The Arctic, Glacier Bay, Katmai, Kenai Fjords, Kobuk Valley, Lake Clark, Wrangell-St. Elias)

Denali National Park in Alaska has no venomous snakes—but it has plenty of other potentially ... [+] dangerous animals.

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Alaska lacks venomous snakes due to its cold climate. The state's northern latitude and harsh winters inhibit the survival of reptiles reliant on warmth. Furthermore, natural barriers like the Rocky Mountains and Canadian wilderness, coupled with Alaska's historical glaciation, have limited the migration and establishment of snake populations from more southern regions. These factors collectively contribute to Alaska being one of the few places in the United States devoid of venomous snakes.

Hawaiian National Parks (Hawaii Volcanoes, Haleakalā)

Despite its tropical environment, Hawaii is home to no venomous land-dwelling snakes. Pictured here ... [+] is Haleakalā National Park on the island of Maui.

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Hawaii does not have any native land-dwelling venomous snakes due primarily to its geographic isolation (although its marine waters do see the occasional venomous sea snake). As an isolated island chain in the middle of the Pacific Ocean, Hawaii never had any land connections with mainland areas where venomous snakes evolved. Nevertheless, the state's tropical climate and unique biodiversity could support the establishment of invasive snake populations (similar to the brown tree snake invasion on the Pacific island of Guam). Fortunately, strict biosecurity measures are also in place to prevent the introduction of invasive species, including venomous snakes, which could disrupt Hawaii's native flora and fauna.

Pacific Northwest National Parks (Crater Lake, Mount Rainier, Olympic)

Hikers at Crater Lake National Park in Oregon can spend more time soaking in the breathtaking views ... [+] without the worry of watching out for venomous snakes, as there are no venomous species in the park.

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While it is possible to find venomous snakes in the Pacific Northwest (the western rattlesnake is present in this region), you won't find them at Crater Lake, Mount Rainier or Olympic National Parks. North Cascades National Park is the only park in the Washington/Oregon region where you'll need to be on guard. Even there, the risk is minimal.

Great Lakes National Parks (Voyageurs and Isle Royale)

Isle Royale National Park in Michigan is home to only two species of snakes, neither of which is ... [+] venomous.

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The national parks of the Great Lakes region, including Voyageurs and Isle Royale, do not have venomous snakes primarily due to their northern latitude and cooler climate. These parks are located in the northern Midwest, where winters are harsh and temperatures remain relatively cool throughout much of the year. Such conditions are not favorable for the survival of venomous snakes, which typically require warmer climates to regulate their body temperature and maintain metabolic functions.

Southern National Parks Without Venomous Snakes (Channel Islands and Dry Tortugas)

Mainland California is home to several rattlesnake species, but the remote Channel Islands National ... [+] Park off the coast is free of venomous snakes.

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Dry Tortugas National Park and Channel Islands National Park do not have venomous snakes not due to their temperature, but primarily due to their unique island environments and geographical isolation. Dry Tortugas National Park is located about 70 miles west of Key West, Florida, in the Gulf of Mexico. The islands in this park are small and composed of coral and sand, which do not provide suitable habitat for snakes.

Similarly, Channel Islands National Park, located off the coast of southern California, consists of several isolated islands with rugged coastal terrain. The cool marine climate and isolated habitat of these islands do not support any populations of venomous snakes. However, Santa Catalina Island, a nearby island further to the south, does have an insular population of southern Pacific rattlesnakes.

Five other national parks that lack venomous snakes–for many of the reasons mentioned above–are Acadia (Maine), Glacier (Montana), Grand Teton (Wyoming), Cuyahoga Valley (Ohio), and the Great Sand Dunes (Colorado). Although the latter two parks have populations of venomous snakes nearby, which may one day be found within the boundaries of these parks.

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