Tag Archives: SNAKES

Why do snakes flick their tongues?

Kurt Schwenk is a professor of Ecology and Evolutionary Biology at the University of Connecticut. This story originally featured on The Conversation.

As dinosaurs lumbered through the humid cycad forests of ancient South America 180 million years ago, primeval lizards scurried, unnoticed, beneath their feet. Perhaps to avoid being trampled by their giant kin, some of these early lizards sought refuge underground.

Here they evolved long, slender bodies and reduced limbs to negotiate the narrow nooks and crevices beneath the surface. Without light, their vision faded, but to take its place, an especially acute sense of smell evolved.

It was during this period that these proto-snakes evolved one of their most iconic traits—a long, flicking, forked tongue. These reptiles eventually returned to the surface, but it wasn’t until the extinction of dinosaurs many millions of years later that they diversified into myriad types of modern snakes.

As an evolutionary biologist, I am fascinated by these bizarre tongues—and the role they have played in snakes’ success.

A puzzle for the ages

Snake tongues are so peculiar they have fascinated naturalists for centuries. Aristotle believed the forked tips provided snakes a “twofold pleasure” from taste—a view mirrored centuries later by French naturalist Bernard Germain de Lacépède, who suggested the twin tips could adhere more closely to “the tasty body” of the soon-to-be snack.

A 17th-century astronomer and naturalist, Giovanni Battista Hodierna, thought snakes used their tongues for “picking the dirt out of their noses … since they are always grovelling on the ground.” Others contended the tongue captured flies “with wonderful nimbleness … betwixt the forks,” or gathered air for sustenance.

One of the most persistent beliefs has been that the darting tongue is a venomous stinger, a misconception perpetuated by Shakespeare with his many references to “stinging” serpents and adders, “Whose double tongue may with mortal touch throw death upon thy … enemies.”

According to the French naturalist and early evolutionist Jean-Baptiste Lamarck, snakes’ limited vision obliged them to use their forked tongues “to feel several objects at once.” Lamarck’s belief that the tongue functioned as an organ of touch was the prevailing scientific view by the end of the 19th century.

Smelling with tongues

Clues to the true significance of snake tongues began to emerge in the early 1900s when scientists turned their attention to two bulblike organs located just above the snake’s palate, below its nose. Known as Jacobson’s, or vomeronasal, organs, each opens to the mouth through a tiny hole in the palate. Vomeronasal organs are found in a variety of land animals, including mammals, but not in most primates, so humans don’t experience whatever sensation they provide.

A diagram showing the location of the vomeronasal organ on a snake
Tongue tips deliver odor molecules to the vomeronasal organ. Illustration: Kurt Schwenk, CC BY-ND

Scientists found that vomeronasal organs are, in fact, an offshoot of the nose, lined with similar sensory cells that send impulses to the same part of the brain as the nose, and discovered that tiny particles picked up by the tongue tips ended up inside the vomeronasal organ. These breakthroughs led to the realization that snakes use their tongues to collect and transport molecules to their vomeronasal organs—not to taste them, but to smell them.

In 1994, I used film and photo evidence to show that when snakes sample chemicals on the ground, they separate their tongues tips far apart just as they touch the ground. This action allows them to sample odor molecules from two widely separated points simultaneously.

Each tip delivers to its own vomeronasal organ separately, allowing the snake’s brain to assess instantly which side has the stronger smell. Snakes have two tongue tips for the same reason you have two ears—it provides them with directional or “stereo” smell with every flick—a skill that turns out to be extremely useful when following scent trails left by potential prey or mates.

Fork-tongued lizards, the legged cousins of snakes, do something very similar. But snakes take it one step farther.

Swirls of odor

Unlike lizards, when snakes collect odor molecules in the air to smell, they oscillate their forked tongues up and down in a blur of rapid motion. To visualize how this affects air movement, graduate student Bill Ryerson and I used a laser focused into a thin sheet of light to illuminate tiny particles suspended in the air.

A snake flicking its toungue through a veil of smoke creating two swirls
Tongue-flicking creates small eddies in the air, condensing the molecules floating within it. Photo: Kurt Schwenk, CC BY-ND

We discovered that the flickering snake tongue generates two pairs of small, swirling masses of air, or vortices, that act like tiny fans, pulling odors in from each side and jetting them directly into the path of each tongue tip.

Since odor molecules in the air are few and far between, we believe snakes’ unique form of tongue-flicking serves to concentrate the molecules and accelerate their collection onto the tongue tips. Preliminary data also suggests that the airflow on each side remains separate enough for snakes to benefit from the same “stereo” smell they get from odors on the ground.

Owing to history, genetics and other factors, natural selection often falls short in creating optimally designed animal parts. But when it comes to the snake tongue, evolution seems to have hit one out of the park. I doubt any engineer could do better.

The Conversation

Author: Purbita Saha
This post originally appeared on Science – Popular Science

SNAKES! Texas' venomous rattlers, cottonmouths slithering out with warmer weather

AUSTIN (KXAN) — As summer months draw near and temperatures rise, so do the odds of snakes coming out to hiss — or deliver a dangerous kiss!

While snakes serve valuable functions to their habitats (more on that below), it’s important to know what to look out for – for their safety and yours.

Many types of venomous snakes call Texas home: here’s how to spot them and what to do if you find yourself on the receiving end of a nasty bite.

Lone Star Snakes

Rattlesnakes

These serpents are among the most common found in Texas, according to Texas Parks and Wildlife. There are 10 species found in the state — including the Western diamondback, the most common venomous snake in all of Texas.

You can spot a Western diamondback by the brown, diamond-shaped marks down its back and white and black rings near the tail. They can reach up to seven feet, TPW says.

A Western diamondback rattlesnake (iStock/Getty Images Plus)

Other rattlers include the Timber rattlesnake, Mottled Rock rattlesnake, Banded Rock rattlesnake, Blacktail rattlesnake — many are found in the western parts of Texas.

This July 2019 photo by Charlton McDaniel of Fort Smith, Ark., shows a copperhead snake eating a cicada in Ozark National Forest (Charlton McDaniel via AP)

Copperheads

Copperheads can be found all across Texas, with three subspecies claiming different territories for themselves.

The Southern copperhead can grow up to 20-30 inches long and is found in the eastern one-third of Texas. The Trans-Pecos copperhead is about the same size and can be found in the area of its namesake. Meanwhile, the Broadbanded copperhead can be found in central and western Texas and can be up to two feet long! No internet connectivity, despite its name.

Cottonmouths

These are also commonly known as “water moccasins.”

These can be various shades of brown, green and even black. You can spot them by distinct colored bands across their bodies. There’s only one recognized subspecies found in Texas: the Western cottonmouth. This snake, TPW says, is the world’s only semi-aquatic viper, which is a family of snake species.

The cottonmouth’s name comes from the white tissue that can be seen inside its mouth, which can be seen when it’s threatened.

A water moccasin climbs from a roadway onto the Mississippi River Levee in the English Turn section of New Orleans, in October 2015 (AP Photo/Gerald Herbert)

Cottonmouths can be up to 3 1/2 feet in length and found in eastern Texas swamps, waterways, marshes and other bodies of water.

Coral snake

Texas Parks and Wildlife says these are the only snake in the state that’s brightly colored: red, yellow and black rings encircle its body. Venomous Coral snakes are dangerous for several reasons: including that they look similar to other non-poisonous snakes.

But there are ways to tell the difference — an old rhyme you may remember: “Red next to black-friend of Jack; red next to yellow will kill a fellow.”

Rings on non-venomous snakes, like Texas scarlet snakes, also stop near the upper body.

Coral Snake Found_462348
A photo by biologist Mark Bailey from June 2009 shows a coral snake seen in central Alabama (AP Photo/via Conservation Southeast, Mark Bailey)

Coral snakes are generally not aggressive but can deliver a serious bite if threatened. They tend to eat other snakes and reptiles.

Snakes in Your Home

No one likes uninvited house guests. The Austin Animal Center has previously reported fielding large numbers of calls of snakes being found in area homes during warmer temperatures.

A few tips the center offers:

  • Keep lawns trimmed. Snakes love hiding in tall grass and brush piles.
  • Keep rodents away. While snakes are great mouse and rat catchers, you also likely don’t want snakes in your home, either. Keeping your home rodent-free will decrease the likelihood a slithery friend may come searching for a snack.
  • Keep competition. Austin Animal Center says snakes are competitive and don’t like to share food between venomous and non-venomous types. Keeping a non-venomous rat snake around the house could deter a rattler or a copperhead from taking over.

Bites

If you happen to get bitten, Dr. Jeremy Kenter, with Ally Medical Emergency Rom in Bastrop recommends acting as soon as possible.

“The most important thing to do if you are bit by a rattlesnake is really get to your closest ER. Rattlesnake bites are extremely dangerous,” said Kenter. “One thing you should do if you are bit is call ahead to make sure they do have the antivenom.”

Wanting to treat your bite immediately may also tempt you to try a home remedy you may have heard, like sucking out the venom. But St. David’s Round Rock nurse Kristen Hullum says not so fast.

There are some cowboy movies suggesting to suck the venom out,” said Hullum. “You don’t want to do that.”

Texas Parks and Wildlife also recommends keeping victims — or yourself — calm, while keeping the bitten arm or leg below heart level. Next, clean the bite with soap and water. Remove tight-fitting clothes and jewelry since swelling may occur.

If possible, you should try to identify the snake that bit you, but if it will take too much time, you should call 911 immediately.

Snakes are useful

While many of us share a common fear of snakes — also called Ophidiophobia — they creatures don’t prey on humans and generally like to avoid us altogether. Most snake bites are the result of humans being reckless or threatening to snakes, TPW says.

Snakes have historically been maligned, write University of Illinois’ Wildlife Epidemiology Laboratory students Katie V. and Kennymac, in their article, “Why YOU Should Care about Snakes.”

Snakes have been the victim of many unprovoked attacks and killings, but it’s important for humans to know how much good the animals provide to their habitats. One big help snakes offer is by controlling pest populations — and controlling the harmful diseases they can carry.

The Circle of Life: while snakes are predators, they’re also prey for other animals. This, according to the Wildlife Epidemiology Lab, is what’s called being a “mesopredator.” Larger predators like foxes, birds of prey, and bigger snakes are quick to snatch up a smaller snake.

Overall, snakes serve critical roles in sustaining Earth’s ecosystems. So keep your distance and let snakes do their work!

Author: Russell Falcon
This post originally appeared on KXAN Austin