One of the most memorable reptile sightings while hiking in Tennessee was this Timber Rattler sunning itself on a ledge overlooking the canyon. Fantastic! I was hiking with my dog Sky that day – fortunately she didn’t get too curious.

NOTE: I must apologize for the quality of the first couple of Timber Rattlesnake photos – low-resolution scans from my film camera days. I captured the top two photos on the wonderful Fiery Gizzard trail near Monteagle, Tennessee; the other pictures – also Timber Rattlesnakes unless otherwise noted – are public domain images (as far as I could tell).

The well-represented Crotalinae subfamily of snakes, or crotaline snakes, is comprised of the pit vipers: snakes that possess an additional tool consisting of a heat-sensing pit organ located between the eye and the nostril on either side of the head, allowing them to hone in on warm-blooded prey like mice and rats.

Herpetology experiments have shown that pit vipers can strike accurately at moving objects that are less than 0.2°C warmer than the background – even when deprived of their senses of sight and smell. It’s almost as if the pit organs work like a primitive pair of eyes; however, no one knows for certain (yet) whether these snakes experience this “sixth sense” visually or in some other manner. In any case, the pit organs are of immense value to predators operating at night.

Poisonous snakes in Tennessee

According to the Tennessee Amphibians and Reptiles website, Tennessee is home to 138 species of snakes, turtles, lizards, salamanders, and frogs. Of these, over forty species are snakes, and only four (4) of these are poisonous pit vipers. Topping this short list as the coolest and most beautifully patterned venomous snake in Tennessee is the Timber Rattlesnake, which can be found all over the state in now dwindling numbers.

The other poisonous snakes found in Tennessee include cottonmouths, copperheads, and pygmy rattlers. The cottonmouth or water moccasin (generally the Western Cottonmouth) is found in wet areas, mostly in the western half of Tennessee. There are two copperhead subspecies in Tennessee: the Southern Copperhead lives predominantly in the southwestern section of Tennessee and the Northern Copperhead throughout the rest of the state. The diminutive Pygmy Rattler lives primarily in the counties along Kentucky Lake.

Kill! Kill! Kill! No, don’t.

As a major reptile fan I’ve always been both amused and disturbed by an all-too-common reaction many humans have to being surprised by a snake – especially when it occurs near a creek, river, pond, or lake. “It’s poisonous! I know it’s poisonous – my grandfather taught me when I was a kid, yada yada yada. Kill it!” To these people, all snakes are poisonous and a threat: a clear and present viper. In truth, the vast majority of snakes anyone sees in the wild – including in and around bodies of water – are harmless.

If a snake is near water…

I mentioned water for a couple of reasons: First, a faulty assumption is made by the intrepid snake hater that any serpent near water is a Water Moccasin – a Cottonmouth. Reality check: water snakes are some of the most common types of snakes remaining in Tennessee; most of the time a snake is found in or near a creek or pond, it is one of the water snakes.

Second, a great many water snakes (e.g., the very common Northern Water Snake) have a really nasty temper and will frequently change its appearance when frightened or threatened. These snakes can instantly change their body shape from cylindrical to flattened, while the head of the snake becomes almost triangular. Why? Water snakes do this in order to mimic poisonous snakes and thus appear more threatening.

Harmless water snakes of the genus Nerodia are often mistaken for Water Moccasins. These Colubrid snakes, like Water Moccasins, are semi-aquatic, thick-bodied snakes with large heads that adopt a rather aggressive demeanor when they feel threatened, but they behave differently. For example, water snakes usually flee quickly into the water, while a Water Moccasin will more often stand its ground with its threat display. Also, water snakes do not vibrate their tails when excited.

While this water snake ploy probably works wonders with most animals (except for raccoons and others who enjoy dining on snakes), the bluff has caused almost everyone to adopt and believe critical misinformation about these incredible legless reptiles. Undoubtedly, thousands upon thousands of water snakes have been mistaken for Water Moccasins or Copperheads and killed, in Tennessee alone — often because of their little trick to mimic the appearance of a snake that actually can be dangerous under certain circumstances.

There’s another highly popular but ridiculous old wives tale: Cottonmouths (aka Water Moccasins, Swamp Moccasins) are so aggressive and mean they will chase you. In reality, these snakes are more frightened of you than you are of them. They will get away if they think they can, and if not, they will stand their ground and perform a scary ritual designed to make you flee; however, Cottonmouths do not typically engage you in a chase as you run.

See what I mean about water snakes looking like copperheads to the untrained eye? The banded Northern Water Snake not only pretends to be poisonous when frightened, the bands often cause this species to be mistaken for the poisonous Copperhead. It’s a double whammy against the Northern Water Snake in terms of its already severely limited appeal to most humans.

Sad status of the Timber Rattlesnake in Tennessee

I suspect very few of you will join me in mourning the fact that the Timber Rattlesnake is now threatened in Tennessee. The cause is very predictable: the Timber Rattler is losing its home to development. Each year the habitat of the Timber Rattler shrinks in Tennessee from the year before.

The truth is, no one should be happy or relieved about this. Like all other species of animal, plant, insect, fungi, fish, and what have you, the velvety, often colorful Timber Rattlesnake has a specific role to play in our ecosystem – a role that cannot be played by any substitute (me for him, coke for gin…). Like it or not, the Timber Rattler is part of the web of life. When it disappears, there will necessarily be an effect; after all, no creature – no matter how ugly, mean, or poisonous – lives in a vacuum.

Fortunately – yep, I’m glad – it’s illegal in Tennessee to kill, harm, or hold any native wild snake against its will without a permit!

Snakebite Statistics for the United States

Here are a few interesting U.S. snakebite statistics, according to the Tennessee Wildlife Resources Agency (TWRA):

Around 50,000 people are bitten by snakes in the United States each year. While that figure may sound alarmingly high, keep in mind that it includes ALL reported snakebites. As an amateur herpetologist and unpaid naturalist from the age of five, I’ve been bitten by non-venomous snakes dozens of times and I’ve never even thought about reporting it (and I never had a bad reaction even when all those small but sharp teeth made me bleed. Considering all the other reptile aficionados out there, the 50,000 number is very, very low. The actual number of Americans being bitten by snakes each year is perhaps in the hundreds of thousands.

Of the reported fifty thousand snakebites in America, only 8,000 were bites from poisonous snakes. Of those bites from poisonous snakes, 1,200 did not even seek medical attention yet recovered fully.

Bites from non-poisonous snakes

It is true – but highly unlikely – that a medical situation could result from the bite of a non-poisonous snake. This is due mainly to the possibility of infection or allergic reaction. But think about it: it’s not that there’s anything worse about a non-poisonous snake than other creatures; after all, a bite from another human could be far more dangerous. The bite from almost any reptile or mammal could pose a danger if it breaks the skin; mouths and teeth naturally harbor bacteria in most animals, and it can enter the bloodstream when a bite draws blood.

Bites from venomous snakes

Actual deaths from venomous snake bites are very, very low in this country. You are about eight (8) times more likely to be struck by lightning than die from a snake bite, and you are twice as likely to die from wasp or bee stings as from being bitten by a venomous serpent! Only 6 to 15 people die from poisonous snake bites each year in the United States, and of those few individuals, less than half die as a result of being bitten by the kinds of poisonous snakes we have here in Tennessee (we have only four kinds of poisonous snakes here). Finally, in Tennessee there have been only seven (7) recorded deaths from snake bites during the last 40 years. There’s little to worry about.

As I conducted research for this post, I noticed that Wikipedia even has list of people who have died from being bitten by venomous snakes!

Quick ways to tell if a snake is poisonous

Unless one is familiar with snakes, it is difficult or impossible to determine for certain whether a snake is poisonous without getting too close. Even so, here are some general guidelines.

Poisonous snakes in Tennessee:

1. Are thick, heavy-set, with comparably fat bodies
2. Are all pit vipers and thus possess the pit organ on the front of their heads
3. Have elliptical pupils; non-venomous snakes have round pupils
4. Have triangular heads that are more distinct from the body than the heads of most non-poisonous snakes in Tennessee; but, as discussed above, some water snakes and hognose snakes can mimic this appearance when they want to
5. Have thick, somewhat flattened bodies – a feature that is enhanced when the snake is bothered; however, some water snakes and hognose snakes can mimic this, too (most harmless snakes have a rounder, more circular cross-section than the poisonous snakes in this state)

Binomial nomenclature of the Timber Rattlesnake

Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Reptilia
Order: Squamata
Suborder: Serpentes
Family: Viperidae
Subfamily: Crotalinae

Resources: Timber Rattlesnakes in Tennessee

• Timber Rattlesnake fact sheet
• Timber Rattlesnake
• Timber Criteria – how to tell if you really saw a Timber Rattlesnake – this is a great snake web page with many fantastic pictures
• Timber Rattler threatened in Tennessee: habitat decreasing
• Killer collection of Timber Rattlesnake and other high quality snake photos
• Timber Rattlesnake along the Connecticut River
• Timber Rattlesnake – MP3 of the snake rattling
• Timber Rattlesnake – Tennessee Aquarium
• Timber Rattlesnake – Encyclopedia of Life

Resources: Pit vipers

• Pit vipers – wiki
• Crotalus by common name
• List of Crotaline species and subspecies – wiki
• Crotalus by taxonomic synonyms
• Northern Copperhead – wiki
• Water Moccasin – wiki
• Types of Water Moccasins – eHow
• Western Cottonmouth – wiki
• A closer look at how pit vipers see heat (try to ignore the religious fundamentalist dogma)
• Pygmy Rattlesnakes – colorful little critters

Resources: Tennessee snakes, related links

• Tennessee Herpetological Society
• Snakes of Tennessee
• Venomous Snakes of Tennessee – Tennessee Poison Center
• Snakes of Tennessee: Venomous or Not?
• Tennessee Amphibians and Reptiles
• Tennessee Snake Information – Reelfoot Outdoors
• Tennessee’s snakes mostly not a problem – article in the Commercial Appeal of Memphis
• Tennessee Wildlife Resources Agency

Resources: Snake bite

• Snakebite – wiki
• Medical information about snakebite