Venomous Snakes of Eastern North America 1

Venomous Snakes of Eastern North America

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Venomous snakes have always been maligned by a majority of people.  Due to this, many, unfortunately are killed on sight.  In many regions of the United States, snakes are greatly reduced in number, especially the larger venomous species.  In the Atlanta area, the canebrake rattlesnake is a great example of a snake that most likely was quite common in Cobb and Fulton Counties, however, today this species is extremely uncommon and is extirpated from most of its historic range within the Atlanta area.  Not only are snakes intentionally by people, they are also extremely vulnerable to being road casualties as habitat is so fragmented with roads being prominent features of the Atlanta landscape.   In studies, it has been found that the large rattlesnake species require very large tracts of undisturbed habitat to sustain viable populations.  Most snakes tend to be fairly sedentary but through telemetry work tracking large rattlesnakes, it has been found that males will occassionally just go on a “crawl about”.  They may move as much as a 1/2 of a mile in a very short period of time.  In addition, species like the mountain type timber rattlesnakes, will migrate to and from hibernaculums and females will congregate at sites known as nursery dens.  Through time, many of the hibernation sites and nursery dens have been destroyed, including with the use of dynamite, thus killing large numbers of rattlesnakes….which certainly have a very negative impact on the ecology of the region as the adult rattlesnakes are apex predators
and serve in the balance of nature as rodent control.

Since 1970, I have worked with an incredible number of reptile species, including venomous species.  Through this 40 years of spending a tremendous amount of time in the field, I have never had a snake, venomous or otherwise, chase me and most often, when a snake is confronted, it’s first response is to flee.  Some species, however, like copperheads and rattlesnakes, they prefer to sit tight and rely on their incredibly cryptic pattern and coloration which makes them all but impossible to see.

In regards to the venomous species of the Southeastern U.S., we certainly have a good diversity of species, all of which are illustrated below.  I have also include some of the non-venomous species that are often mistaken for venomous types.

                     Midland Water Snake:  Non-venomous

In any region of the Southeastern U.S., there are far more non-venomous species than venomous.  The reddish phase midland water snake is non-venomous.  Note the triangular shape to the head…….many non-venomous species, when threatened will flatten their head which expands their jaws giving a very triangular appearance.  Thus, a triangular shaped head is not a characteristic for only venomous species.

Left:  Copperhead, venomous.  Right:  Midland water snake 

In this photo, the midland water snake is the larger reddish snake on the right and the tan colored snake with the dark hour glass markings is a copperhead, which is venomous.

 

              Light colored Copperhead                                     Dark colored copperhead

The venomous pit-vipers of the Southeast, all have verticle pupils and they have a “heat sensing pit” that is located just forward and a little lower than the eye.  The snakes above are copperheads, which are a venomous species.

 

Left:  Eastern Hognose Snake.   Right:  Red-bellied water snake.  Both are non-venomous

When threatened, many non-venomous snakes exhibit characteristics that people often associate with dangerous venomous snakes.  The snake on the left is a dark phase Eastern hognose snake.  They are completely harmless and they are specialist feeders, almost exclusively on toads.  The snake on the right is a red-bellied water snake, which is non-venomous and when threatened, they expand their jaws exhibiting a very triangular head.  Water snakes, when cornered, are very pugnacious and bite as well as expell a very pugnant musk.

                                   

                                                                           Copperhead

The copperhead is the most common venomous snake in Eastern North America.  The cryptic pattern and coloration of the copperhead provides tremendous ability to go “un-noticed” and many more people come into close proximity with than realize.  Copperheads are not exceptionally large snakes and adults average only about 28 inches.  Large adults are 36″ (3 feet) and really big adults may be as large as 40″ .  Copperheads are venomous and when bites occurr on people or pets, medical attention is required. 

   

Left:  Litter of baby copperheads.                           Right:  Baby copperhead

Copperheads, like all North American pit-vipers, are live bearers.  Baby copperheads resemble adults in pattern and color but they exhibit a yellow-tail, which is used as a lure to entice insects, amphibians and small rodents within striking range.  The baby copperheads on the left is a litter of 10 babies born to an 18″ female.  The macro-photograph on the right is a baby copperhead with its head over its yellowish colored tail.  Even at birth, venomous snakes are capable of delivering a venomous bite on people and pets.  Their fangs and venom glands are small but even the bite from a newborn venomous snake requires medical attention and evaluation.

                    Baby Cottonmouth aka. Water Moccasin

The cottonmouth, aka water moccasin is a semi-aquatic venomous species that has a reputation for being aggressive , highly irratable and quick to strike.  This is extrmely unfortunate as although they are very dangerous snakes, the reputation is highly exagerated and the majority of cottonmouths encountered will stay coiled when found and only upon close approach does the animal slip into the water.  Water for cottonmouths as well as the non-venomous water snakes is the “safe haven” to which these snakes flee from danger.  If a person is in a boat and approaches a basking snake, often the escape route for the snake (the water) is cut off  by the boat and thus the snake, in its panic advances towards the boat.  The snake is not attacking the boat nor the people in it they are just trying to get to the water.  Cottonmouths are often very drab in color as adults but as newborns, they are extremely attractive as illustrated by the baby cottonmouth above.  Note the yellow tail, similar to the tail of young copperheads, which are closely related.  Baby cottonmouths are heavy bodied and are about 10 inches long at birth.

 

  Cottonmouth, note triangular body and characteristic gaping behavior.

In the deep south, cottonmouths tend to be fairly dark as adults.  During drought conditions, they may be found long distances from water.  The name cottonmouth comes from the whitish color of the interior of the mouth.  When confronted or threatened, cottonmouths throw their head back and open their mouth.  The sudden appearance of the white color is very noticable and serves as a warning of the snakes prescence.  The fangs are quite long and the venom glands hold a more than adequate amount of venom.  Due to this, cottonmouth bites require medical attention as soon as possible to insure a favorable outcome for the envenomated victim.  Cottonmouths are extremely different from the non-venomous water snakes but to most people, all large snakes in the water or along the waters edge…..are cottonmouths.  This includes areas where cottonmouths are not even found.  Cottonmouths typically, when in the water sit very high on the surface as their body is very boyant.  Non-venomous water snakes typically swim with their heads above the surface but most of the body is below water level.  Cottonmouths are very stout (heavy bodied) snakes and like the cottonmouth on the left, have a trinagular body shape.  Please note, do not handle venomous snakes….including dead ones.  Snakes that have recently been mortally wounded or that appear to be dead can still deliver a reflex bite which can result in envenomation.  The snake on the right, is about to shed its skin thus its eyes are bluish.  The fangs are folded into the outer edges of the roof of the mouth and are easily seen in this image.  The hole in the bottom of the mouth is the epiglottis which is an extension of the windpipe which allows snakes to feed on large food items and continueing breathing through the epiglottis.

              Adult Cottonmouth from S.E. Virginia

Cottonmouths in the extreme Northeastern portion of their range (southeasstern VA) are typically very colorful snakes, even as adults.  In this region, cottonmouths are usually yellowish with dark crossbands.  The image above of a 4′ cottonmouth was taken in Virginia Beach, VA in 1974

 

                       Carolina Pigmy Rattlesnake                                           

 

                                   Dusky Pigmy Rattlesnake

Pigmy rattlesnakes, aka ground rattlers.  The term pigmy rattlesnake is a very appropriate name for these little rattlesnakes.  Ground rattler is not appropriate as all of the 60 + species and subspecies of rattlesnakes are terrestrial and none live an arboreal life.  Pigmy rattlesnakes are usally less than 24 inches in length and although they are equipped with a rattle, it is so small that it is hardly audible when the snake is rattling.  The pigmy rattlesnakes differ from the the larger rattlesnake species as they have nine large scales on the top of their head whereas the larger rattlesnakes have numerous tiny scales covering the top of the head.  In the Southeastern U.S., the Carolina pigmy is found from the the southern edge of Albamarle sound (NC) south along the coastal plain to extreme Southeastern South Carolina.  The range of this species also  extends inland into the piedmont of Georgia and is found in all but the Northern tier of mountain counties in Georgia.  The Carolina pigmy may be pinkish, reddish or grayish in overall color with small, almost rectangular blotches on the back.   The Dusky Pigmy is found from coastal Georgia southward and including all of Florida.  In some areas, this little rattlesnake may be extremely abundant.  They are often found adjacent to wetlant areas as well as on hammocks within the Everglades.  They feed of small vertebrates and are especially fond of feeding on frogs and lizards.  The Dusky pigmy averages larger than the Carolina pigmy and occassional specimens of 28 inches are found.  Even though these snakes are small, their bites do require medical evaluation.  They are not known to be a species capable of delivering a fatal bite on humans but with any envenomation, people react differently and thus bites by this species should be attended to by a medical professional. People walking barefooted in Pigmy rattlesnake habitat are most prone to bites and gardening with barehands also results in a few bites each year.

 

Left:  Dusky Pigmy Rattlesnake    Right:  Carolina Pigmy Rattlesnake

Notethe yellowish tail on the young Dusky pigmy.  The Carolina pigmy is a very young animal exhibiting only its button and and one rattle.  The button at the tip of the rattle is present when the snake is born and a new rattle is added each time the snake sheds its skin.  Rattlesnakes, as do all snakes, shed their skin as they grow.  Growth is dependent upon how much food the snake is able to find and the length of activity.  Snakes in the deep south, especially in the coastal plain, are active for more months of the year than snakes living in more northerly latitudes and elevations.  Therefore, growth rates may be greater in the South compared to the same species that may be found further North.


              A young Carolina Pigmy Rattlesnake

Note the protection coloration of the eye, which is bi-colored with the dark facial stripe extend through the iris of the eye.

 

Timber Rattlesnake, canebrake phase.

The canebrake phase of the timber rattlesnake is a lowland variety that is found from Northern Florida up the Eastern seaboard to Southeastern Virginia.  This species is listed as endangered in S.E. Virginia and is afforded protection in that region.  The canebrake is a large species with big individuals attaining 5 feet in length and occassionaly even larger specimens are found.  They favor the borders if lowland swamps but are also found well into the Piedmont region in Georgia.  Canebrakes are incredibly cryptic and are most often overlooked by hikers and hunters as the snake lays motionless and blends in extremely well into the surrouonding leaf litter and vegetation.  If stepped on, or if hands are placed too close for the comfort of the snake, they will strike and their bites have the potential for being extremely serious and represent a medical emergency.  Canebrakes, like all rattlesnakes are live-bearers and females typically give birth in late August or early September.  The babies are minatures of the adult and they are usually about a foot long at birth.  Even at birth, the baby canebrake can deliver a venomous bite.

 

Mountain Phase, Timber Rattlesnakes.  The snakes above are 4 months of age.

The two timber rattlesnakes on the left, are similar in color but notice the animal on the far right is darker in overall coloration.  That snake will be a dark phase and possibly could be almost black as an adult.  The other snake in the left hand image will be a yellow phase as an adult.  Soon after birth, the coloration can provide a clue as to what the snake will look like as an adult.  The mountain phase is the timber rattlesnake that is found in the mountainous regions of Eastern North America.  In Georgia, the Northern tier of counties bordering North Carolina and TN, have populations of this rattlesnake.  Within these populations, there are a percentage of animals that will be dark phase which is something that does not occur in the canebrake phase.

 

Adult, yellow phase timber rattlesnake    Adult, dark phase timber rattlesnake

The timber rattlesnake is a snake with an amazing natural history.  In many regions these snakes move from summer feeding areas to communal hibernaculums, often at high elevations with southfacing rocky outcrops.  This, however, has resulted in the demise of many thousands of rattlesnakes as persons finding these dens, often resulted in the killing of all snakes that could be found and even in the dynamiting of den sites in years past.  Timber rattlesnakes also are known to have nursery dens.  Which are locations where many gravid females will congregate to give birth.  These sites are very beneficial, not only to allow young snakes to imprint on the area but also it gives researchers a chance to monitor populations and to get estimates on numbers of young being produced in a population from year to year.  It is extrmely important that timber rattlesnakes, when discovered by hikers or mountain bikers and other out door enthusiasts, that the snakes be left alone and unmolested.  The timber rattlesnake, while being a venomous species is an extremely important species and their numbers today are greatly reduced, which does have a negative impact on the environment.  Tjhese snakes belong in out wilderness areas, where we are visitors and a person can actually gain a great deal of satisfaction by just sitting and watching the behavior of one of these snakes when found.  Take advantage of the educational value of watching instead of killing the snake just because…………….

 

The head of a dark phase timber and the tail of the same snake.  Note the rattles.  There are nine rattles on this snakes tail and the terminal button has been broken off.  Rattlesnake rattles,  just through normal wear & tear,  have a tendency to brake off once they acheive 10 or so rattles.  This snake is from the mountains of Virginia where it may have been active for 5 to 6 months of the year.  Due to this, only a couple of rattles are most likely to be added to the rattle string each year.  During years with lots of food, more rattles may be added and during years with little food availability, only one rattle may be added.  Due to this, the age of a rattlesnake cannot be determined by the number of rattles on the snakes tail.

Eastern Diamondback Rattlesnake  The eastern diamondback (EDB) is truely one of the worlds most magnificent reptiles!  I have traveled the world and have observed reptiles on all 6 continents where reptiles are found and yet when given an opportunity, I would rather find a big eastern diamondback in the field than any other of the worlds serpents.  The EDB is an apex predator and large adults may reach over 6 feet in length.  The largest venomous snake in North America, the record length for an EDB is right at 8 feet.  Unfortunately, a specimen of that size has not been found in the past 50 years and today, snakes of 7 feet are extremely rare.  The EDB is found on the coastal plain from Central North Carolina down to and including all of Florida.  In Georgia, the EDB is a sandhill community resident and is often found in association with Gopher Tortoises and like the gopher tortoise, habitat destruction has greatly reduced the vital habitat where this snake is found.

The EDB is patterned in the typical diamond pattern which gives this snake its name. 

The Eastern Diamondback has a very large head and the dark facial stripe borded by two white stripes is characteristic for the species.  When rattleing, the sound which is somewhat of a whirring sound, is audible for as many as 30 feet away.  Unfortunately, some diamondbacks are quick to rattle, especially during hot weather, and they give themselves away to persons nearby.  Historically, this warning possibly would have prevented the snake from stepped on by large animals and the rattle most likely served a very usful purpose.  Today, many people go out of their way to kill a snake, especially venomous species and the rattle may be more of a detriment to the snake than of benefit.  In our large wilderness areas, these very impressive snakes should be left “unmolested” to carry out their vital role in the ecology of the sandhill communities of the Southeastern U.S.

The tongue of the EDB, like that of all snakes, is a very important organ and aids the snake in smelling its surroundings.  The heat sensing pits, located a little lower than the eye and between the eye and nostril, is an acute sensory organ that detects even minute heat signatures.  Warm blooded prey, like rats, squirrels and rabbits are easily perceived by the EDB with the use of their heat sensing pits.  These species make up much of the diet of this large rattlesnake.

Eastern Coral Snake: The Eastern Coral snake is the only member of the Elapid family found in the Southeastern U.S.  This family includes such notorious members cobras, mambas, kraits as well as the highly venomous species of Australia.  The coral snake spends much of its life under ground and even though they may be quite abundant in some areas, they are not frequently encountered by people.  Their bright colored bands of black, yellow and red are patterned such that each red band is bordered by yellow.  In our non-venomous species that mimic the coral snake in color, their patterns are such that the red is bordered by black.  Coral snakes feed mainly on other small snakes and their venom quickly kills their prey.  Coral snakes are quite slender but large adults may reach almost 4 feet in length.  Coral snakes, unlike the venomous pit-vipers, do not coil and strike.  They are very fast and typically when discovered, they only appear for a little while and then disappear very quickly even when in mowed grass.  Bites from coral snakes occur when the snakes are picked up or when stepped on by persons going barefoot.  Their bites can be life threatening and prompt medical attention is required to have a favorable outcome for victims of coral snake envenomation.

The nose of the coral snake is black from the tip of the nose to just behind the eye.  The large yellow band follows with another long black band inn the region of the neck.  Often the red bands have extensive black flecking as exhibited by the animal above.

   

Eastern Coral Snake (venomous)                The non-venomous scarlet snake

 

Roads and highways are death traps for many animals including snakes.  It is very obvious from many years of experience in finding snakes on highways that many people will alter their course in order to run over a snake…..especially large venomous species.  A great deal of research has been done and it appears that road mortality has a huge impact on populations of the larger species of rattlesnakes.  Above left is an adult canebrake rattlesnake, found dead on the road (DOR) in Bartow Co. Georgia.  The cottonmouth on the right was run over in the emergency lane of a highway in South Georgia.  An obvious roadkill that, unfortunately, was intentional by the driver of a vehicle.

Eastern Diamondbacks & rattlesnake round-ups.  These snakes, some of the many brought in during a South Georgia rattlesnake round-up, lived one day beyond the day this photo was taken.  The snakes were killed and skinned as part of the festivities of the round-up.  What is most amazing is that these events continue today and it is completely legal in Georgia to collect and kill as many Eastern Diamondbacks and Canebrakes as a person can find.  Annual round-ups provide prizes for the largest snake, the greatest number of snakes collected by one individual, the heaviest snake…….and each year many hundreds of these amazing snakes are slaughtered at these round-ups.  This practice is extremely detrimental in removing large numbers of apex predators from the sandhill environments of Georgia.  These round-ups should have been stopped years ago but it has proven to be impossible to pass any legislation in the state of Georgia that may protect venomous reptile species.