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Guide to Florida’s Venomous Snakes
Although 45 species of snakes are found in Florida, only the 6 listed here are poisonous and a danger to humans. The remaining 39 species (and 41 subspecies) are harmless and should be protected for the beneficial role they play in natural ecosytems, eating insects, rodents, rabbits, and other small prey.
A word of caution is warranted here. If you find a snake and you do not know whether or not it is poisonous, the safest thing to do is leave it alone. Florida snakes are not aggressive and, unless they are cornered, most will flee when humans approach. Occasionally, you might encounter one that is reluctant to leave because it is basking in the sun to get warm. Among snakebite victims, an unacceptably high number are bitten on the hands and arms when they are handling the snake. Do not catch a snake and do not handle one unless you are sure it is not poisonous. In addition, for a short time after a snake is killed, its reflexes may continue to work. Those reflexes typically cause the body to writhe slowly for awhile, but they can cause a convulsive contraction and a bite, so you should not handle a freshly killed venomous snake.
The descriptions given below include characteristics that are relatively easy for the layman to see, though a few might require a close look at the snake, so we again caution you: Do not catch or handle a snake if you do not know whether it is venomous or harmless. To keep the descriptions short and simple, other characteristics known to herpetologists are not mentioned here.
Southern copperhead, Copperhead, Highland Moccasin, Chunkhead.
Kenneth Krysko photo.
Scientific name: Agkistrodon contortrix contortrix.
Description: Average adult size is 22-36 inches (56-91 cm), record is 53 inches (135 cm). A stout-bodied snake with broad, light brown to gray crossbands, alternating with dark brown to reddish-brown crossbands. Constrictions along the backbone give the dark bands an hourglass shape. On the sides of the body the dark bands usually have light centers, and occasionally one dark spot. Southern copperheads sometimes have an overall pinkish tint. The top of head in front of the eyes is covered with large plate-like scales. The pupil is elliptical, a catlike vertical slit.
Juvenile color is similar to that of adults, except that the tail of new born copperheads is bright sulfur yellow.
Copperhead: Left to right: Top of the head (notice the large plate-like
scales on the top of the head); underside of the head (chin and throat).
Copperhead: Left to right: Side of the head (notice the facial pit between
the eye and the nostril); front (face view) of the head.
Range: In Florida, this snake occurs only in the panhandle, primarily along the Apalachicola River and its tributaries, and then in the western tip of the panhandle. The FLMNH has specimens in its collections from Jackson, Liberty, Gadsden, Calhoun, Gulf, and Escambia counties. The range might extend to other nearby areas, but there are no confirmed Florida records from outside these counties. Outside Florida, the species ranges north to Massachusetts, and west to Texas and southeastern Nebraska.
Habitat: The preferred habitat is low, wet areas around swamps, stream beds, river bottoms, and damp ravines, but it also occurs on the hillsides above the wet areas. It also is found in suburban neighborhoods near people.
Comments: This beautiful snake is often confused with juvenile cottonmouths. If you found one in Florida outside the Apalachicola River valley or the extreme western end of the panhandle, chances are you have a young Cottonmouth and not a Copperhead. ‘Copperheads’ are often reported from south Florida, and the people who found them become quite belligerent when their mistake is pointed out. The two species are easy to distinguish because the dark bars on juvenile Cottonmouths have numerous dark spots and speckles in them, while the dark bars on the Copperhead have no dark spots or at most only one. Also the eye of the Copperhead is not obscured by the dark facial band typical of the Cottonmouth.
Hatchling copperheads hold the tail erect and wiggle the yellow tip like a caterpillar to attract prey within striking range.
Copperhead bites are extremely painful but usually are not life-threatening for healthy adults. They can be dangerous to children or older citizens in poor health. As with all poisonous snakebites, the victim should seek immediate medical care from a physician or hospital experienced in treating snakebite.
Cottonmouth, Florida Cottonmouth, Cottonmouth Moccasin, Water Moccasin, Moccasin.
Adult (left) and juvenile (right). J. Perran Ross photo
(left) and Kenneth Krysko photo (right).
Scientific name: Agkistrodon piscivorous conanti.
Description: Average adult size is 20-48 inches (51-121 cm), record is 74.5 inches (189 cm). A dark-colored, heavy-bodied snake. Juveniles are brightly colored with reddish-brown crossbands on a brown groundcolor. The dark crossbands contain many dark spots and speckles. The pattern darkens with age so adults retain only a hint of the former banding or are a uniform black. The eye is camouflaged by a broad, dark, facial stripe. The head is thick and distinctly broader than the neck, and when viewed from above, the eyes cannot be seen. The top of head in front of the eyes is covered with large plate-like scales. The pupil is vertical (catlike). There is a deep facial pit between the nostril and the eye.
Young juvenile Cottonmouths have a sulfur-colored tail.
Cottonmouth: Left to right: Top of the head (notice the large plate-like
scales on the top of the head, and that the eyes cannot be seen from
the top); underside of the head (chin and throat).
Cottonmouth: Left to right: Side of the head (notice the facial pit
between the eye and the nostril); front (face view) of the head.
Range: Found throughout Florida. The species extends north to Virginia and west to Illinois, Missouri, Oklahoma, and Texas.
Habitat: Any wetlands or waterway in the state. Cottonmouths can be found along streams, springs, rivers, lakes, ponds, marshes, swamps, sloughs, reservoirs, retention pools, canals, and roadside ditches. It occasionally wanders far from water, and has been found in bushes and trees.
Comments: Though the Cottonmouth occurs throughout the state, it is not as abundant as the many species of harmless watersnakes that occur in much the same habitat. Many Florida residents do not even realize that watersnakes exist. As a consequence, every large dark-colored snake found near water is counted, and usually killed, as a ‘Cottonmouth.’ Cottonmouths can easily be distinguished from watersnakes. If the head is viewed from above, the eyes of Cottonmouths cannot be seen while the eyes of watersnakes are visible; Cottonmouths have elliptical pupils and watersnakes have round pupils; Cottonmouths have a facial pit between the nostril and the eye, and watersnakes have none.
Some people believe Cottonmouths lie in wait on tree limbs overhanging water so they can drop into boats. These are usually cases of mistaken identity. The harmless brown watersnake often basks on tree limbs over the water, and when frightened by a rapidly approaching boat, they will escape by throwing themselves off the limb and into the water. Occasionally their flight comes too late and they fall into the boat. Cottonmouths feed on fish, frogs, mice, rats, and other small mammals.
When threatened, the Cottonmouth may respond by coiling its body and opening its mouth as though ready to bite. The exposed white interior of the mouth is what gave rise to the common name, ‘Cottonmouth.’ If not hard pressed, the Cottonmouth usually will retreat. This open mouth threat display has led to the widespread belief that Cottonmouths are aggressive snakes. In fact, they are one of the more sedate, even placid, poisonous snakes.
Cottonmouth bites can be quite dangerous. The victim should seek immediate medical care from a physician or hospital experienced in treating snakebite.
Juvenile Cottonmouths hold the tail erect and wiggle its yellow tip like a caterpillar to attract prey within striking range.
Eastern Diamondback Rattlesnake,
Diamondback
, Rattlesnake, Rattler.
Kenneth Wray photos.
Scientific name: Crotalus adamanteus
Description: Average adult size is 36-72 inches (91-183 cm), record is 96 inches (244 cm). A large, heavy-bodied snake with a row of large dark diamonds with brown centers and cream borders down its back. The ground color of the body is brownish. The tail ends in a rattle. The tail is usually a different shade, brownish or gray, and toward the end of the tail the diamonds fade out or break into bands. The large and thick head has a light bordered dark stripe running diagonally through the eye and there are vertical light stripes on the snout. The pupil is vertical (catlike) and there is a deep facial pit between the nostril and the eye.
The young are similar to the adults in color pattern. The tip of the tail of new born diamondbacks ends in a ‘button,’ which is the first segment of the future rattle.
Diamondback Rattlesnake: Left to right: Top of the head (notice, except
for the scales over the eyes, there are no large scales on the top of
the head); underside of the head (chin and throat).
Diamondback Rattlesnake: Left to right: Side of the head (notice the
facial pit between the eye and the nostril); front (face view) of the
head.
Range: Diamondbacks are found throughout the state of Florida, including several offshore islands and keys, and north along the coastal plain to southeastern North Carolina and west to southern Mississippi and eastern Louisiana.
Habitat: Diamondbacks are often found in pine flatwoods, longleaf pine and turkey oak, and sand pine scrub areas. These habitats contain palmetto thickets and gopher tortoise burrows in which the Diamondback may seek refuge. Humans have invaded many of Florida’s pine flatwoods and scrub areas which now contain farms, homes and shopping plazas. As a result, the displaced Diamondbacks may be turn up in backyards, golf courses, and even parking lots.
Comments: This is a large, impressive, and potentially dangerous snake. It can strike up to 2/3 its body length; a 6-foot (183 cm) specimen may strike 4 feet (122 cm). These factors, as well as others, make this a snake that should be left alone and not molested.
Some people wrongly believe the Diamondback must rattle before striking. This is not true. It can lie silent and motionless, and then strike without the usual nervous buzz from its rattle. In fact, Diamondbacks that rattle are more apt to be heard, seen and killed, and Diamondbacks that remain silent are more apt to go undiscovered and pass on their genes to the next generation. In this way, we inadvertently are selecting for rattlers that do not rattle.
This snake is extremely beneficial to man because it preys on rats, mice, rabbits, and other warm blooded prey, many of which are considered pests. Nevertheless, the general public in Florida feels so threatened by the Diamondback Rattlesnake that most are killed on sight. This indiscriminate killing, combined with the widespread loss of rattlesnake habitat to agricultural development and urban sprawl and commercial hunting for rattlesnake skins, has caused a decline in most Diamondback Rattlesnake populations. Though not endangered, the species clearly is in trouble.
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