Although 45 species of snakes are found in Florida, only the 6 listed here are venomous 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 venomous, 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 venomous. 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 U.S. Food and Drug Administration provides information on snakebite treatment and how to avoid being bitten by a venomous snake.

The only acceptable treatment for venomous snakebite, involves the use of antivenin. So if you or someone else is bitten by a venomous snake, seek immediate medical attention at the nearest hospital or medical facility. Stay calm, remove any rings that could restrict circulation if tissues swell, keep the bitten limb below the level of the heart, and immediately seek medical attention. Your most important aids in getting to a hospital and treatment may be car keys or a cell phone.

The snake 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.

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)

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, venomous 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

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
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.

Description: Average adult size is 36-60 inches (76-152 cm), record is 74.5 inches (189 cm). Can be a large, heavy bodied snake. The reddish brown stripe running down the center of the back is disrupted by a series of large, black, chevron-like crossbands on the pinkish gray or tan body. The tail is uniform black. The head is large and sometimes with a dark diagonal line through the eye or just behind the eye.

Range: This snake has a very limited range in our state, found in only 8 or 9 counties in north Florida. It ranges as far south as Alachua and Dixie Counties and as far west as Hamilton and Suwannee Counties. There are verbal reports that this snake occurs in a few northern counties of the panhandle, but there are no verified records.

Habitat: Timber rattlesnakes in Florida prefer low bottomlands where it is fairly damp, river beds, hammocks pine flatwoods, swamps, and cane thickets.

Comments: This snake was once very common and still is in some parts of its range. Throughout the past it, as well as other rattlesnakes, has been persecuted by in rattlesnake roundups, skin shops, and in senseless killings. The rattlesnakes and other snakes, are one of our best allies in the fight to control rodents. They should be respected, not feared.

This snake should be given a wide berth and left alone. Because of its cryptic coloration (camouflage), it can be easily overlooked, especially if it does not rattle.

Description: Average adult size is 20-30 inches (51-76 cm), record is 47.5 inches (121 cm). Body ringed with black, yellow, and red; narrow yellow rings separating the wider red and black rings. The rings continue across the belly of the snake. From tip of snout to just behind the eye the head is black. The tail is black and yellow, without any red rings. The red rings usually contain black flecks or spots. The pupil is round.
The color pattern of the young is the same as the adults.

Range: The Coral Snake occurs throughout the entire state including the northern keys. The species extends north to southeastern North Carolina and west to eastern Texas and northeastern Mexico.

Habitat: This snake occupies a variety of habitats, from dry, well-drained flatwoods and scrub areas to low, wet hammocks and the borders of swamps. They are quite secretive and are usually found under debris and in the ground, but occasionally they are found in the open, and have even been seen climbing the trunks of live oaks. Good numbers of them are turned up when pine flatwoods are bulldozed, particularly in south Florida.

Comments: Because they also are ringed with red, black, and yellow or white, two harmless snakes in Florida, the Scarlet Kingsnake and the Scarlet Snake, often are confused with the Coral Snake. Both of these mimics (look-a-likes) can be distinguished from the Coral Snake by their red snouts and red on their tails. In addition, the red bands of the Scarlet Kingsnake and the Scarlet Snake never touch the yellow bands (the red and yellow are separated by the black). Also, on both the Coral Snake and the Scarlet Kingsnake the rings go all the way around the body, but not on the Scarlet Snake which has a white belly. Both the Scarlet Kingsnake and the Scarlet Snake are beneficial and should not be harmed

If you have difficulty separating the harmless mimics from the Coral Snake, the following mnemonic rhymes will identify the Coral Snake for you: ‘If red touches yellow, it can kill a fellow,’ and ‘If its nose is black, it’s bad for jack.’
Because the Coral Snake is a relative of the cobras, people believe its bite nearly always is fatal. While its bite is serious and should receive immediate medical attention, statistics suggest that the bite of the Coral Snake is less threatening than the bite of a Diamondback Rattlesnake.
Coral Snakes feed on lizards, other snakes, and frogs