Three: eastern diamondback, timber (canebrake) and pygmy rattlesnakes.
FWC: “Only six of Florida's 44 snake species are venomous: the eastern coral snake, the southern copperhead, the cottonmouth, the eastern diamondback rattlesnake, the timber rattlesnake, and the dusky pygmy rattlesnake.” Source
“The Eastern Diamond-backed Rattlesnake is a large and impressive snake, and bites can be very dangerous to people and pets.” Florida Museum of Natural History
Size
Most adults 33 to 72 inches (about 3 to 6 feet); record 99 inches.
How to recognize it
Light-bordered dark stripe running diagonally through each eye
Tail ends in a rattle, often held above the ground
Cat-like vertical pupil and a deep heat-sensing pit between nostril and eye
Venom: “Only six of Florida's 44 snake species are venomous: the eastern coral snake, the southern copperhead, the cottonmouth, the eastern diamondback rattlesnake, the timber rattlesnake, and the dusky pygmy rattlesnake.” (FWC)
Range: Eastern Diamond-backed Rattlesnakes are found throughout Florida and in every county. They also occur on many nearshore islands including many of the Florida Keys and several islands in the Gulf of Mexico in Levy (e.g., Cedar Keys) and Franklin (e.g., Dog, St. George, and St. Vincent islands) counties.
Habitat: Eastern Diamond-backed Rattlesnakes are often found in pine flatwoods, longleaf pine and turkey oak hammocks, sand pine scrub areas, and coastal barrier islands. These habitats contain palmetto thickets and gopher tortoise burrows in which these rattlesnakes may seek refuge. This species is occasionally found in suburban neighborhoods where development encroaches into favorable habitats. (Florida Museum of Natural History)
“The Timber Rattlesnake is a large and impressive snake, and bites can be very dangerous to people and pets.” Florida Museum of Natural History
Size
Most adults 36 to 60 inches (3 to 5 feet); record 74.5 inches.
How to recognize it
Black tail ending in a rattle
Heat-sensing pit between nostril and eye
Large, thick head distinct from the neck; cat-like vertical pupil
Where in Florida
Timber Rattlesnakes have a limited range in Florida and are found in only 12 counties in northern Florida … Florida Museum of Natural History
What the sources say
Venom: “Only six of Florida's 44 snake species are venomous: the eastern coral snake, the southern copperhead, the cottonmouth, the eastern diamondback rattlesnake, the timber rattlesnake, and the dusky pygmy rattlesnake.” (FWC)
Range: Timber Rattlesnakes have a limited range in Florida and are found in only 12 counties in northern Florida. The range may extend to other nearby areas, but there are no confirmed records from other Florida counties.
Habitat: Timber Rattlesnakes in Florida prefer damp bottomlands, river beds, hardwood hammocks, pine flatwoods, swamps, fields, and cane thickets. This species is occasionally found in suburban neighborhoods where development encroaches into favorable habitats (Florida Museum of Natural History)
Venom: “Only six of Florida's 44 snake species are venomous: the eastern coral snake, the southern copperhead, the cottonmouth, the eastern diamondback rattlesnake, the timber rattlesnake, and the dusky pygmy rattlesnake.” (FWC)
Range: Dusky Pygmy Rattlesnakes are found throughout Florida and in every county. They are not known to occur in the Florida Keys, but they have been found on some barrier islands (e.g., St. Vincent in Franklin county).
Habitat: Pygmy Rattlesnakes are commonly found in habitats including lowland pine flatwoods, hydric hammocks, prairies, around lakes and ponds, and along the borders of many freshwater marshes and cypress swamps. Possibly the habitat in which Dusky Pygmy Rattlesnakes are most frequently encountered, at least in southern Florida, is along the banks of canals running through marshes and prairies. This species can be locally very abundant, and it is often found in suburban neighborhoods where development encroaches into favorable habitats. (Florida Museum of Natural History)
Timber rattlesnake has black chevron-like crossbands, a reddish stripe down the middle of the back and a black tail; Florida Museum says it is the only other rattlesnake likely to be confused with the diamondback in Florida.
Arizona Game and Fish: the western diamondback's tail has alternating black and white bands of roughly equal width, and a thin light stripe runs back and down from the rear corner of the eye to the upper lip.
Living with Snakes. Florida Fish and Wildlife Conservation Commission (FWC). archived copy, captured June 16, 2026; checked November 3, 2026.Archived copy. Quoted passages (1)
“Only six of Florida's 44 snake species are venomous: the eastern coral snake, the southern copperhead, the cottonmouth, the eastern diamondback rattlesnake, the timber rattlesnake, and the dusky pygmy rattlesnake.”
“The large and thick head is distinct from the neck and has a light bordered dark stripe running diagonally through each eye.”
“The tail ends in a rattle, which is often held above the ground.”
“The pupil is vertically elliptical, and there is a deep facial pit organ located between the nostril and the eye.”
“The Eastern Diamond-backed Rattlesnake is a large and impressive snake, and bites can be very dangerous to people and pets.”
“Most adult Eastern Diamond-backed Rattlesnakes are about 33-72 inches (84-183 cm) in total length, with a record length recorded of 99 inches (251.5 cm).”
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