by Rick O'Connor | Feb 23, 2026
This species is the one that causes the most concern for folks and enhances their fear of all snakes. The eastern diamondback rattlesnake (EDB) (Crotalus adamanteus) is the largest venomous snake in the U.S. Most today will only reach a length 5 feet but there are records of this snake reaching 8 feet. They can weigh up to 25 pounds, their head can be the size of a man’s fist, rattles can be the size of a human index finger, and they can carry over 1000 milligrams (mg) of venom, injecting as much as 300 mg in a single bite. Though there are venomous snakes in the U.S. with a more potent venom, because of its size and the amount of venom they can inject, EDBs are considered by many to be the deadliest snake in our country.
Eastern Diamondback Rattlesnake swimming across the Intracoastal Waterway near Pensacola Beach.
Photo: Andy Barnes
They will lie quiet for long periods of time hoping prey approaches. However, they are quick to respond to potential threats with their heart stopping rattle, can be heard from 20-30 feet away. Their strike range is longer than most native snakes – reaching 2/3 of their body length (over 3 feet for a 5-foot snake) – and are considered very dangerous. The venom is a cocktail of hemotoxins, and neurotoxins and bites left untreated can result in death in less than 24 hours. All that said – only about 1-2 people die each year from this snake. Statistics show that most are bites on the hands of men. Most were intentionally interacting with the snake. 95% were either trying to catch or kill them.
EDBs only exist in the lower coastal plains of the southeastern U.S. They are found throughout Florida and are the only rattlesnake I am aware of that lives on our barrier islands. They prefer high dry ground in pine flatwoods, scrub, pine forest, sand hills, around wetlands, grassy forest edges, palmettos, and are usually near water. They need burrows to avoid heat and cold and are often found in gopher tortoise burrows and holes around tree stumps. They are good swimmers and have no problem crossing salt water to reach our barrier islands.
They are primarily diurnal in activity but will aestivate in holes, burrows, and dens during the hot months of summer. Adults feed primarily on rabbits but will take rodents when available. The young focus on smaller rodents but could take birds, or other small mammals. Though full grown rattlesnakes have few predators, they are not considered an apex predator. Numerous creatures feed on the young and subadults, such as – alligators, feral hogs, bobcats, hawks, eagles, owls, wading birds, snake eating snakes (such as black racers, cottonmouths, king snakes, and indigos). King snakes are immune to their venom. Deer may trample a rattling young snake, but the #1 predator are humans – and not for food.
Breeding occurs in the spring with birth coming in late summer/early fall. Most snakes lay eggs but rattlesnakes, and other vipers like cottonmouths, keep the eggs within the mother giving live birth. EDBs can give birth to as many as a dozen offspring. Young rattlesnakes may not yet have a rattle, but they do have venom, and it is just as toxic as the adults.
EDB populations have declined across their range – they may no longer exist in the state of Louisiana. The cause of decline is most certainly humans. Development of habitats into farms and neighborhoods force EDBs into new territories where competition impacts the population, or into human landscapes where they will surely be killed. There are still folks who go into their natural habitats to kill or collect them for local events. They are a species of concern in most states, including Florida.
by Rick O'Connor | Feb 13, 2026
Rattlesnakes are only found in the new world. Species exist in North, South, and Central America. In the U.S. and Canada there are 30 known species. Most prefer high dry habitats, but many can be found on high ridges near, or within wetlands, and we know some will live on our barrier islands. In such habitats, if their prey is available (usually rodents), rattlesnakes can be found.
Eastern Diamondback Rattlesnake coiled beneath a live oak tree in Gulf Islands National Seashore.
Photo: Rick O’Connor
Species richness across North America includes 18 species and additional 20 subspecies.
The highest richness is found in the American southwest. The state of Arizona leads the way with 14 species and subspecies. There are five that are only found in this state, and it is the mascot of their major league baseball team. California and Texas follow with 9 species and subspecies. New Mexico is a close third with 8 species and subspecies. California and New Mexico both have one rattlesnake unique to their states.
From the southwest, rattlesnakes’ richness spread to the southeast and Midwest. Another group moved up the Rockies and the Pacific northwest. Species richness begins to decline in these areas, and even more so in New England and the Mississippi Valley. The timber rattlesnake has the largest range being found in 28 states across the country. Below are the number of species and subspecies by states.
| Number of Species and Subspecies |
States |
| 14 |
Arizona |
| 9 |
California, Texas |
| 8 |
New Mexico |
| 4 |
Georgia, Alabama, Kansas, Nevada, Utah |
| 3 |
North Carolina, South Carolina, Florida, Mississippi, Louisiana, Arkansas, Missouri, Idaho |
| 2 |
New York, Pennsylvania, Tennessee, Ohio, Indiana, Illinois, Nebraska, Oregon, Colorado |
| 1 |
Vermont, Massachusetts, Connecticut, New Jersey, Maryland, Virginia, West Virginia, Kentucky, Montana, Washington, Minnesota, North Dakota, South Dakota, Wyoming, Wisconsin, Michigan |
Depending on the state, the number found in the southeast is 3-4 species and subspecies. The coastal states have barrier islands and there is at least one species found there – the Eastern Diamondback Rattlesnake.
In the classic text published by Ray and Patricia Ashton in 1981, eight species of Florida snakes have been reported from coastal dune habitats. Another six species from salt marshes – which are found on many of these barrier islands. Based on the Ashton’s publication below is a breakdown of the species and where they can be found in the state.
| Species |
Habitat |
Status in those habitats (1981) |
Location |
Notes |
| Everglades Rat Snake |
Coastal dunes |
Uncommon |
SW – SE FL but not the Keys |
This subspecies categorization was questionable |
| Eastern Coachwhip |
Coastal dunes |
Uncommon |
Statewide |
I have seen plenty of these on our local islands |
| Crowned Snake |
Coastal dunes |
Uncommon |
North and central Florida |
The coastal subspecies is found in the Indian River area |
| Southern Hognose |
Coastal dunes |
Rare |
North and Central Florida |
At this point this snake is rare everywhere |
| Florida Pine Snake |
Coastal dunes |
Rare |
Statewide except the Everglades and Keys |
This snake is also now rare across the state |
| Brown chin racer |
Coastal dunes |
Uncommon |
Apalachicola Bay – St. Joe Bay area |
|
| Everglades racer |
Coastal dunes |
Rare |
SW-SE FL |
|
| Eastern Diamondback Rattlesnake |
Coastal dunes and Salt marsh |
Rare in dunes
Uncommon in marsh |
Statewide |
I have not encountered this snake in salt marshes but have in coastal dunes |
| Cottonmouth |
Salt marsh |
Rare |
Statewide |
This snake is becoming more common on barrier islands. I would consider it common |
| Florida Kingsnake |
Salt marsh |
Uncommon |
Peninsula Florida |
|
| Blue Striped Ribbon Snake |
Salt marsh |
Uncommon |
Big Bend |
|
| Atlantic Salt Marsh Snake |
Salt marsh |
Rare |
Indian River region |
This snake is now listed |
| Gulf Salt Marsh Snake |
Salt marsh |
Uncommon |
Panhandle and Big Bend |
I have found these in the bay area, not on the island. But would expect them there |
| Mangrove Salt Marsh Snake |
Salt Marsh |
Uncommon |
Hernando County south – the Keys – north to Palm Beach |
|
Based on the Ashton’s publication – the only rattlesnake found in either habitat would be the Eastern Diamondback Rattlesnake. The Dusky Pygmy Rattlesnake has been found statewide but there no records on barrier islands – though it has been reported just across the Intracoastal Waterway from our islands and could very well be there. The Timber rattlesnake has only been reported from upland habitats in north Florida.
So, based on this, our next article will focus on the one rattlesnake known to be on our islands – the Eastern Diamondback.
References
Rubio, M. 2010. Rattlesnakes of the United States and Canada. ECO Herpetological Publishing & Distribution. Rodeo, New Mexico. pp. 307.
Gibbons, W., Dorcas, M. 2005. Snakes of the Southeast. The University of Georgia Press. Athens, Georgia. pp. 253.
Graham, S.P. 2018. American Snakes. John’s Hopkins University Press. Baltimore, Maryland. pp. 293.
Ashton, R.E., Ashton, P.S. 1981. Handbook of Reptiles and Amphibians of Florida; Part 1 – The Snakes. Windward Publishing. Miami, Florida. pp. 176.
by Rick O'Connor | Feb 3, 2026
The purpose of consuming food is to acquire energy. It does not make sense to expend more energy to kill your prey than you will receive from consuming it; there would be a net loss. Therefore, as we mentioned in Part 2, predators select prey that are easy to kill and require little energy.
Eastern diamondback rattlesnake swimming in intracoastal waterway near Ft. McRee in Pensacola.
Photo: Sue Saffron
The problem for snakes is that they lack forearms and claws for doing this; they have only their teeth – and then to hold on with dear life so as not to lose it. A second problem for the rattlesnakes is that their feeding seasons are short due to hibernation, aestivation, and for some females – gestation. With a shorter feeding season, they need to feed on something with a lot of energy to hold them during non-feeding periods. This means feeding on endotherms – and the larger the better. This of course means going after prey that might be difficult to subdue, thus breaking the general rule. Answer to this problem… venom.
With venom rattlesnakes do not have to expend a lot of energy. The energy costs are within the lightning quick strike and in the production of the venom itself. As my professor said when I was in school – “venom is expensive for snakes”. This is why many venomous snakes will give a dry or bluff bite when dealing with potential predators. It is best to save the venom for what it was intended for. So, with venom, they can quickly strike a larger, energy rich, rabbit for a meal. And they do like rabbits.
Young rattlesnakes will consume what they can, adults prefer mammals. Rattlesnakes are good swimmers and are known to take both frogs and salamanders while swimming, but they do not prey on fish. Their menu also includes a variety of rodents, rabbits, shrews, moles, bats, lizards, toads, birds, bird eggs, centipedes, scorpions, crickets, and other insects.
Though many consider rattlesnakes apex predators, they are not. There are many species that feed on them, albeit mostly the smaller rattlesnakes within the population. By far their number one problem is humans. Based on the natural history of these snakes we have discussed in previous articles; you can understand their problem with us. They settle down in a selected hibernaculum for hibernation, aestivation, or gestation, only to have the habitat disturbed or destroyed by heavy equipment clearing land for new homes, roads, or shopping centers. These disturbed snakes now must move, which places them within view of humans, and we know what happens then. There is also the habitat fragmentation problem. Where roads, and other developments, cut through their range forcing them to again to move through our neighborhoods while trying to find prey, hibernacula, or females if breeding season. You can understand they really do not want to be around us but often have no choice.
With more natural predators, no species targets rattlesnakes but rather takes them when the opportunity presents itself. Their predators include opossums, armadillos, badgers, skunks, ring-tails, fox, coyotes, feral hogs, feral dogs, feral cats, bobcats, panthers, javelinas, hawks, eagles, owls, osprey, kites, falcons, shrikes, ravens, crows, road runners, turkeys, king snakes, racers, whip snakes, indigo snakes, cottonmouths, alligators, snapping turtles, and – at times – other rattlesnakes. Keep in mind, these will take on smaller rattlesnakes, larger adults have few predators.
As we mentioned in Part 3, typically only one out of 12 newborn rattlesnakes will reach the age of three. Those who reach full growth (up to eight feet with it the eastern diamondback) may live to be 25 years old. But we have also mentioned that very few rattlesnakes reach full growth these days. This and their habit of not breeding every year has placed many populations in peril.
In Part 7 we will look at the habitat and range of rattlesnakes across our country.
References
Rubio, M. 2010. Rattlesnakes of the United States and Canada. ECO Herpetological Publishing & Distribution. Rodeo, New Mexico. pp. 307.
Gibbons, W., Dorcas, M. 2005. Snakes of the Southeast. The University of Georgia Press. Athens, Georgia. pp. 253.
Graham, S.P. 2018. American Snakes. John’s Hopkins University Press. Baltimore, Maryland. pp. 293.
by Rick O'Connor | Jan 12, 2026
Breeding is a major part of all animal life cycles, and this is no different for rattlesnakes. Like other reptiles there are separate sexes, and internal fertilization is the rule. For this to happen, during breeding season males must find the females and often must compete with other males for the right to breed.
Diamondback rattlesnake near condominium construction site Pensacola Beach.
Photo: Sawyer Asmar
Breeding typically occurs in the spring shortly after emerging from hibernation. The females are hungry from hibernating, but they must gain fat to help feed the developing young. In reptiles’ embryonic development usually occurs within an egg. Within this egg the developing embryo is connected to a yolk sac from which they feed. There is another attached sac called the allantois which is where they go to the bathroom. When the yolk sac is gone and the allantois is full, it is time to hatch. It is the mother’s job to produce this egg and place it somewhere where it will remain warm and protected. But here the rattlesnakes are a bit different.
They differ in that though they produce eggs, they do not lay them in a nest. Rather she keeps the eggs within her body for warmth and protection. The covering of their eggs is more of a membrane rather than a shell. During this gestation period, the females will find a hiding place where she can still access sunlight. She will position herself so that her body remains warm for her offspring and then lie for 2-3 months until they are born. Though she may drink, she usually does not eat during the period.
The mother typically produces about dozen such eggs and they emerge in early fall. The young are venomous and innately understand how to survive. However, the mother often stays with them until they shed their first skin, at which time she will leave them on their own. She will then binge feed preparing for the upcoming hibernation period.
Some females will breed again in the fall. These will store the sperm during hibernation and fertilize their eggs in the spring. During both the spring and fall breeding periods the males will venture far and wide to find females. It is during these periods when many come into contact with people in strange places. The drive to find females will have them move into neighborhoods and human habitats that they would otherwise avoid.
Rattlesnakes live around 25 years. They become sexually mature in 6-7 years but do not breed every year. It has been estimated that only one of the 12 or so newborns will make it to the age of three. With the infrequent breeding of adults and low success rate of the offspring, rattlesnakes are susceptible to population declines when adults are removed. The loss of habitat, road kills, decline in prey, natural predation, and indiscriminate killing by human’s rattlesnake populations can suffer, and many are considered species of concern.
Next, we will look at predator/prey interactions with rattlesnakes.
References
Rubio, M. 2010. Rattlesnakes of the United States and Canada. ECO Herpetological Publishing & Distribution. Rodeo, New Mexico. pp. 307.
Gibbons, W., Dorcas, M. 2005. Snakes of the Southeast. The University of Georgia Press. Athens, Georgia. pp. 253.
Graham, S.P. 2018. American Snakes. John’s Hopkins University Press. Baltimore, Maryland. pp. 293.
by Rick O'Connor | Dec 29, 2025
All animals have a thermal range within which they can survive. For some it is very small range, for others it is amazingly large. Whatever their range is, they function best near the upper portion of it. “Warm blooded” animals (endotherms) have high metabolisms and generate warmth internally. Most have covering over their skin, fur or feathers, that assist with insulating them. “Cold blooded” animals (ectotherms) are the opposite. They have lower metabolisms, generate less internal heat, and most have covering over their skin (scales) that do not provide sufficient insulation. Thus, ectotherms must bask in the sun to get their body temperatures up to peak functioning levels. They will also hide in the shade or water to cool down. Rattlesnakes are ectotherms.
Eastern diamondback rattlesnake crawling near Ft. Pickens Campground.
Photo: Shelley Johnson
Generally, the coldest part of the day is just before dawn. If a snake was hunting at night, and many species do, they will venture out in the morning to find a sunny spot to warm up so they can complete the digestive process. They do need sun, but they need to avoid open spaces where predators can find them. Often, they will select spots near the edge of a wooded area, or edge of rocky outcrop, so they can dash in if trouble arrives. Snakes have been known to stretch out on roads where the pavement has been heated during the day. Unfortunately, many are hit by vehicles while doing this. As the day warms up, they will move into cooler spaces to avoid overheating. Rattlesnakes are more active, and prefer to hunt during the daylight hours, though evening movements do occur.
There are seasonal behavior changes to deal with thermoregulation. During winter, in regions where it gets cold (maybe even snows), rattlesnakes will hibernate. Hibernation involves gorging on food in the fall to store fat to feed off during the hibernation period. Next, they will find a good hiding spot – a rocky den, a cave, gopher tortoise burrow, hole beneath a tree stump – where they will be safe from predation until spring. Once in this hibernaculum, they will lower their breathing and heart rate and allow their body temperature to drop. They go into a state of torpor where they are basically shut down. Many rattlesnakes use the same hibernacula each year, finding it by their sense of smell. Some species will share this space with several others – literally a den of snakes.
In the spring, when the air temperatures reach 70°F, they will emerge and immediately seek food. In some locations the summers will become very hot and so feeding and reproduction are on their minds before it becomes too hot, and they have to hide again. It is during these feeding/mating forays that many people encounter them. During this period they may move during periods of the day, and into locations they might avoid otherwise.
If they live in locations where summer can be very hot, they will repeat this behavior to avoid overheating – this is called aestivation. Another problem with hot summers is dehydration. Aestivation is more spontaneous than hibernation.
The eastern diamondback rattlesnake, the one often found on our barrier islands, lives only in the warmer parts of the southeastern U.S. It does get cold in some parts of their range, but they are not common where it snows. However, it does get very hot where they live and so even though hibernation is part of their life cycle, aestivation is common.
Next, we will look at reproduction.
References
Rubio, M. 2010. Rattlesnakes of the United States and Canada. ECO Herpetological Publishing & Distribution. Rodeo, New Mexico. pp. 307.
Gibbons, W., Dorcas, M. 2005. Snakes of the Southeast. The University of Georgia Press. Athens, Georgia. pp. 253.
Graham, S.P. 2018. American Snakes. John’s Hopkins University Press. Baltimore, Maryland. pp. 293.
by Rick O'Connor | Dec 22, 2025
Though encounters with Eastern Diamondback Rattlesnakes are rare, bites from them are even more rare, and deaths from those bites almost nonexistent, it is worth discussing the issues and remedies of a bite.
The eastern diamondback rattlesnake is a classic serpent found in xeric habitats like barrier islands and deserts. They can be found in all habitats on barrier islands.
Photo: Bob Pitts
About 8000 people are bitten by snakes each year in the U.S. and Canada. Most are on the hands of men who were engaging the snake. 95% of those bitten are trying to either catch or kill them. Annually less than 12 people die from some species of rattlesnake bite. Many are young or old, with a suppressed immune system or pre-existing medical condition. Many who die, for whatever reason, refused medical treatment.
Most lethal bites are those that reach the heart or brain. However most bites are on the extremities where tissue and nerve damage can occur, but death is less likely. One reason some may refuse medical treatment is cost. Antivenin treatments are expensive. Typical bites may require 4-6 vials and costs were between $1500-$3500/vial in 2010. Add to this the cost of hospital stays, and you can see how expensive it can be.
Another reason given as to why medical attention was not sought is the fact that many venomous snakes will give what is called a “dry bite”. As mentioned in earlier articles, snake venom is “expensive” for snakes to produce, and it is intended for prey – not predators. Rattlesnakes will often give what is called a “bluff bite” – striking with their head but not even opening their mouths. The injection of venom is a voluntary action by the snake, and they may choose to inject very little, if any, venom even if the fangs penetrate. It is believed that about 50% of the rattlesnakes are dry bites. That said, you should never gamble on whether you received venom or not, you should go to the hospital.
The venom itself is a cocktail of proteins, polypeptides, digestive enzymes, and other compounds. It is basically modified salvia – which already includes some digestive enzymes. Myotoxins are a large component of rattlesnake venom. Myotoxins attack muscle tissue, cause pain, discoloration, minor bleeding, and swelling. This can be accompanied by chills, sweats, dizziness, disorientation, tingling and numbness of mouth and tongue, metallic taste, vomiting, diarrhea, bloody stools, alternating blood pressure and heart rates, blurred vision, muscle spasms, and neurotoxins can paralyze diaphragm leading to asphyxiation.
To avoid envenomation problems wear closed-toed shoes when hiking in rattlesnake territory. Do not extend your hand into brushy/grassy areas – use your hiking stick instead. Watch stepping over, or sitting on, logs and stumps without close surveying. Do not touch dead rattlesnakes, if not dead long, they can still bite. Carry a cell phone.
What to do if bitten…
Call 911.
Call poison control if you have their number.
Get to a hospital.
Remove rings, watches, etc. – swelling will occur.
Keep bite at, or below, heart level.
Remain calm.
What NOT to do if bitten…
Do not cut the wound.
Do not suck venom out.
Do not apply a tourniquet.
Do not apply ice.
Do not drink alcohol.
Do not use electroshock treatment.
Envenomation from an eastern diamondback rattlesnake is a scary thing. However, there are many ways to avoid this problem, and there is basic treatment if you are. Remember few people are bitten, and very few die. Get medical attention as soon as you can.
References
Rubio, M. 2010. Rattlesnakes of the United States and Canada. ECO Herpetological Publishing & Distribution. Rodeo, New Mexico. pp. 307.
Gibbons, W., Dorcas, M. 2005. Snakes of the Southeast. The University of Georgia Press. Athens, Georgia. pp. 253.
Graham, S.P. 2018. American Snakes. John’s Hopkins University Press. Baltimore, Maryland. pp. 293.
