| 1 | The old boat jumping story |
The cottonmouth is one of the most feared snakes of the southern USA, primarily residing in waterways and swamps. It’s more than capable of killing innocent people, but is particularly notorious for the vast amount of wacky folklore surrounding it.
The most enduring rumour is that cottonmouths love to rest on overhanging branches, and will wait on them patiently as fishermen sail down a river. At the opportune moment, the cottonmouth will leap from its branch in a murderous rage, landing straight on the wooden deck below. What follows next is a massacre, as the cottonmouth proceeds to slaughter the entire captain and crew, who are usually panicking so wildly that the snake makes easy pickings of them.
This story is so enduring that many fishermen have abandoned their boats, or even blown the wooden deck in with a shotgun after hearing someone cry “snake!”. Others are too scared to go anywhere near confirmed cottonmouth rivers. The truth of course, is that cottonmouths have never been recorded to do this. They’re decent tree climbers, but almost never use those skills. The real character in the horror stories was the brown watersnake, which often basks on overhanging branches for hours without moving.
| 2 | The old water skiing story |
Another evil cottonmouth legend concerns a water skier, sometimes a mother with 4 kids, or sometimes a younger girl. The story, relayed by countless lifeguards at lakes, is that the girl was being dragged around by a boat, enjoying the adrenaline rush, when the line suddenly snagged on an old piece of barbed wire fencing.
The girl was sent flying, and had the dire luck to land straight in a breeding ball of cottonmouths, an entire group of snakes writhing together in a huddle. The snakes bit the girl 40-50 times, and when they finally pulled her body to shore, she died minutes later. Another version involves a young boy yelling at his friends “last one in’s a rotten egg”, who then leapt in and also landed on a fatal breeding ball.
This urban legend is as old as the United States itself. Nobody knows where it originally came from. It first circulated weekend tourist spots, then magazines, then viral emails, then forums, and finally social media. The earliest reference was in a 1967 memoir about Mississippi called North Toward Home. Whether anything similar really happened is unknown, but there’s one clue: unlike the common garter snake, the cottonmouth has never been recorded to form a breeding ball.
| 3 | The old chasing people story |
Another undying myth is that pretty much every snake found in a swamp is a cottonmouth, regardless of which state. There’s a phenomenon of Americans in Pennsylvania, New York, and Maryland insisting that their local lake harbours deadly cottonmouths, when the furthest north they’re known to inhabit is Virginia.
Like bears or sharks, the cottonmouth is considered to be a bloodthirsty maniac that has nothing on its mind other than killing people. Stories are legion of cottonmouths chasing people into gardens, charging after fishermen, and pursuing riverside campers until their last breath. The only solution is to run as far and as fast as your legs will carry you. If the cottonmouth wins the race, then all you can do is pray for a quick death.
Once again, the reality is slightly different. Cottonmouths are actually a slower than average snake, with bulky bodies that lack the nimbleness of a coachwhip. Despite the all-seeing power of the internet, nobody has ever uploaded a non-CGI video showing a cottonmouth charging after people. Like most snakes, they’d rather not be bothered at all.
| 4 | Hard facts and percentages |
Most old timers in Florida, Louisiana or Texas respond to a cottonmouth sighting by heading to the garden shed and grabbing their trusty, rusty shovel. But scientific studies have proven that like bears, the cottonmouth is just as scared of us as we are of them.
In a 2002 study, Mike Dorcas and Whit Gibbons marched around Florida and encountered 45 cottonmouths. 23 (51%) fled instantly, and 78% of the remainder opened their mouths wide in a defensive display. When 36 of the cottonmouths were picked up using a mechanical arm, only 13 (36%) bothered to bite down. Dorcas and Gibbons also stepped on 21 of the cottonmouths’ tails, which caused just 1 to bite their shoes.
Rather than chasing fishermen, the cottonmouths were particularly likely to flee (20% of snakes) when next to a body of water. 24% released a foul-smelling musk, and 33% vibrated their tails, in a weaker version of a rattlesnake’s rattle. The evidence points to a defensive snake rather than an unhinged loose cannon.
| 5 | Origin of the name |
Cottonmouths are a snake of endless names. The Latin term is Agkistrodon piscivorus, and the various localisms include swamp moccasin, snap-jaw, gapper, and swamp lion. The cottonmouth name simply comes from the pale white insides of its mouth, which it gapes at passers-by in a supposedly intimidating display. “Snap-jaw” or “trap-jaw” comes from the cottonmouth’s suddenly closing mouth; it tends to snap shut like a mouse trap the moment anyone touches them.
This snowy white mouth also doubles up as a near infallible ID trick. The muscular body is another sign, which is so thick that 1970s herpetologists struggled to hold onto them when extracting venom.
There’s also the huge, spade-shaped head, which is very distinct from the neck. Cottonmouths have vertical pupils (unlike brown watersnakes), and their eyes are spaced far apart, blocked by their bulky snout. The colour scheme is black, brown and olive, and younglings are similar, except for a yellow tip of the tail (instead of black), and a brighter overall appearance.
| 6 | Gigantic ones are regularly sighted |
Back in 2017, while working on wetland restoration in North Carolina, Frederick Boyce had the luck (or maybe misfortune) to stumble across a major cottonmouth stronghold, with over 100 compressed into a 25 acre zone. He dubbed it the Cottonmouth Acres, and kept the location a strict secret for conservation reasons. On May 10th 2021, he uploaded a picture to Facebook of a monster, a cottonmouth measuring at least 150cm (compared to an average of 65-90cm), but looking even bigger due to its massively thick body.
Rather than charging at Boyce, the cottonmouth was slithering very slowly out of a boggy ditch and up the weed-covered bank, taking its time. The wind was blowing, the skies were darkening, and a thunderstorm was rolling in, forcing the cottonmouth to get moving. The location was eastern North Carolina, and interestingly, the largest cottonmouth ever recorded (a 74 incher) was also recorded in North Carolina, near the Virginia border.
8 days later, Boyce came across the massive yet lazy cottonmouth barely any distance from its original location, resting under a large tree on the ditch’s opposite shore. 150cm is massive already, but locals occasionally claim to have encountered 7 footers. One thing’s for sure: it’s 1000 miles from Texas to North Carolina, and there’s a lot of poorly surveyed swampland in-between.
| 7 | They have their own road |
Many Canadian roads are closed seasonally because of hungry bears, but Illinois boasts the world’s only road to be closed because of snake crossings. This road lies in Shawnee National Forest, and bisects two prime spots of snake habitat.
To the west lies LaRue swamp, a humid bog which is perfect for the semi-aquatic cottonmouth to dwell in during summer. To the east lies the perfect winter habitat: towering limestone bluffs with numerous nooks and crannies, which are sheltered from the wind and retain warmth very effectively. The road is officially closed from March 15th to May 15th, and again from September 1st to October 30th, as the migrations can take up to 2 months. The road isn’t awash with vipers like a long-sealed European tomb, but it’s common to find 20 cottonmouths slithering around at once (pedestrians are still permitted).
In the early 1970s, locals were angry at the closure, as they had long enjoyed the sport of seeing how many snakes they could run over. Part of the problem was that the cottonmouths are in no rush. Because the dark tarmac absorbs sunlight so well, it makes Snake Road (real name LaRue road) a perfect place for basking. Copperheads and timber rattlesnakes are also seen on Snake Road, but the cottonmouth is the most numerous species.
| 8 | Not fussy, but prefers frogs |
Cottonmouths have a massively varied diet, but equally, they have to dodge a huge amount of predators. The combatants and contenders are endless in the swampy worlds in which they live. For example, cottonmouths have to dodge snapping turtles, a notoriously aggressive turtle which bites and thrashes whenever picked up, and assaults members of its own kind. They have to dodge the gaze of blue herons and whooping cranes waiting patiently overhead.
Like mud snakes, American alligators are often on their tail. They even have to dodge hungry fish. The cottonmouth equivalent of a great white shark is the greedy-looking largemouth bass, a prized catch of fishermen (possibly the same fishermen who think that cottonmouths are trying to murder them).
Cottonmouths will eat rats and weasels with no thought, and birds like American sparrows. They eat many species of snake, including mud snakes, corn snakes, plainbelly watersnakes, brown watersnakes, western ribbon snakes, yellow-bellied kingsnakes, and western diamondback rattlesnakes. But their favourite dish is frog, and particularly frogs of the Lithobates family, AKA the American water frogs. Members they’ve been spotted eating include pig frogs, green bullfrogs, American bullfrogs, pickerel frogs, and southern leopard frogs.
| 9 | Deaths are rare |
Cottonmouths easily defeat their constantly confused relative the copperhead for pound to pound venom potency. The LD50 rating is 2.04mg, compared to only 10.9mg for copperheads. The venom yield is also in another league, at 80-170mg versus 40-75mg. However, they fail next to the deadliest rattlesnake species, including the tiger rattlesnake at LD50 0.06mg and the Mojave rattlesnake at 0.18mg.
If a cottonmouth does decide to invade your fishing boat one stormy night, then you’ll probably live to tell the tale, as the last notable death occurred in 1971, when Bryan L. Bristow was bitten on the hand while collecting snakes into a bag. A death in 2015 was ruled inconclusive, as 37 year old Gilbert De Leon had a lethal level of oxycodone in his system at the time.
Cottonmouth venom clearly specialises in cytotoxic powers, the ability to destroy cell walls, cell membranes, and cell contents. A study monitored 32 cottonmouth bites from 2013-2017, and found that swelling occurred in all patients, which was severe enough in 65% to cross one major joint. The dangers were mostly local, as the systemic effects were limited to diarrhoea (one victim) and vomiting (16%). Cottonmouth venom is missing the brain-frazzling neurotoxins of rattlesnakes.
| 10 | Best of the rest |
Not every cottonmouth myth works in a positive way. Another classic is that they can’t bite underwater, and that diving below the surface would be smart, but they’re more than capable of biting anywhere (except maybe a volcano crater). Their hunting strategy is primarily ambush, waiting in thick swampside weeds for a frog to appear. Cottonmouths are nocturnal, another difference to the oft-confused brown watersnake (which is diurnal).
Female cottonmouths lay live young rather than eggs, and in medium quantities of 6-20. It’s believed that baby cottonmouths stick with their mothers for a few days after birth. Males are violent in their attempts to conquer a female, wrestling with other males like a drunk in a bar, so that the victor takes the spoil. Sometimes, the males won’t touch, but one male will perform a combat dance where they slither back and forth in front of females, to prove its cottonmouth prowess.
The record lifespan for a cottonmouth was 20.5 years, but first things first, they have to make it to adulthood without being eaten. Only 2-3 hatchlings from each clutch survive on average.