A Mass Emergence of Cottonmouths - Observation of the Week, 4/21/19

Our Observation of the Week is this large group of Cottonmouths, seen in the United States by @wildlandblogger!

A few weeks go, while on a hike in a central part of North America, looking for birds and plants Jared Gorrell had gotten a bit lost but was able to use his phone’s GPS to navigate back to his car. However, something caught his eye. “I noticed a pond along the way and decided to look around it and see if I could find some birds, insects or plants that would be new for me,” he recalls.

I didn’t realize the pond had dirt cliffs around it, and as I walked downslope I nearly stumbled over the edge of one of these, and then I looked down into that pile of cottonmouths. I backed up and sat down, and then proceeded to put my hand down six inches from a juvenile cottonmouth. After moving it out of the way with a long stick and then going uphill to have a slight panic attack over the close call, I came back down to take pictures and count.

You definitely don’t want to get bitten by a cottonmouth, which is a viper endemic to the United States. While fatalities are rare, this species’ cytotoxic venom can cause severe tissue damage and pain. Although it has a fierce reputation, this snake (like most others) is not aggressive (PDF) and will choose to either escape or engage in threat displays when encountering a human. One of those displays involves showing off the bright white interior of its mouth, giving the species its common name (although it’s also known as a water moccasin, as well). These semi-aquatic snakes eat a wide variety of prey and are often found near water sources, although usually not in such large numbers.

“What you see in the photo is a pile of sunning cottonmouths that have recently emerged from a den site, presumably someplace on a nearby hill,” says Jared.

In this temperate area, snakes form groups like this in sunny spots to warm up more quickly, after leaving a cool underground refuge where they spent the previous winter. Unfortunately, many of these “mass emergences” have been targeted by locals afraid of venomous snakes, so this “ball of cottonmouths” is a rare sighting nowadays, and I’ve intentionally kept the location private for that reason...since poaching and/or harassment are serious issues for reptiles like these cottonmouths, I generally obscure or privatize my herp locations.

Jared, who tells me “at three years old I spoke vaguely with an Australian accent because I watched Steve Irwin, the Crocodile Hunter, so often,” will soon be graduating from Southern Illinois University - Carbondale with a degree in plant biology specializing in ecology, and this summer plans on “working with the Critical Trends Assessment Program in Illinois surveying plants and insects at various field sites across the state.”

And during his free time, Jared’s out and about looking for plants, birds, reptiles and amphibians, and has “recently developed an interest in dipnetting for fish and netting for dragonflies and butterflies.” He uses iNat to “log all of my sightings, compete with friends, and share my observations with those around me. iNaturalist has inspired my interest in dragonflies, butterflies and fish, especially fish since they’re so under-reported on this website. I definitely take a lot more pictures now too!”

- by Tony Iwane

- Bird and Moon has a great comic about the myths and facts surrounding cottonmouth snakes.

- Here’s thorough advice on how to survive a snakebite in the wilderness. (Disclosure: I previously worked with Jordan Benjamin, founder of The Asclepius Snakebite Foundation)

- Water snakes of the genus Nerodia are often mistaken for cottonmouths. The University of Florida has a nice resource showing you how to differentiate them.

Posted by tiwane tiwane, April 21, 2019 23:23



Congratulations, Jared!! Great to hear you'll be working with CTAP!

Posted by missgreen about 1 year ago (Flag)

Amazing stuff! Well done!

Posted by susanhewitt about 1 year ago (Flag)

Eeep. Nice observation!

Posted by chlorophilia about 1 year ago (Flag)


Posted by jamie240 about 1 year ago (Flag)


Posted by deqinglan about 1 year ago (Flag)

Yikes... Good for Jared for staying calm!

Posted by alicemaryherden about 1 year ago (Flag)

How exciting :)

Posted by carolr about 1 year ago (Flag)

What an event! You are to be applauded for your stoicism and equally your great respect for these noble reptiles!

Posted by loriorden about 1 year ago (Flag)

bet that was kind of exciting! I've stumbled across similar groups in spring in Hoosier National Forest (not cottonmouth snakes though) on sunny days in spring -- thanks for sharing your photo.

Posted by martinlucas about 1 year ago (Flag)

As a child, I would walk through the woods down to the San Jacinto River in Harris County, and I've seen the same type of group.... scarey; i moved away silently..

Posted by twylabirdjean about 1 year ago (Flag)

I lived in Lake Charles, Louisiana for five years from elementary school to high school. I remember tails of people water skiing and falling into a ball of Cottonmouths and perishing. I now doubt any such occurrence actually happened due to the temperature of the water at this time of year - cool to warmer and snakes having already dispersed at this time. But this observation does confirm the basis of the myth, wouldn't you say? Not impossible, but improbable. But then the time for most people's water skiing would be when it was comfortable to wear a bathing suit, not a jacket or sweater. Too bad Ross Allen isn't alive to tell us his story about this species of snake with which he was so familiar.

Cottonmouths are a fascinating species and, despite growing up in their habitat and seeing plenty of them, really, they still offer up new and challenging information about themselves. Thank you for your good work and courage to stay calm enough to complete your observation.

Posted by billarbon about 1 year ago (Flag)

Wow! A great observation!

Posted by connlindajo about 1 year ago (Flag)

Wow that's incredible! I love how instead of running away in shock you head back for photos :) It makes a good story as well as a great observation!

Posted by lisa_bennett about 1 year ago (Flag)

You can see balls of cottonmouths underwater in the Potomac River above the Falls

Posted by elbobo about 1 year ago (Flag)

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