Dekay’s Brownsnake: One of America’s Most Misidentified Snakes

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If you’ve ever found a snake in a backyard that you didn’t recognize, there is a very good chance it is a harmless Dekay’s or Florida Brownsnake (Storeria dekayi or S. victa), but without knowing what species your snake is, it is very natural to want some answers. What species is the snake? Where did it come from? Is it someone’s pet? Is it venomous? If you found it in the mouth of a pet or hands of a child, you may, understandably, have concerns. Thankfully, there are many resources to help you identify a snake quickly. Some online services growing in popularity use artificial intelligence to suggest identifications including iNaturalist.org, WhatTheHerp.com, and the Google Lens app, but their algorithms are not always correct, so you need to do some additional research to verify the ID. You might also have a field guide on hand and try to identify the snake the old-fashioned way. If you’re like hundreds of thousands of people online, you might post a picture in a social media group that specializes in snake identification, or tag @WildSnakeID in a tweet. In a reptile and amphibian identification group that I help run on Facebook, Brownsnakes are one of the species posted most often, but when it comes to crowdsourcing and ID, an expert isn’t necessarily the first person who will comment on your post, and the Brownsnake really takes the cake when it comes to wrong answers.

* Note: The name “Brownsnake” also applies to two Australian species; the highly venomous Eastern Brown Snake (Pseudonaja textilis) and the mildly venomous Brown Tree Snake (Boiga irregularis). The Brown Tree Snake is also an invasive species in Guam.

Dekay's Brownsnake displaying typical coloration and pattern for the species as described in the third paragraph. Photo by Jay Plotkin.

Brownsnakes are some of the most widespread, non-venomous snakes in North America, but they tend to be very secretive, mostly coming out to forage on slugs and snails at night, so few people, apart from herpetologists and seasoned naturalists, know what they are until the day they find one by their front step. In the south, most people in rural areas know about Racers (Coluber constrictor), and in the northeast you’ll be hard pressed to find someone who hasn’t seen a Gartersnake (Thamnophis sirtalis). The Brownsnake, on the other hand, which is abundant through much of the Eastern United States, flies under the radar, so people are often perplexed when they see one. Because Brownsnakes are very small, it is common for folk think they are babies of a larger species, but when people post their Brownsnake pictures online for identification, it really runs the gamut in terms of what IDs folk will come up with. Rattlesnake, Copperhead, Hog-nosed Snake, Ratsnake, Gartersnake etc. There really is no upper limit with this species, so you should wait for a couple people to verify the ID before trusting the first answer. Better yet, learn the Brownsnake’s field marks! So, how can you know if a snake is a Brownsnake and not another species?

Black markings on the body and face are great Brownsnake field marks, but newborns are much darker and have a light collar around their neck. Photos in-hand by Kiley Briggs. Juvenile photo by Jim Andrews.

Brownsnakes are typically brown or grayish-brown in body color. They have a light stripe down the center of their back that is bordered with black spots on each side, sometimes taking the form of a checkerboard pattern. Their underside is white or tan, and they have a black spot on the top of the head, black sideburns, a black spot under the eye, and black marks similar to parentheses on each side of the neck. Brownsnakes are usually about 1 foot long (18 inches max) and have keeled scales (you may need a hand lens to see, but there is a lengthwise ridge on each of their scales). When very small, they have a white ring around their neck that extends forward and under the eyes. So, long story short, there is a lot going on with Brownsnakes that, at a glance, are a fairly non-descript species, but once you’ve seen two or three, there really is no mistaking a Brownsnake for anything else. The most similar species in most areas will be Red-bellied Snakes (S. occipitomaculata) and small Gartersnakes. And, like any other harmless snake, when they are scared, a Brownsnake may flatten its head into a triangular shape, so you are free to do-away with the belief that triangular heads mean the snake is venomous (this is one of the most widely spread myths about snakes).  

This sequence compiled by Chelsea Roman and Jenna Bonnacis shows the wide range of incorrect IDs that sometimes flood identification requests of Brownsnakes when posted to local groups. Joining a group that specializes in reptile and amphibian identification will help ensure a correct ID (but sometimes you’ll get a bad answer before an expert can chime in). Click images for higher a higher resolution view. Credit of original photos unknown. 

Because Brownsnakes are active mostly at night, people usually only find them while moving objects around in their yard that the snakes are hiding under. Stacked wood, cardboard or tarps in gardens, and piles of rocks are great hiding spots for a Brownsnake. Snakes, as a whole, are very nice animals to have around, and Brownsnakes definitely pull their weight as far as good yard-mates go, devouring any snail or slug they encounter during their evening escapades. While I do not have Brownsnakes in my part of Vermont, I leave a small pile of loosely stacked flat rocks by my raised beds to encourage a related species with a very similar diet, the Red-bellied Snake, to take up residence. So if you find a Brownsnake in your yard, there is no need for alarm. Even if a Brownsnake were to bite when you pick one up (which they almost never do), their heads are so small that they are physically incapable of hurting, or even scratching you, but they may produce a foul-smelling musk when handled, so some people prefer to wear gloves. As far as humans are concerned, daffodils pose as much of a threat than any Brownsnake in North America. If you are a slug, however, a Brownsnake is very bad news. When you find a Brownsnake in your yard or in a road, you can just move it out of harm’s way, ideally to a sunny hiding spot nearby or to whatever side of the road it was headed. With any luck the Brownsnake will continue to thrive and keep working on the local slug and snail populations for years to come.

Records from iNaturalist show that Dekay's and Florida Brownsnakes are widespread in almost the entire eastern United States.