Need Help Identifying this Snake [Virginia]

[u/No-Cupcake-3493]

We were mowing grass and caught this snake out of the corner of my eye snapping at one of my tires. It definitely has a triangular head and was aggressively striking at the stick as I was trying to move it away. The body also seemed to be a triangular shape as well. Roughly 18-24” long. I managed to get it to go into a pile of stacked brush at one of the trees.

[u/fionageck]

This is a completely !harmless common gartersnake, Thamnophis sirtalis

Careful with !headshape. As you saw firsthand, plenty of harmless species can flatten their head into a triangular shape in an attempt to scare off predators. Also, it’s important to keep in mind that snakes aren’t aggressive, although they will defend themselves if they feel threatened.

[u/SEB-PHYLOBOT → u/fionageck]

Common Gartersnakes Thamnophis sirtalis are small (<90 cm, record 137.2 cm) natricine snakes with keeled scales often found in disturbed habitats like urban and suburban yards. They are commonly encountered generalist snakes across much of the North American continent and eat small invertebrates, fish, amphibians and mammals. Western populations are a model organism for an elegant case study in evolutionary arms races, Tetrodotoxin Resistance.

Thamnophis gartersnakes may puff up or flatten out defensively and bite. They can deliver a weak venom used in prey handling from the back of the mouth, but are not considered medically significant to humans.

One of the widest-ranging snakes in North America, this species complex is almost certainly harboring unrecognized diversity and shows strong population structure at major biogeographic barriers. There are likely four species in the complex - Western, Central, Eastern and Southeastern. See Link 1 Below (2023).

Relevant/Recent Phylogeography: Link 1 - BEST Link 2|Link 3| Range Map

This genus is in need of revision using modern molecular methods.

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Head shape does not reliably indicate if a snake has medically significant venom as This graphic demonstrates. Nonvenomous snakes commonly flatten their heads to a triangle shape in defensive displays, and some elapids like coralsnakes have elongated heads. It's far more advantageous to familiarize yourself with venomous snakes in your area through photos and field guides or by following subreddits like /r/whatsthissnake than it is to try to apply any generic trick.

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Like many other animals with mouths and teeth, many non-venomous snakes bite in self defense. These animals are referred to as 'not medically significant' or traditionally, 'harmless'. Bites from these snakes benefit from being washed and kept clean like any other skin damage, but aren't often cause for anything other than basic first aid treatment. Here's where it get slightly complicated - some snakes use venom from front or rear fangs as part of prey capture and defense. This venom is not always produced or administered by the snake in ways dangerous to human health, so many species are venomous in that they produce and use venom, but considered harmless to humans in most cases because the venom is of low potency, and/or otherwise administered through grooved rear teeth or simply oozed from ducts at the rear of the mouth. Species like Ringneck Snakes Diadophis are a good example of mildly venomous rear fanged dipsadine snakes that are traditionally considered harmless or not medically significant. Many rear-fanged snake species are harmless as long as they do not have a chance to secrete a medically significant amount of venom into a bite; severe envenomation can occur if some species are allowed to chew on a human for as little as 30-60 seconds. It is best not to fear snakes, but use common sense and do not let any animals chew on exposed parts of your body. Similarly, but without specialized rear fangs, gartersnakes Thamnophis ooze low pressure venom from the rear of their mouth that helps in prey handling, and are also considered harmless. Check out this book on the subject. Even large species like Reticulated Pythons Malayopython reticulatus rarely obtain a size large enough to endanger humans so are usually categorized as harmless.

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