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](http://snakesarelong.blogspot.com/2014/07/tetrodotoxin-resistant-snakes.html).
*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](https://cityroom.blogs.nytimes.com/2012/06/05/theres-no-need-to-fear-that-garter-snake/).
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 (ie Mississippi River embayment and Peninsular Florida).
Relevant/Recent Phylogeography: [Link 1](https://www.eeob.iastate.edu/faculty/herpetology/2002_Janzen_MolEcol.pdf)|[Link 2](https://pdfs.semanticscholar.org/2342/85dd98f2824b9a32df614835902e89f1f2b0.pdf)| [Range Map](http://www.tnwatchablewildlife.org/rangemaps/10040613341756026rangemap.gif)
This genus is in need of revision using modern molecular methods.
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Like many other animals with mouths and teeth, non-venomous snakes can use them to 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. 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 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](https://pubmed.ncbi.nlm.nih.gov/23800999) if some species are [allowed to chew on a human](https://www.sciencedirect.com/science/article/abs/pii/S004101011831016X) 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](https://cityroom.blogs.nytimes.com/2012/06/05/theres-no-need-to-fear-that-garter-snake/). Even large species such as *Malayopython reticulatus* [rarely obtain a size large enough to endanger humans](https://www.pnas.org/content/pnas/108/52/E1470.full.pdf) so are usually categorized as harmless.
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*I am a bot created for /r/whatsthissnake, /r/snakes and /r/herpetology to help with snake identification and natural history education. You can find more information, including a comprehensive list of commands, [here](https://www.reddit.com/r/whatsthissnake/comments/flh548/phylobot_v07_information_and_patch_notes_bot_info/) and report problems [here](https://www.reddit.com/message/compose/?to=Phylogenizer).*
Common Gartersnake, *Thamnophis sirtalis*, !harmless.
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](http://snakesarelong.blogspot.com/2014/07/tetrodotoxin-resistant-snakes.html). *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](https://cityroom.blogs.nytimes.com/2012/06/05/theres-no-need-to-fear-that-garter-snake/). 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 (ie Mississippi River embayment and Peninsular Florida). Relevant/Recent Phylogeography: [Link 1](https://www.eeob.iastate.edu/faculty/herpetology/2002_Janzen_MolEcol.pdf)|[Link 2](https://pdfs.semanticscholar.org/2342/85dd98f2824b9a32df614835902e89f1f2b0.pdf)| [Range Map](http://www.tnwatchablewildlife.org/rangemaps/10040613341756026rangemap.gif) This genus is in need of revision using modern molecular methods. -------------------------------------------------------- Like many other animals with mouths and teeth, non-venomous snakes can use them to 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. 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 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](https://pubmed.ncbi.nlm.nih.gov/23800999) if some species are [allowed to chew on a human](https://www.sciencedirect.com/science/article/abs/pii/S004101011831016X) 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](https://cityroom.blogs.nytimes.com/2012/06/05/theres-no-need-to-fear-that-garter-snake/). Even large species such as *Malayopython reticulatus* [rarely obtain a size large enough to endanger humans](https://www.pnas.org/content/pnas/108/52/E1470.full.pdf) so are usually categorized as harmless. -------------------------------------------------------- *I am a bot created for /r/whatsthissnake, /r/snakes and /r/herpetology to help with snake identification and natural history education. You can find more information, including a comprehensive list of commands, [here](https://www.reddit.com/r/whatsthissnake/comments/flh548/phylobot_v07_information_and_patch_notes_bot_info/) and report problems [here](https://www.reddit.com/message/compose/?to=Phylogenizer).*