This chart was compiled by Michael Iacchetta using snake length data from the Vermont Reptile and Amphibian Atlas Database during February of 2013 and was updated in 2025. These are total lengths measured from the tip of a snake’s nose to the tip of its tail. The lengths of large adults of each Vermont species were averaged to determine their average adult length. Snake species were organized by average length, and this average includes the longest 10% from each species. For the 2025 update, we checked to see if the largest individuals for each species had changed (or had been corrected) and adjusted the average adult sizes or record sizes only as needed.
In the table below, the lengths in the left numerical column are the lengths you would expect for mature adults of these species in Vermont. The right numerical column represents the number of individuals found within the top 10% of records for that species in the 2013 analysis. The lengths in the middle numerical column are the largest reliably-documented snake of that species from Vermont. Can you document a larger one?
| Length Data for the Longest (Top 10%) Vermont Snakes | ||||
|---|---|---|---|---|
| Measured in inches from the tip of the nose to the tail (TBL) | ||||
| Species | Average Length | Longest Reported in Vermont | Sample Size | Person(s) Who Recorded Longest |
| Red-bellied Snake | 12.9 | 13.4 | 33 | Jim Andrews, Kate Kelly, Erin Talmage |
| Dekay’s Brownsnake | 16 | 19 | 7 | Gary Smith |
| Ring-necked Snake | 17 | 18.7 | 14 | Taylor Swanson |
| Smooth Greensnake | 20.4 | 24 | 7 | Chris and Clara Slesar & Adrie Kusserow |
| Eastern Ribbonsnake | 35.6 | 44.5 | 10 | Taylor Swanson |
| Common Gartersnake | 36.6 | 41 | 127 | Eric Wardle |
| Eastern Milksnake | 44 | 46.8 | 18 | Spencer Hardy & Maxwell Shaw-Jones |
| Common Watersnake | 49.9 | 54.5 | 11 | The Orianne Society & Kiley Briggs |
| Timber Rattlesnake | 55.1 | 57.5 | 7 | UVM Herpetology Class |
| North American Racer | 68.8 | 71.7 | 5 | Herp Atlas & VT Fish & Wildlife & USFWS |
| Central Ratsnake | 75.4 | 77.8 | 11 | Sheri Young & Ethan Mulcahy |
