| Superclass Gnathostomata, Class Reptilia – Snakes, Turtles, etc. | | |
| Order Testudinata - Turtles | | |
| Chelydra serpentina | Snapping Turtle | declining but reasonably common across the island; on Nomans Land. |
| Chrysemys picta | Painted Turtle | common in freshwater ponds across the island and on Noman’s Land. |
| Pseudemys rubriventris | Red-bellied Turtle | former resident; remains have been found in Indian kitchen middens; see Waters (1962, 1966). |
| Clemmys guttata | Spotted Turtle | very rare and local on the main island and Chappaquiddick; moderately common on Nomans Land. |
| Terrapene carolina carolina | Eastern Box Turtle | now very rare and local; species of Special Concern in MA. |
| Trachemys scripta elegans | Red-eared Slider | Uncommon established in a few ponds. No longer sold in pet stores as of 2014 per Massachusetts law. |
| Chelonia mydas | Atlantic Green Turtle | offshore waters; 2 records; a Threatened species in MA |
| Eretmochelys imbricata | Atlantic Hawksbill Turtle | offshore waters; an Endangered species in MA and by Federal designation |
| Caretta caretta | Atlantic Loggerhead Turtle | offshore waters; uncommon; a Threatened species in MA and by Federal designation |
| Lepidochelys kempi | Kemp’s Ridley Turtle | offshore waters; an Endangered species in MA and by Federal designation |
| Dermochelys coriacea | Atlantic Leatherback Turtle | offshore waters; an Endangered species in MA and by Federal designation. |
| Order Squamata - Snakes | | |
| Coluber constrictor | North American Racer; Black Racer | uncommon from Chappy to Aquinnah along the south shore. No recent records from Oak Bluffs or Vineyard Haven |
| Opheodrys vernalis | Smooth Greensnake | uncommon but widespread |
| Lampropeltis triangulum | Eastern Milk Snake | somewhat common and widespread |
| Diadophis punctatus | Ring-neck Snake | rare and very local |
| Thamnophis sauritus | Eastern Ribbon Snake | uncommon and local except formerly on parts of Chappaquiddick where once common |
| Thamnophis sirtalis sirtalis | Common Gartersnake; Eastern Garter Snake | common and widely distributed; the only snake known on Nomans Land |
| Storeria dekayi | Northern Brownsnake, Dekay's Brownsnake | rare, small population found in Aquinnah 2020. |
| Storeria occipitomaculata ssp. occipitomaculata | Red-bellied Snake; Northern Redbelly Snake | very local and uncommon |