Snakes & Lizards

Kingdom - Animalia

Phylum - Chordata

Class - Reptilia

Order - Squamata

Families in Illinois


  • Viperidae
  • Colubridae*


  • Scincidae
  • Anguidae
  • Phrynosomatidae
  • Teiidae
  • Dekay's Brownsnake

  • Western Ribbonsnake

  • Common Gartersnake

  • Ground Skink

  • Eastern Fence Lizard

  • Massasauga

  • Diamond-backed Watersnake

  • Smooth Greensnake

  • Plains Gartersnake

  • Common Watersnake

  • Eastern Hog-nosed Snake

  • Common Watersnake

  • Common Five-lined Skink

  • Skink

  • Timber Rattlesnake

  • Ring-necked Snake

  • Copperhead

  • Six-lined Racerunner

  • North American Racer

  • Queensnakes

  • Gophersnake

  • Cottonmouth

  • Eastern Hog-nosed Snake

  • North American Racer

  • Worm Snake

  • Kirtland's Snake

*some recognize Dipsadidae and Natricidae as separate families

Squamates have:

  • the ability to open their jaws wide because their quadrate bones (back part of the jaw) can move
  • skin of horny scales or shields
  • no shells a highly modified skull,
  • males have a hemipenis (paired penes).


Reproduction can be viviparous (live birth), ovoviviparous (live birth from an egg incubated within the female), ore oviparous (egg laying).

Squamates are divided into three groups:



There are approximately 5,800 species of lizard in the world, 7 of which are found in Illinois.


  • have external ear openings
  • most have 4 limbs
  • most have eyelids, though some, like gekkos, have lost them
  • found on all contents except Antarctica


There are approximately 3,400 species of snake in the world, 38 of which are found in Illinois.


  • lack movable eyelids.
  • lack limbs.
  • lack external ears.
  • are found on all continents except Antarctica.
  • Ireland, Iceland, Greenland, and Hawaii have no native snakes.
  • Sea snakes are found in the Indian and Pacific Oceans.

Worm Lizards

There are over 180 species, none of which are found in Illinois.

Worm Lizards:

  • lack limbs, except Bipes.
  • lack external ears.
  • have limited eyes.
  • are fossorial (live underground).
  • have a solid bony skull to aid in digging.
  • are found in North America, Europe, Africa, South America, the Middle-East and Caribbean.

Illinois Lizards:

 Illinois Snakes:

Colubridae - Colubrids

Subfamily: Colubrinae

  • lack spines on lumbar vertebrae.
  • most are oviparous.
  • some have smooth scales and some have keeled (ridged) scales.

Scarletsnake Cemophora coccinea
North American Racer Coluber constrictor
Great Plains Ratsnake Pantherophis emoryi
Gray Ratsnake Pantherophis spiloides
Eastern Foxsnake Pantherophis vulpinus
Yellow-bellied Kingsnake Lampropeltis calligaster 
Black Kingsnake Lampropeltis nigra
Milksnake Lampropeltis triangulum 
Coachwhip Masticophis flagellum 
Rough Greensnake Opheodrys aestivus 
Smooth Greensnake Opheodrys vernalis 
Gophersnake Pituophis catenifer
Flat-headed snake Tantilla gracilis
Lined snake Tropidoclonion lineatum
Eastern Smooth Earthsnake Virginia valeriae 


Subfamily: Natricinae

  • have spines on lumbar vertebrae.
  • North American species have keeled scales.
  • North American species are viviparous.

Kirtland’s Snake Clonophis kirtlandii
Mississippi Green Watersnake Nerodia cyclopion 
Plain-bellied Watersnake Nerodia erythrogaster
Southern Watersnake Nerodia fasciata
Diamond-backed Watersnake Nerodia rhombifer 
Common Watersnake Nerodia sipedon
Graham’s Crayfish snake Regina grahamii 
Queensnake Regina septemvittata 
Dekay's Brownsnake Storeria dekayi 
Red-bellied Snake Storeria occipitomaculata
Western Ribbonsnake Thamnophis proximus 
Plains Gartersnake Thamnophis radix 
Eastern Ribbonsnake Thamnophis sauritus 
Common Gartersnake Thamnophis sirtalis 


Subfamily: Dipsadinae

  • rear-fanged - have enlarged teeth at the back of the mouth to inject venom into prey/
  • most are oviparous.

Common Wormsnake Carphophis amoenus
Ring-necked Snake Diadophis punctatus
Red-bellied Mudsnake Farancia abacura 
Western Hog-nosed Snake Heterodon nasicus
Eastern Hog-nosed Snake Heterodon platirhinos 

Viperidae - Vipers

North American vipers

  • have a pit between nostril and eyes
  • have vertical slit-like pupils
  • have venom glands which create a triangular head
  • are viviparous

Copperhead Agkistrodon contortrix *
Cottonmouth Agkistrodon piscivorus *
Massasauga Sistrurus catenatus *
Timber Rattlesnake Crotalus horridus *
* Venomous species

 Keeled scales have a ridge, resulting in a rough surface.























Pit vipers have a pit between eye and nostril and a vertical slit of a pupil.