| Snake
Study Guide |
Remember that you should be able to identify specimens to
family by external morphological characteristics alone. Do not rely
upon coloration characteristics since these are often bleached out in
preserved specimens. Typical coloration patterns also tend to vary
greatly in nature. The following information was presented in lab
at each station.
Families of snakes
Snakes of Connecticut
Snakes of Connecticut
Colubridae
Colubrinae
Coluber constrictor
Elaphe obsoleta
Lampropeltis triangulum
Opheodrys vernalis
Natricinae
Nerodia sipedon
Storeria dekayi
Storeria occipitomaculata
Thamnophis sauritus
Thamnophis sirtalis
Xenodontinae
Carphophis amoenus
Diadophis punctatus
Heterodon platyrhinos
Viperidae
Agkistrodon contortrix
Crotalus horridus
Carphophis amoenus (Eastern worm snake)
Family Colubridae (Xenodontinae)
Morphological characteristics:
- small, adapted for fossorial life
- reduced eyes, narrow head
- tail short and sharply pointed
- 13 dorsal scale rows
- dorsal scales smooth
- anal plate divided
Living specimens:
- pinkish-brown in color
Coluber constrictor (Black racer)
Family Colubridae (Colubrinae)
Morphological characteristics:
- long and slender
- rounded in cross-section (Elaphe obsoleta like loaf of bread in cross-section)
- scales smooth (scales in Elaphe obsoleta are keeled)
- 15 dorsal scale rows at posterior end of body
- anal plate divided
- usually 7 upper labial scales
Living specimens:
- glossy black on dorsal surface, dark gray or black on venter
- chin and underside of neck are yellowish-white (Elaphe obsoleta has pure white chin)
Diadophis punctatus (Northern ringneck snake)
Family Colubridae (Xenodontinae)
Morphological characteristics:
- small and slender
- scales smooth and glossy
- nasal plate divided
- anal plate divided
Living specimens:
- yellow or orange neck band
- dark gray or black head and dorsum
- bright yellow or orange venter
Elaphe obsoleta (Black rat snake)
Family Colubridae (Colubrinae)
Morphological characteristics:
- rough scales with weak keels (Coluber constrictor has smooth scales)
- heavier body than Coluber constrictor
- shaped like loaf of bread in cross section
- <30 dorsal scale rows
- anal plate divided
- 8 upper labial scales
Living specimens:
- solid black in color, white chin
- juveniles purplish gray with dark blotches
Heterodon platyrhinos (Eastern hognose snake)
Family Colubridae (Xenodontinae)
Morphological characteristics:
- upturned, hard snout
- rostral scale turned upward and keeled
- stocky body
- scales keeled
- anal plate divided
Living specimens:
- pattern and coloration variable: some mottled with background of yellow, brown, or red; others almost black
- venter mottled gray
Lampropeltis triangulum (Eastern milk snake)
Family Colubridae (Colubrinae)
Morphological characteristics:
- scales smooth
- usually 21 dorsal scale rows
- dorsal scales smooth
- anal plate not divided
Living specimens:
- adults with red or brown blotches edged in black on purple or gray background
- juveniles more reddish than adults
Nerodia sipedon (Northern water snake)
Colubridae (Natricinae)
Morphological characteristics:
- relatively heavy-bodied with rough, keeled scales
- does not have the triangular head characteristic of Agkistrodon contortrix
- 21+ dorsal scale rows
- anal plate divided
Living specimens:
- pattern variable, generally brown with bands across body
- markings distinct as juveniles, darken into uniform brown with age
Opheodrys vernalis (Smooth green snake)
Family Colubridae (Colubrinae)
Morphological characteristics:
- no keels on scales
- 17 dorsal scale rows
- anal plate divided
Living specimens:
- solid green in color, venter yellow or white
Storeria dekayi (Dekay’s snake, northern brown snake)
Family Colubridae (Natricinae)
Morphological characteristics:
- small and slender
- scales are keeled
- usually 17 dorsal scale rows
- anal plate divided
- 7 upper labial scales
- 1 preocular scale
Living specimens:
- nondescript and brown in color
- dorsum dull brown or tan, lighter vertebral band bordered by rows of black spots
- venter greenish to grayish white
- sides of head light
- distinct dark spot between each eye
- dark spot on neck
Storeria occipitomaculata (Red-bellied snake)
Family Colubridae (Natricinae)
Morphological characteristics:
- scales keeled
- anal plate divided
- 15 dorsal scale rows
- 6 upper labial scales
- two preocular scales
Living specimens:
- bright red venter
- light spots in occipital region behind head
- dorsal color gray or black
Thamnophis sauritus (Eastern ribbon snake)
Family Colubridae (Natricinae)
Morphological characteristics:
- long and slender
- tail long in proportion to rest of body
- < 27 dorsal scale rows
- 7 upper labial scales
- scales keeled
- anal plate not divided
Living specimens:
- three distinct yellow stripes on dark background
- lateral stripes on scale rows 3 & 4
- dark stripe below lateral yellow stripe on each side
Thamnophis sirtalis (Eastern garter snake)
Family Colubridae (Natricinae)
Morphological characteristics:
- compared to T. sauritus, tail shorter in proportion to body
- < 27 dorsal scale rows
- scales keeled
- anal plate not divided
- 7 upper labial scales
Living specimens:
- less distinct stripes than T. sauritus
- can be spotted or striped
- lateral stripes on scale rows 2 & 3
Agkistrodon contortrix (Northern copperhead)
Family Viperidae (Crotalinae)
Morphological characteristics:
- triangular head shape
- heat-sensing pit
- stocky body
- tail pointed without rattle
- scales weakly keeled
- anal plate not divided
Living specimens:
- coppery color
- hourglass-shaped bands across back
Crotalus horridus (Timber rattlesnake)
Family Viperidae (Crotalinae)
Morphological characteristics:
- triangular head shape
- heat-sensing pit
- stocky body
- rattle
- scales distinctly keeled
- area between eyes with small scales
Living specimens:
- two color phases: yellowish with dark brown or black bands or nearly all black with indistinct bands
- tail black
Families of snakes
Snakes of Connecticut
Families of snakes
Scolecophidia
Anomalepidae
Leptotyphlopidae
Typhlopidae
Alethinophidia
Aniloidea
Aniliidae
Uropeltidae
Macrostomata
Boidae
Boyleriidae
Loxocemidae
Tropidophiidae
Xenopeltidae
Caenophidia
Acrochordidae
Colubroidea
Colubridae
Elapidae
Viperidae
Atractaspidae
Anomalepidae
No specimens available
Leptotyphlopidae
- small, burrowing snakes, thin bodies
- eyes vestigial, lack brille, covered by scales
- retain vestiges of pelvic girdle, sometimes as horny projections
- no gastrosteges
- ventral scales transversely elongated
- 14 scale rows at midbody
Specimens on display:
Leptotyphlops sp.
Leptotyphlops conjunctus
Leptotyphlops distanti
Leptotyphlops goudotii
Leptotyphlops phenops
Typhlopidae
- small, blind, burrowing snakes
- similar to typhlopids
- sharp snout, distinct rostral shield for burrowing
- retain vestiges of pelvic girdle
- eyes covered by scales
- ventral scales transversely elongated
- 20 scale rows at midbody
Specimens on display:
Typhlops sp.
Typhlops richardi
Aniliidae
No specimens available
Uropeltidae
- burrowing snakes
- no vestigial pelvic bones or limbs
- eyes reduced, lack brille
- gastrosteges reduced or absent
- tip of tail with enlarged, rigid scale with two points or circular area covered with thick, spiny scales
Specimens on display:
Uropeltis sp.
Boidae
- retain vestiges of pelvic girdle and hind limb bones
- gastrosteges narrower than colubrids
- pythons have premaxillary teeth, boas do not
- some with heat-sensitive pits on labial scales
- scales on top of head behind eyes small
- chin shields not enlarged
Boinae: no premaxillary teeth
Erycinae: wedge-shaped head, some with pronounced canthus rostralis
Pythoninae: premaxillary teeth present
Specimens on display:
Boinae
Charina (Lichanura) trivirgata
Charina bottae
Corallus (Boa) caninus
Corallus (Enhydris) cookii
Epicrates cenchria
Erycinae
Calabaria reinhardtii
Gongylophis (Eryx) conicus
Pythoninae
Morelia spilota
Morelia viridis
Python regius
Boyleriidae
No specimens available
Loxocemidae
- highly modified morphology for burrowing
- python-like
- vestiges of pelvic girdle and hind limb bones
Specimens on display:
Loxocemus bicolor
Tropidophiidae
No specimens available
Xenopeltidae
No specimens available
Acrochordidae
No specimens available
Colubridae
- very diverse in morphology
- scales on top of head behind eyes are enlarged
- chin shields enlarged
- ventral scales in single row
- some are rear-fanged and venomous
- most subfamilies difficult to distinguish by external morphology
Homolopsinae:
- adapted for aquatic life: eyes directed upward, valvular nostrils
- rear-fanged
- Herpeton tentaculum has two tentacles projecting from snout
Xenodontinae:
- many have enlarged rear teeth
Colubrinae:
- generalized morphology
Specimens on display:
Natricinae:
Nerodia cyclopion
Nerodia erythrogaster
Nerodia fasciata
Nerodia sipedon
Rhabdophis (Natrix) tigrinus
Storeria dekayi
Storeria occipitomaculata
Thamnophis sauritus
Thamnophis sirtalis
Xenochrophis (Natrix) piscator
Homolopsinae:
Erpeton (Herpeton) tentaculum
Xenodontinae:
Alsophis portoricensis
Carphophis amoenus
Cleilia cleilia
Diadophis punctatus
Farancia abacura
Heterodon platyrhinos
Liophis poecilogyrus
Liophis sagittifer
Lystrophis semicinctus
Colubrinae and other colubrids:
Ahaetulla (Dryophis) nasuta
Ahaetulla tristis
Arizona elegans
Boiga multomaculata
Chironactis occipitalis
Chironius fuscus
Chironius grandisquamis (melas)
Chironius quadricarinatus
Coluber constrictor
Coniophanes andresensis
Dinodon rufozonatum
Eirenis collaris
Elaphe guttata
Elaphe obsoleta
Elaphe schrenckii
Enuliophis (Enulius) sclateri
Gastopyxis smaragdina
Lampropeltis calligaster
Lampropeltis triangulum
Lampropeltis zonata
Lamprophis (Boaedon) fuliginosus
Lamprophis (Boaedon) virgatus
Leptodeira septentrionalis
Leptophis (Aetophis) ahetulla
Masticophis flagellum
Opheodrys vernalis
Oxybelis aeneus
Pareas (Amplycaphalus) margaritophorus
Pituophis melanoleucus
Rhinocheilus lecontei
Tropidodipsas sartori
Elapidae
- diverse in morphology
- short, permanently erect fangs
- in derived species most teeth have been lost from maxilla
- scales on top of head behind eyes enlarged
- chin shields enlarged
- ventral scales in single row
Hydrophiinae: sea snakes
- flattened tails, body laterally compressed
- reduced eye size
- valvular nostrils
- ventral scales in two rows
Specimens on display:
Bungarus sp.
Dendroaspis polylepis
Micrurus frontalis
Micrurus fulvius
Naja melanoleuca
Naja naja
Hydrophiinae:
Enhydrina sp.
Hydrophis sp.
Pelamis platurus
Pseudonaja (Demansia) textilis
Viperidae
- long fangs at the front of the mouth that can be folded backward
- large venom glands with associated muscles located at back of head, give head triangular shape
- crotalines have loreal heat-sensitive pits between eye and nostril, absent in viperines
- Crotalus and Sistrurus have rattles on tails
Specimens on display:
Viperinae:
Bitis nasicornis
Causus rhombeatus
Daboia (Viperia) russelli
Echis sp.
Crotalinae:
Agkistrodon contortrix
Agkistrodon piscivorus
Bothriechis (Bothrops) schlegeli
Bothrops atrox
Crotalus adamateus
Crotalus atrox
Crotalus cerastes
Crotalus durissus
Crotalus horridus
Porthidium (Bothrops) nasutum
Sistrurus miliarius
Scolecophidia
Anomalepidae
Leptotyphlopidae
Typhlopidae
Alethinophidia
Aniloidea
Aniliidae
Uropeltidae
Macrostomata
Boidae
Boyleriidae
Loxocemidae
Tropidophiidae
Xenopeltidae
Caenophidia
Acrochordidae
Colubroidea
Colubridae
Elapidae
Viperidae
Atractaspidae
Anomalepidae
No specimens available
Leptotyphlopidae
- small, burrowing snakes, thin bodies
- eyes vestigial, lack brille, covered by scales
- retain vestiges of pelvic girdle, sometimes as horny projections
- no gastrosteges
- ventral scales transversely elongated
- 14 scale rows at midbody
Specimens on display:
Leptotyphlops sp.
Leptotyphlops conjunctus
Leptotyphlops distanti
Leptotyphlops goudotii
Leptotyphlops phenops
Typhlopidae
- small, blind, burrowing snakes
- similar to typhlopids
- sharp snout, distinct rostral shield for burrowing
- retain vestiges of pelvic girdle
- eyes covered by scales
- ventral scales transversely elongated
- 20 scale rows at midbody
Specimens on display:
Typhlops sp.
Typhlops richardi
Aniliidae
No specimens available
Uropeltidae
- burrowing snakes
- no vestigial pelvic bones or limbs
- eyes reduced, lack brille
- gastrosteges reduced or absent
- tip of tail with enlarged, rigid scale with two points or circular area covered with thick, spiny scales
Specimens on display:
Uropeltis sp.
Boidae
- retain vestiges of pelvic girdle and hind limb bones
- gastrosteges narrower than colubrids
- pythons have premaxillary teeth, boas do not
- some with heat-sensitive pits on labial scales
- scales on top of head behind eyes small
- chin shields not enlarged
Boinae: no premaxillary teeth
Erycinae: wedge-shaped head, some with pronounced canthus rostralis
Pythoninae: premaxillary teeth present
Specimens on display:
Boinae
Charina (Lichanura) trivirgata
Charina bottae
Corallus (Boa) caninus
Corallus (Enhydris) cookii
Epicrates cenchria
Erycinae
Calabaria reinhardtii
Gongylophis (Eryx) conicus
Pythoninae
Morelia spilota
Morelia viridis
Python regius
Boyleriidae
No specimens available
Loxocemidae
- highly modified morphology for burrowing
- python-like
- vestiges of pelvic girdle and hind limb bones
Specimens on display:
Loxocemus bicolor
Tropidophiidae
No specimens available
Xenopeltidae
No specimens available
Acrochordidae
No specimens available
Colubridae
- very diverse in morphology
- scales on top of head behind eyes are enlarged
- chin shields enlarged
- ventral scales in single row
- some are rear-fanged and venomous
- most subfamilies difficult to distinguish by external morphology
Homolopsinae:
- adapted for aquatic life: eyes directed upward, valvular nostrils
- rear-fanged
- Herpeton tentaculum has two tentacles projecting from snout
Xenodontinae:
- many have enlarged rear teeth
Colubrinae:
- generalized morphology
Specimens on display:
Natricinae:
Nerodia cyclopion
Nerodia erythrogaster
Nerodia fasciata
Nerodia sipedon
Rhabdophis (Natrix) tigrinus
Storeria dekayi
Storeria occipitomaculata
Thamnophis sauritus
Thamnophis sirtalis
Xenochrophis (Natrix) piscator
Homolopsinae:
Erpeton (Herpeton) tentaculum
Xenodontinae:
Alsophis portoricensis
Carphophis amoenus
Cleilia cleilia
Diadophis punctatus
Farancia abacura
Heterodon platyrhinos
Liophis poecilogyrus
Liophis sagittifer
Lystrophis semicinctus
Colubrinae and other colubrids:
Ahaetulla (Dryophis) nasuta
Ahaetulla tristis
Arizona elegans
Boiga multomaculata
Chironactis occipitalis
Chironius fuscus
Chironius grandisquamis (melas)
Chironius quadricarinatus
Coluber constrictor
Coniophanes andresensis
Dinodon rufozonatum
Eirenis collaris
Elaphe guttata
Elaphe obsoleta
Elaphe schrenckii
Enuliophis (Enulius) sclateri
Gastopyxis smaragdina
Lampropeltis calligaster
Lampropeltis triangulum
Lampropeltis zonata
Lamprophis (Boaedon) fuliginosus
Lamprophis (Boaedon) virgatus
Leptodeira septentrionalis
Leptophis (Aetophis) ahetulla
Masticophis flagellum
Opheodrys vernalis
Oxybelis aeneus
Pareas (Amplycaphalus) margaritophorus
Pituophis melanoleucus
Rhinocheilus lecontei
Tropidodipsas sartori
Elapidae
- diverse in morphology
- short, permanently erect fangs
- in derived species most teeth have been lost from maxilla
- scales on top of head behind eyes enlarged
- chin shields enlarged
- ventral scales in single row
Hydrophiinae: sea snakes
- flattened tails, body laterally compressed
- reduced eye size
- valvular nostrils
- ventral scales in two rows
Specimens on display:
Bungarus sp.
Dendroaspis polylepis
Micrurus frontalis
Micrurus fulvius
Naja melanoleuca
Naja naja
Hydrophiinae:
Enhydrina sp.
Hydrophis sp.
Pelamis platurus
Pseudonaja (Demansia) textilis
Viperidae
- long fangs at the front of the mouth that can be folded backward
- large venom glands with associated muscles located at back of head, give head triangular shape
- crotalines have loreal heat-sensitive pits between eye and nostril, absent in viperines
- Crotalus and Sistrurus have rattles on tails
Specimens on display:
Viperinae:
Bitis nasicornis
Causus rhombeatus
Daboia (Viperia) russelli
Echis sp.
Crotalinae:
Agkistrodon contortrix
Agkistrodon piscivorus
Bothriechis (Bothrops) schlegeli
Bothrops atrox
Crotalus adamateus
Crotalus atrox
Crotalus cerastes
Crotalus durissus
Crotalus horridus
Porthidium (Bothrops) nasutum
Sistrurus miliarius
Snakes of Connecticut
Colubridae
Colubrinae
Coluber constrictor
Elaphe obsoleta
Lampropeltis triangulum
Opheodrys vernalis
Natricinae
Nerodia sipedon
Storeria dekayi
Storeria occipitomaculata
Thamnophis sauritus
Thamnophis sirtalis
Xenodontinae
Carphophis amoenus
Diadophis punctatus
Heterodon platyrhinos
Viperidae
Agkistrodon contortrix
Crotalus horridus
Carphophis amoenus (Eastern worm snake)
Family Colubridae (Xenodontinae)
Morphological characteristics:
- small, adapted for fossorial life
- reduced eyes, narrow head
- tail short and sharply pointed
- 13 dorsal scale rows
- dorsal scales smooth
- anal plate divided
Living specimens:
- pinkish-brown in color
Coluber constrictor (Black racer)
Family Colubridae (Colubrinae)
Morphological characteristics:
- long and slender
- rounded in cross-section (Elaphe obsoleta like loaf of bread in cross-section)
- scales smooth (scales in Elaphe obsoleta are keeled)
- 15 dorsal scale rows at posterior end of body
- anal plate divided
- usually 7 upper labial scales
Living specimens:
- glossy black on dorsal surface, dark gray or black on venter
- chin and underside of neck are yellowish-white (Elaphe obsoleta has pure white chin)
Diadophis punctatus (Northern ringneck snake)
Family Colubridae (Xenodontinae)
Morphological characteristics:
- small and slender
- scales smooth and glossy
- nasal plate divided
- anal plate divided
Living specimens:
- yellow or orange neck band
- dark gray or black head and dorsum
- bright yellow or orange venter
Elaphe obsoleta (Black rat snake)
Family Colubridae (Colubrinae)
Morphological characteristics:
- rough scales with weak keels (Coluber constrictor has smooth scales)
- heavier body than Coluber constrictor
- shaped like loaf of bread in cross section
- <30 dorsal scale rows
- anal plate divided
- 8 upper labial scales
Living specimens:
- solid black in color, white chin
- juveniles purplish gray with dark blotches
Heterodon platyrhinos (Eastern hognose snake)
Family Colubridae (Xenodontinae)
Morphological characteristics:
- upturned, hard snout
- rostral scale turned upward and keeled
- stocky body
- scales keeled
- anal plate divided
Living specimens:
- pattern and coloration variable: some mottled with background of yellow, brown, or red; others almost black
- venter mottled gray
Lampropeltis triangulum (Eastern milk snake)
Family Colubridae (Colubrinae)
Morphological characteristics:
- scales smooth
- usually 21 dorsal scale rows
- dorsal scales smooth
- anal plate not divided
Living specimens:
- adults with red or brown blotches edged in black on purple or gray background
- juveniles more reddish than adults
Nerodia sipedon (Northern water snake)
Colubridae (Natricinae)
Morphological characteristics:
- relatively heavy-bodied with rough, keeled scales
- does not have the triangular head characteristic of Agkistrodon contortrix
- 21+ dorsal scale rows
- anal plate divided
Living specimens:
- pattern variable, generally brown with bands across body
- markings distinct as juveniles, darken into uniform brown with age
Opheodrys vernalis (Smooth green snake)
Family Colubridae (Colubrinae)
Morphological characteristics:
- no keels on scales
- 17 dorsal scale rows
- anal plate divided
Living specimens:
- solid green in color, venter yellow or white
Storeria dekayi (Dekay’s snake, northern brown snake)
Family Colubridae (Natricinae)
Morphological characteristics:
- small and slender
- scales are keeled
- usually 17 dorsal scale rows
- anal plate divided
- 7 upper labial scales
- 1 preocular scale
Living specimens:
- nondescript and brown in color
- dorsum dull brown or tan, lighter vertebral band bordered by rows of black spots
- venter greenish to grayish white
- sides of head light
- distinct dark spot between each eye
- dark spot on neck
Storeria occipitomaculata (Red-bellied snake)
Family Colubridae (Natricinae)
Morphological characteristics:
- scales keeled
- anal plate divided
- 15 dorsal scale rows
- 6 upper labial scales
- two preocular scales
Living specimens:
- bright red venter
- light spots in occipital region behind head
- dorsal color gray or black
Thamnophis sauritus (Eastern ribbon snake)
Family Colubridae (Natricinae)
Morphological characteristics:
- long and slender
- tail long in proportion to rest of body
- < 27 dorsal scale rows
- 7 upper labial scales
- scales keeled
- anal plate not divided
Living specimens:
- three distinct yellow stripes on dark background
- lateral stripes on scale rows 3 & 4
- dark stripe below lateral yellow stripe on each side
Thamnophis sirtalis (Eastern garter snake)
Family Colubridae (Natricinae)
Morphological characteristics:
- compared to T. sauritus, tail shorter in proportion to body
- < 27 dorsal scale rows
- scales keeled
- anal plate not divided
- 7 upper labial scales
Living specimens:
- less distinct stripes than T. sauritus
- can be spotted or striped
- lateral stripes on scale rows 2 & 3
Agkistrodon contortrix (Northern copperhead)
Family Viperidae (Crotalinae)
Morphological characteristics:
- triangular head shape
- heat-sensing pit
- stocky body
- tail pointed without rattle
- scales weakly keeled
- anal plate not divided
Living specimens:
- coppery color
- hourglass-shaped bands across back
Crotalus horridus (Timber rattlesnake)
Family Viperidae (Crotalinae)
Morphological characteristics:
- triangular head shape
- heat-sensing pit
- stocky body
- rattle
- scales distinctly keeled
- area between eyes with small scales
Living specimens:
- two color phases: yellowish with dark brown or black bands or nearly all black with indistinct bands
- tail black
