Identification
This is relevant for all animals belonging to Terrestrial Snakes in North America.
Snake not available
Distribution
See Geographical Distribution to narrow down the possible culprits on country/state level.
Biological Features
North America
Description of the most important representatives:
| General behaviour | Habitats | Appearance | Defensive behaviour | Factors relevant to envenoming | |
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Micrurus sp. and Micruroides euryxanthus
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primarily nocturnal, but also seen during the day ground-dwelling |
stony and sandy arid areas |
conspicuous warning colouring consisting of black, red and yellow (or beige, or white)cross bands (a number of harmless colubrids also have this colouring, but in Micrurus the red and yellow bands are adjacent, while in colubrids the red and black rings are adjacent) |
when threatened, the end of the tail is raised in the air and moved back and forth; the head is sometimes hidden under the coils of the body |
generally non-aggressive behaviour; only rarely the cause of snakebites |
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nocturnal in warm weather, diurnal in cool ground-dwelling |
A. contortrix primarily in deciduous forests, A. piscivorus is a semi-aquatic species found in bodies of water or swamps |
sturdy body; A. piscivorus up to 1.8 m long |
A. piscivorus does not try to flee when threatened; head is thrown back and mouth is opened wide, so that the white interior of the mouth becomes visible; vibration of the tip of the tail |
A. contortrix is the most common cause of venomous snakebites in the USA; A. piscivorus bites common in the Mississippi valley and along the Gulf Coast of the USA |
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nocturnal in warm weather, diurnal in cool ground-dwelling |
primarily in arid areas, from the lowlands to mountains. C. horridus in wooded regions and swamps |
stout body with characteristic rattle on the end of the tail; smaller species around 60 cm, the largest up to 1.5 m long |
a typical dry and high warning sound is produced by vibration of the rattle; during this process the body is formed into a tightly coiled S-shape |
accidents common in the USA; these are often self-inflicted, i.e. the result of unnecessary handling of these snakes; men are most common victims |
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primarily nocturnal, but also seen during the day ground-dwelling |
S. miliarius in dry habitats, S. catenatus in damper habitats |
as for Crotalus sp., but on average smaller (<1 m); also have a rattle |
as for Crotalus sp. |
accidents less common than with Crotalus sp. |
Snake available
Morphological Identification
Morphological key to the terrestrial venomous snakes
| Only ever pick up dead snakes! Caution - reflex bites are possible in snakes that have only just been killed. Hold the snake with one hand behind the head, and with the other hand open the mouth using tweezers and observe the dentition (also look for teeth that may be hidden in mucosal folds). | ||||
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Are all the teeth +/- of the same size? | yes |
Harmless snakes (local symptoms may occur) |
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| no
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Enlarged teeth (venom fangs, generally grooved at the front or with a venom duct orifice near the tip) are +/- at the back; there are always normal teeth in front of these venom fangs! | yes |
some species of Colubridae |
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| no
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Venom fangs are at the very front of the row of teeth and are +/- fixed (not moveable) in the upper jaw. May be so small as to be barely visible! | yes
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Elapidae (no Elapidae in Europe!) » proceed to regional identification |
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| no
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| Exceedingly long venom fangs at the very front of the upper jaw that can be erected forwards, in rare cases laterally. Normally they are folded back and covered by mucosal sheaths! | ||||
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Is there a pit between the nostril and the eye? | yes
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Crotalinae (no Crotalinae in Central and Southern Africa, and Australia!) » proceed to regional identification |
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| no | ||||
| Viperinae (no Viperinae in the Americas and Australia!) | ||||