Poisonous snakes are found throughout the world,
with the exception of certain islands and the Antarctic.
There are five venomous families of snakes.
Viperidaeincludes rattlesnakes, moccasins,
South American lance-headed vipers and
bushmaster, Asian pit vipers, African and Asian
vipers and adders, the European adder, and
saw-scaled viper (Middle-eastern). Kills mainly
by coagulopathy (a blood clotting disorder) and
ElapidaeIncludes cobras, kraits, mambas, and
coral snakes. Kills from neurotoxic venom that
can cause respiratory failure, paralysis, and
HydrophidaeIncludes sea snakes and
venomous snakes from the islands of the
southern Pacific Ocean, including Australia,
New Zealand, and New Guinea. Also kills from
ColubridaeIncludes most of the common
nonvenomous species, as well as the boomslang,
and vine/twig/bird snake (Africa); Japanese
yamakagashi; Southeast Asian red-necked
callback. Venoms method of toxic action varies
according to type of snake.
AtractaspididaeIncludes the burrowing
asps/mole vipers, stiletto snakes, and adders.
Venoms method of toxic action varies
according to type of snake.
Within the United States, poisonous snakes are
Crotalids (rattlesnakes, copperheads, and moccasins)
and the Elapids (coral snakes).
CROTALIDS.Crotalids are of the Viperidae
(viper) family and are called pit vipers because of the
small, deep pits between the nostrils and the eyes (fig.
5-3). They have two long, hollow fangs. These fangs are
normally folded against the roof of the mouth, but they
can be extended when the snake strikes. Other
identifying features of the Crotalids include thick bodies;
slit-like pupils of the eyes; and flat, triangular heads. The
most identifying feature of a pit viper is the relative width
of the snakes head compared to the thickness of the body.
The head will be much wider than the body, giving the
appearance of an arrowhead. The difference in size is so
obvious that identification of a snake as a pit viper can
usually be made from a safe distance.
Further identification can be made by examining
the wound for signs of fang entry in the bite pattern. Pit
viper bites leave two puncture marks (sometimes only
one, and sometimes more). Nonvenomous snakes (for
example, garter snakes) leave a series, often in a curve
or semi-circle, of tiny scratches or punctures.
Individual identifying characteristics include rattles
on the tails of most rattlesnakes, and the cotton-white
interior of the mouths of moccasins.
ELAPIDS.Coral snakes are of the family
Elipidae and related to the cobra, kraits, and mamba
snakes in other parts of the world (fig. 5-4). Corals,
which are found in the Southeastern United States, are
comparatively thin snakes with small bands of red,
black, and yellow (or almost white).
Figure 5-3.American pit vipers.