d. Family Hydrophidae. There are approximately 100 species in this family.
The words "adder" and "viper" are commonly used in literature and in a few areas of the
world. "Adder" may be used to described nonvenomous snakes (i.e., hognose and milk
snake in North America). These snakes can be found in Southeast Asia, the southwest
Pacific Islands and one species reaches the western coasts of tropical America. They
have short fangs and the venoms act primarily on skeletal muscle. The venom of these
snakes is often extremely potent but small in quantity.
e. Family Crotalidae. There are approximately 100 species of Crotalidae.
Many are pit vipers. The best-known pit vipers are the rattlesnakes. Rattlesnakes are
found in North, South, and Central America and all of them are venomous. With the
exception of Crotalus catalinensis, all rattlesnakes have rattles. They are relatively
heavy bodied, have broad heads and are marked with blotches or cross bands over the
back. In addition to the rattlesnake, some common names of snakes in the family.
Crotalidae are moccasins, new world pit vipers, bushmasters, massasaugas and pygmy
rattlesnakes. There is also the Asiatic pit viper found in Asia. These snakes have
single large fangs on short and their otherwise toothless maxillae rotate which permits
the fangs to be erected or folded against the roof of the mouth (hinged). The venom
usually causes local necrosis and hemorrhage.
f. Family Viperinae. There are approximately 50 species in this family. These
snakes can be found in Africa, Asia, and Europe. They have large hinged fangs and the
venom is extremely necrotic and hemorrhagic. One of the deadliest members of this
family is the Gaboon viper.
GENERAL CHARACTERISTICS OF U.S. CROTALINAE
Rattlesnakes, moccasins, and copperheads are classified as pit vipers. They
have large fangs and deeply inject a large amount of venom. The name "pit viper" is
derived from the deep pit between the eye and nostril on each side of the head. Inside
this pit is a sensory organ that is capable of detecting small amounts of radiant heat.
The pit viper's head is flat and triangular-shaped and is very distinct from its neck; its
eyes have a cat-like pupil and are elliptical; and it has a thick, stout body with a thin
INDIVIDUAL CHARACTERISTICS OF U.S. CROTALINAE
a. Rattlesnake (Crotalus). There are some 51 species of the rattlesnake
(Figure 1-4) that can be found in every state of the continental U.S., with the exception
of Maine. This snake lives in dry desert areas, grassy plains, forests, and in rocky
areas. One can easily identify this snake due to the audible rattles at the end of the tail;
however, one species found in an island off southern California is called the "rattleless"
rattlesnake because it has no rattle. Rattlesnakes grow to a length of two to eight feet.
The color and markings vary according to the species and the region where it is found.
However, three or more species may be found in the same locale in parts of Texas,
New Mexico, Arizona, and California. In these areas, identification may be difficult.