Boa Snakes

Boa is the common name for about
6 genera and 50 species of SNAKES that
constitute the family Boidae. Closely related to
PYTHONS, the family includes the largest of all
snakes, the water-dwelling ANACONDA of
South America. Among other boas are the smaller
sand boas, Eryx, and the woodsnakes,
Tropidolphus and related genera. The typical boa
genera are ground or tree dwellers of tropical
America--as are the woodsnakes--and the island
of Madagascar, whereas the sand boas are
semidesert burrowing snakes of northern Africa
and southern Asia. The two North American
boas--the rosy and the rubber boa--resemble the
sand boas. All boas are nonpoisonous and kill by
constriction; unlike the pythons, they bear live
young. They are primitive snakes with anatomical
features that reflect their lizard ancestry, such as
bony vestiges of hind limbs that terminate in
external claws, and the presence--except in the
woodsnakes--of two functional lungs. Most boas
are active at night and have pits along their lips that
are sensitive to the heat of prey. The snakes are
usually handsomely marked and often iridescent,
the most striking being the rainbow boa, Epicrates
cenchis. The species best known as "boa" is the
boa constrictor, Constrictor constrictor, which
ranges from Mexico to Argentina and the West
Indies. The snake grows up to 3.7 m (12 ft) long,
but a 5.6-m (18.5-ft) specimen is on record.
Picture Caption[s] The boa constrictor, C.
constrictor, is a New World snake that grows up
to 3.7 m (12 ft) long. It kills rodents and other
small animals by striking and coiling around its
victim with incredibly fast movements. Once
wrapped around its prey, the boa constrictor
tightens its coils, preventing the animal from
breathing. It then swallows its meal whole.

Category: Science