Over 30 boa species are found from Mexico to South America, with the greatest variey in the tropics, and two in the United States. Boas may be terrestrial, arboreal, or burrowing. Some are brightly colored, like the green and white emerald tree boa of the tropics (Boa canina), or iridescent, like the wide-ranging rainbow boa (Epicrates cenchris). Best known is the boa constrictor (Constrictor constrictor), which lives in a variety of terrestrial habitats from S Mexico to central Argentina. It averages 6 to 9 ft (1.8–2.7 m) in length, occasionally reaching 14 ft (4.3 m), and has dark brown diamond markings on a lighter background. The South American anaconda (Eunectes murinus) is a semiaquatic boa that inhabits swamps and river shallows, catching animals that come to drink. The longest member of the boa family and the thickest of all snakes, it may reach 25 ft (7.9 m) in length and 3 ft (90 cm) in girth. The rubber boa (Charina bottae) is found in moist regions of the far W United States and extreme SW Canada. It is a burrower, about 18 in. (46 cm) long, with a narrow, blunt head, broad, blunt tail, and silver-green skin. It feeds chiefly on lizards and rodents. The rosy boa (Lichanura roseofusca) is found in chaparral in the SW United States and N Mexico; it grows about 3 ft (90 cm) long. It has large, dark brown spots on a lighter background. Several species of sand boa (Eryx) are distributed from India and central Asia to N Africa and SE Europe; all are burrowers in sand. There are also several boa species on Madagascar and several on Pacific islands.
Boas are classified in the phylum Chordata, subphylum Vertebrata, class Reptilia, order Squamata, family Boidae.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2023, Columbia University Press. All rights reserved.
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