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Boa Constrictor

Boa constrictor


The boa constrictor is a relatively small member of the Boidae family, being on average about 13 feet long and weighing about 60 pounds when fully grown; the largest boa constrictor ever recorded was 18 feet long. The coloration and markings of this species are distinctive, although there is some variation according to specific habitat. The background color is cream or brown, and the dorsal side is marked with dark "saddle-shaped" bands that become more colorful and prominent towards the tail. The sides bear dark rhomboid-shaped markings.

boa constrictor

The most distinctive feature is the head (seen below), which has a dark stripe running dorsally from the snout to the back of the head, a dark triangle between the snout and eyes, and a continuation of that triangle behind each eye that slants downward towards the jaw. The mouth is lined with small, hooked teeth that are used for grabbing and holding prey.

head of the boa constrictor

Distribution and Habitat

Boa constrictors are found from northern Mexico to Peru and Argentina, as well as on several offshore islands. They live in a variety of habitats, from semi-arid and desert to wet tropical jungles and including open savanna and cultivated fields.

distribution of the boa constrictor


Boa constrictors will eat just about anything they can catch and swallow, including lizards, birds, monkeys, and wild pigs, but have a special preference for bats. They are ambush predators, and kill by wrapping their body around the prey and squeezing until suffocation occurs.


The breeding season runs from April to August, depending on climatic conditions. Females seldom mate more than once every other year, while males may mate every year. The young (20-60 per brood) are born live after a gestation period of five to eight months, and are independent almost immediately after birth. About 20 inches long at birth, the young are miniature versions of adults in coloration and markings. They are sexually mature at about two-and-a-half years. Boa constrictors can live up to 30 years in the wild.

Other Habits and Behaviors

Boa constrictors are solitary and nocturnal. Although they are excellent swimmers they are seldom found in the water. They readily take to trees, and can often be seen lurking on the end of a branch waiting for a bat to fly by and provide a meal.

Scientific Classification

phylum Chordata
subphylum Vertebrata
class Reptilia
order Squamata
suborder Serpentes
family Boidae
subfamily Boinae
genus & species Boa constrictor

Animal Diversity Web

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This page was last updated on November 06, 2017.