Location at the Zoo:
Region: South and Central America
Boa constrictorBoa constrictor coloration and pattern are distinctive. Dorsally the background color is cream or brown and that is marked with dark "saddle-shaped" bands. These saddles become more colorful and prominent towards the tail, often becoming reddish brown with either black or cream edging. Along the sides, there are rhomboid, dark marks. They may have smaller dark spots over the entire body. The head of a boa constrictor has three distinctive stripes. First is a line that runs dorsally from the snout to the back of the head. Second, there is a dark triangle between the snout and the eye. Third, this dark triangle is continued behind the eye, where it slants downward towards the jaw. However, there are many variations on appearance. Boas have two functional lungs, the right much larger than the left, to match their elongated body shape. Sharp, long teeth are found on both the upper and lower jaws and curve backward towards the throat.
This new world snake has an average length of two to three metres while the largest ever recorded was 5.5 m. Sexual dimorphism (difference between males and females) includes females generally being larger in body length and girth, whereas males generally have longer tails (containing the hemipenes) and longer cloacal spurs (vestigal hind legs).
Conservation Status: IUCN
Distribution:Boa constrictors range from northern Mexico south through Central and South America. In South America the range splits along the Andes mountains. To the east of the Andes, they are found as far south as northern Argentina. On the west side of the mountains, the range extends into Peru. Boa constrictors are also found on numerous islands off the Pacific coast and in the Caribbean. Islands included in the boa constrictor range are: the Lesser Antilles, Trinidad, Tobago, Dominica, and St. Lucia. Some islands off the coast of Belize and Honduras are also inhabited by this species.
Habitat:Ranges from tropical rain forest to semi-desert. In Mexico it is found in semi-arid regions, on the fringes of deserts. In tropical America it is found in the dense, wet jungles (rarely entering water). They spend much of their time in trees but are also found near cultivated land and plantations. They will enter villages in search of food.
Diet:Prey items include large lizards, birds, and small mammals (bats, monkeys, squirrels, opposums, rats, pacas, agoutis and wild pigs). There have been occasions where fairly large animals have been taken. Those boas entering villages would take rodents and chickens.
Reproduction:Seasonal changes trigger breeding behaviour. This generally takes place in the dry season. During this period the female emits a scent from her cloaca. Females do not necessarily reproduce annually. Boa constrictors are ovoviviparous; embryos develop within their mothers' bodies. This places a great physical demand on females and a period of recovery is needed after the birthing process to restore fat reserves.
Males are polygynous, mating with more than one female. Boas are considered to be primitive snakes. Both the male and female have a pair of spurs, one on either side of the cloaca. The male's spurs are longer than the female's. He uses them to stimulate the female by scratching her body, especially around the cloaca. When ready to mate, the male inserts one of his two hemipenes into the female's cloaca. Fertilized ova are retained in the female's body for incubation. Young are born live (ovoviviparous). Up to 60 young are born, about 30-40 cm at birth. They are independent soon after birth.