The best known of the boas family, non-venomous snakes that incapacitate their victims by wrapping themselves around their bodies.
Although they appear dangerous, they pose little threat to humans. The most common injuries they inflict on humans are bites, which are painful but not life threatening.
They are popular with breeders because of their interesting appearance. A few decades ago, most Boa constrictors were captured from the wild; fortunately, most commercially available Boa constrictors today are bred.
Boas are a family of 49 species divided into 12 genera. The first constrictors appeared on Earth at the end of the Cretaceous period, about 70.5 million years ago.
They are encountered on the territory of Argentina, Brazil, Bolivia, Ecuador, Colombia, Guyana, French Guiana, Peru, Trinidad and Tobago, Uruguay and Venezuela.
Boa constrictors also live in southern Florida, however, the snakes have been introduced there by humans.
However, they strongly prefer forested areas that are rich in food, full of hiding places, and sufficiently moist and warm. Boas often live in the burrows of medium-sized mammals, which provide them with protection from potential predators.
During the day, however, they can be found basking in the sun for energy.
After dark, they go out in search of food, where they find a hiding place to lurk for approaching prey and attack by surprise.
They spend most of their time on the ground, although they can climb and are sometimes found in trees.
Their diet consists mainly of birds and small and medium-sized mammals. Although their prey is usually rodent-sized, they are capable of taking down prey up to 50 cm in length. Juveniles often hunt amphibians, lizards, mice, small birds and bats due to their size.
Only when the victim dies does the boa continue to eat, consuming its prey whole. Contrary to what the name of these animals may imply, the victims are most often killed by blocking the circulation to major body organs such as the brain and heart, rather than by strangulation.
They can often be found in the vicinity of rivers and streams.
Their skin color is made up of patches of brown, gray, and cream. The dark brown patches are less pronounced near the head and become more intense the closer they are to the tail.
The average size of females varies between 2.1 and 3 meters and males between 1.8 and 2.4 meters.
Females weigh between 10 and 15 kg. The largest boa constrictors exceed 45 kilograms.
The left lung is smaller and unused for breathing, which is done exclusively by the right lung. This is a rather unusual feature among snakes, as most colubrids have completely lost their left lung.
It is the female who chooses her mate, first by attracting him with pheromones and then by fighting and assessing his ability to procreate. Copulation can last from a few minutes to a few hours, and the sperm deposited by the male can remain in the female's body for up to a year.
There can be anywhere from 10 to 65 young (25 on average), some of which are unhatched or unfertilized eggs. Young Boa constrictors are between 38 and 51 cm long at birth.
The vast majority of these snakes reproduce sexually, although hermaphroditic reproduction has been observed.
Reaching sexual maturity does not stop growth. Boas continue to grow throughout their lives, although at a slower rate than during the juvenile stage.
They are not common in the wild, but are popular with breeders who cross them with other individuals to create new color varieties.
Most often, boa constrictors fall prey to eagles, hawks, alligators and caimans, as well as humans.
Its population has declined only in some areas where it is captured for trade or killed by predators. It is considered an invasive species in Florida.