The boa constrictor is a species of large, non-venomous, heavy-bodied snake.
It is an exclusively New World species which has the largest distribution of all neotropical boas.
Boa constrictors range from northern Mexico south through Central and South America.
They live 20-30 years in the wild.
Boa constrictors range in length from 50 centimeters (50 centimeters) as newborns, or neonates, to 3.9 meters (13 feet) as adults. They can weigh more than 45 kilograms (100 pounds) when full grown.
They wear some of the most distinctive markings of all reptiles. Depending on the habitat they are trying to blend into, their bodies can be tan, green, red, or yellow, and display cryptic patterns of jagged lines, ovals, diamonds, and circles.
Their teeth are small and hooked, which allows for a strong grip when the snake strikes its prey and prevents the prey from wiggling free while the snake wraps its powerful body around the victim. It is commonly believed that boa constrictors subdue their prey by crushing their bones or squeezing their lungs to suffocate them, but recent research on the constriction method revealed that these snakes employ a different strategy all together.
Once the snake has its body wrapped around the prey, it squeezes just enough to cause a “circulatory arrest” by cutting off the ability of the heart to pump blood in and out. By keeping blood from flowing to the brain, the animal dies.
Boa constrictors generally live on their own and do not interact with any other snakes unless they want to mate.
They are nocturnal, but they may bask during the day when night-time temperatures are too low.
As semi-arboreal snakes, young boa constrictors may climb into trees and shrubs to forage – however, they become mostly terrestrial as they become older and heavier.
Their prey includes a wide variety of small to medium-sized mammals and birds. The bulk of their diet consists of rodents, but larger lizards and mammals as big as ocelots are also reported to have been consumed. Boa constrictors also like to eat bats! They catch them by hanging from tree branches or the mouth of caves and knocking the bats out of the air as they fly by.
It takes the snake about 4–6 days to fully digest the food, depending on the size of the prey and the local temperature. After this, the snake may not eat for a week to several months, due to its slow metabolism.
Like all snakes, boa constrictors in a shed cycle are more unpredictable, because the substance that lubricates between the old skin and the new makes their eyes appear milky, blue, or opaque so that the snake cannot see very well, causing it to be more defensive than it might otherwise be.
Boa constrictors are ovoviviparous, giving birth to live young. The average litter has 25 young but can be anywhere from 10 to 64 young.
Young boa constrictors eat small mice, birds, bats, lizards, and amphibians. The size of the prey item increases as they get older and larger.
This species does well in captivity, usually becoming quite tame. It is a common sight in both zoos and private reptile collections.
Though still exported from their native South America in significant numbers, they are widely bred in captivity.
When kept in captivity, they are fed mice, rats, rabbits, chickens, and chicks depending on the size and age of the individual.
Captive life expectancy is 20 to 30 years, with rare accounts over 40 years, making them a long-term commitment as a pet.
Boa constrictors like many other large snakes, are killed for their skins, which are highly prized in the leather trade. These snakes are not farmed for their skins, and collecting them from the wild has caused population declines.
They are also consumed by indigenous people and collected for the pet trade. They have long been popular as pets because of their large size and relatively calm demeanor.
Probably their biggest threats are the ever-increasing human populations and the loss of prime habitat. Boas are very important in controlling rodent populations which, when in excess, can have a seriously negative impact on the environment.
Though all boids are constrictors, only this species is properly referred to as a “boa constrictor” – a rare instance of an animal having the same common English name and scientific binomial name.
Nine subspecies are currently recognized, although some of these are controversial.