The Boa Constrictor is found extensively throughout Mexico and South America.
Non-venomous, kills by constriction, mainly arboreal, but also moves freely on the ground. It has pelvic spurs, which are remnants of hind legs on either side of the cloacal opening. They are larger in males than in females. Males possess a hemipenis, a double penis, only one of which is used in mating.
It is a solitary snake and associates with fellow snakes only for mating. They are nocturnal or crepuscular, although they bask in the sun to warm themselves in cold weather. It reproduces ovoviviparously, the embryos develop in the egg inside the body of their mothers. The young are born alive and are independent soon after birth. They generally breed during the dry season and gestation lasts from 5 to 8 months depending on local temperatures. They produce an average of 25 offspring.
Threats include being hunted for their skin and meat, loss of their habitat and capture for commercial trade.