The Boa constrictor is a fairly large snake. There is clear sexual dimorphism seen in the species with females generally being significantly larger, in both length and girth, than males. Boa constrictors can sense heat via cells in their lips. They have two lungs, a smaller (non-functional) left and enlarged (functional) right lung to better fit their elongated shape, unlike many snakes which have completely lost the left lung. Boa constrictors are solitary animals, and will only associate to mate. They are nocturnal; however, they may bask during the day when night-time temperatures are too low. Young boa constrictor may climb into trees and shrubs to forage, however they become mostly terrestrial as they become older and heavier. Boas will strike when threatened, and will bite in defense. This bite can be painful, but is rarely dangerous.
- Length: 1 – 4m (3 – 13ft)
- Weight: 27 kg (60 pounds)
- Life span: 25+ years
- Diet: small rodents, birds, lizards
- No. offspring: 20 – 60 babies
- Gestation: 130 (+/- 10)