Other common names
Red-tailed boa, Common boa
Most adult boa constrictors are about 10-16 feet (3-5 m) in total length. These are very large, stout-bodied snakes with dark brown hourglass-shaped saddles down the body that become reddish bands towards the tail. The background coloration is usually tan, light brown, grayish brown, or cream colored. The top of the head is tannish with a thin, dark stripe down the middle. There are dark, elongate markings behind the eyes that are often bordered by white below. Juvenile color pattern is similar to that of adults, except the coloration is more vivid.
Range in Florida
Boa constrictors are a non-native species from Latin America that have been established in Florida since perhaps the 1970s. Although they have been introduced to numerous areas in Florida, they are currently known to be established and breeding only in and around the Charles Deering Estate in Miami, Miami-Dade County.
Assessment of risk to people and pets
Non-venomous. Boa constrictors may bite to defend themselves. Small individuals are not generally dangerous to people or pets. However, larger boa constrictors have large, sharp teeth, and their bites can cause severe lacerations. Large animals are also fully capable of eating dogs and cats. Virtually all bites occur when the snakes are intentionally bothered.
Comparison with other species
Burmese python (Python bivittatus) Burmese pythons have bold, dark, dorsal blotches separated by thin light-colored bars. The belly is light colored in the center with small dark spots along the sides.
African rock python (Python sebae) African rock pythons have two mostly continuous and irregular dark blotches down the back that are bordered by black and white.
Most adult boa constrictors are 10-116 inches (25-295 cm) in total length. These are very large, stout-bodied snakes with dark brown hourglass-shaped saddles down the body that become reddish bands towards the tail. The background coloration is usually tan, light brown, grayish brown, or cream colored. The belly is light-colored and mottled with dark spots or smudges. The top of the head is tannish with a thin, dark stripe down the middle. There are dark, elongate markings behind the eyes that are often bordered by white below. The scales on the body are small and smooth. The pupil is vertically elliptical (cat-like). Juvenile color pattern is similar to that of adults, except the coloration is more vivid.
In Florida, boa constrictors have been found in diverse habitats including tropical hardwood hammocks, pine rocklands, mangrove swamps, landscaped areas, along canals and oolitic limestone walls, and occasionally in neighborhoods. The snakes may be found on the ground or in trees depending on the type of habitat and size of the snake (larger snakes are more often found on the ground).
Boa constrictors are nocturnal and typically remain well hidden in dense vegetation or burrows during the day to avoid detection. However, if they are cornered, both juveniles and adults may hiss loudly, gave their mouths open, and quickly strike at the attacker. If grabbed or pinned, they may bite the attacker and hold on while writhing, constricting, and releasing foul-smelling musk from a pair of glands in the base of the tail. Nonetheless, these snakes are not aggressive, and striking is only used in defense as a last resort.
Boa constrictors in Florida are known to feed on rodents (e.g., squirrels) and opossums. However, these powerful constrictors are presumably also eating other native mammals, birds, green iguanas, and feral cats.
In Florida, females give live birth to 24-47 young between May and August. However, boa constrictors are known to give birth to as many as 64 young in their native range. Newborns in Florida are 10-18 inches (25-45 cm) in total length.
Boa constrictor (Boa constrictor constrictor) The boa constrictor population established in Florida is thought to have originated from snakes imported from Colombia based on color pattern and historical data regarding the importation of these snakes.
At least 10 subspecies of boa constrictor have been recognized over time. Several studies have supported the elevation of many of these subspecies to full species status. However, these decisions are still not universally accepted, and analyses of additional data will likely result in additional changes to the taxonomy of these snakes.
County data coming soon.
If you have a new or interesting observation for this species, please email the herpetology staff at the Florida Museum.
Ernst, C.H. and E.M. Ernst. 2003. Snakes of the United States and Canada. Smithsonian Institution Press, Washington, DC. 668 pp.
Krysko, K.L., K.M. Enge, and P.E. Moler. 2019. Amphibians and Reptiles of Florida. University of Florida Press, Gainesville, Florida. 706 pp.
Powell, R., R. Conant, and J.T. Collins. 2016. Peterson Field Guide to Reptiles and Amphibians of Eastern and Central North America. Fourth edition. Houghton Mifflin Harcourt Publishing Company, Boston and New York. xiv + 494 pp.
Share your observations
You can help scientists better understand the biology and distribution of this species by sharing your observations. Send photos or videos of interesting observations, along with associated information, by emailing the herpetology staff at the Florida Museum for documentation in the Museum’s Herpetology Master Database. You can also post your observations on iNaturalist.
Additional helpful information
Do you have snakes around your house? Learn how to safely co-exist with snakes.
Still have questions about snakes or identifications? Feel free to email the herpetology staff at the Florida Museum with your questions or feedback on this profile.