Boa Constrictor

Boa constrictor

A large, nonvenomous snake of Central and South America, also called the red-tailed boa, that squeezes its prey.

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About the Boa Constrictor

Boa constrictors live from northern Mexico to Argentina, in deserts, rainforests, savannas and farm fields. Newborns are about 20 inches long, and adults can reach 13 feet and over 100 pounds. Their tan, green, red or yellow bodies have patterns that help them hide. They eat lizards, birds, opossums, bats, rats and squirrels, and hunt mostly at night.^[1]

Quick facts

Scientific name: Boa constrictor^[1]
Size: About 20 inches at birth; up to 13 feet as adults.^[1]
Weight: Over 100 pounds when full grown.^[1]
Lifespan: 20 to 30 years in the wild.^[1]
Diet: Carnivore. Lizards, birds, opossums, bats, mongooses, rats and squirrels.^[1]
Habitat: Deserts, wet tropical forests, open savannas and farm fields.^[1]
Where it lives: Northern Mexico to Argentina.^[1]
Group life: Solitary. Hunts at night.^[1]
Babies: 10 to 64 live young, average 25.^[1]
Conservation status: Least Concern (IUCN Red List, assessed 2014).^[2]

Fun facts

Boas stop their prey's blood flow instead of crushing it.^[1]
Some families in South America keep boas at home to catch rats.^[1]
Boa constrictors can swim but prefer to stay on land.^[1]

Vocabulary

constrictor: A snake that kills prey by wrapping around it and squeezing.
nonvenomous: Not able to inject poison.
ambush predator: A hunter that hides and waits for prey to come close.
neonate: A newborn animal.
nocturnal: Active mainly at night.

See it in person

San Francisco Zoo & GardensSan Francisco, California · ReptilesSee this area on the zoo's website ↗
Oakland ZooOakland, California · Reptile and Amphibian Discovery RoomSee this animal on the zoo's website ↗

These zoos had this animal when we gathered our information, but animals sometimes move. Check the zoo's website or contact the zoo before you visit.

Sources

[1] Smithsonian's National Zoo & Conservation Biology Institute. “Boa constrictor.” https://nationalzoo.si.edu/animals/boa-constrictor (accessed 2026-10-02)
[2] IUCN Red List of Threatened Species. “Boa constrictor (Boa Constrictor).” https://www.iucnredlist.org/species/197462/2486405 (accessed 2026-10-02)