Boa constrictor

Boas eat animals.

They catch rats, birds, lizards and other small animals. They swallow their food whole.

Boa constrictors eat rats, squirrels, opossums, bats, birds, large lizards and even other snakes. Most of the time a boa is an ambush hunter: it waits quietly until an animal comes close. When food is hard to find, it moves around more to search.

The boa grabs its prey with small hooked teeth, wraps its body around it and squeezes, then swallows it whole. In some parts of South America, people even let boas into their homes to catch rats.

The diet includes mammals, birds, snakes and lizards (IUCN); the Smithsonian lists large lizards, small to medium birds, opossums, bats, mongooses, rats and squirrels. Boas are mostly ambush predators but forage more actively when prey is scarce.

Small, hooked teeth secure the prey while coils wrap around it. It was long believed that constrictors crush bones or stop breathing, but research described by the Smithsonian shows the squeeze causes circulatory arrest: pressure stops the heart from moving blood. Because they eat rodents, boas are valued as pest controllers in many parts of tropical America.

Boas like to be alone.

They are often busy at night. They wait very still for food to come close.

Boa constrictors usually live alone, except in the breeding season. They are often active at night, but they can be out and about in the daytime too.

A boa spends a lot of time waiting quietly in one spot, perfectly still and hidden by its pattern. Young boas climb a lot, while big adults are usually found on the ground. If you ever meet a big snake, stay back, leave it alone and tell a grown-up.

Boas are largely solitary outside the breeding season (Smithsonian). Activity has been recorded both by day and by night (IUCN), although the Smithsonian describes them as nocturnal hunters.

They are semiarboreal, with a shift from trees as juveniles to the ground as adults, and they adjust their foraging to prey density, from sit-and-wait ambush to active searching. Their adaptability is one reason released pets can survive where the climate is warm enough, as in southern Florida.

There are still many boa constrictors.

But people catch some for their skins and as pets. Pets should never be let go outside.

Boa constrictors are listed as least concern, because they live across a huge area. But their numbers are slowly falling in some places, where forests are cleared for farms, mines and oil, and where boas are caught for their skins, their meat and the pet trade.

Boas are among the most common snakes kept as pets. Some owners do not realize how big they grow, and a few release them. That is harmful: released boas can survive and cause problems for wild animals. Never let a pet go outside.

The IUCN lists Boa constrictor as Least Concern (assessed 2014, published 2021, flagged as needing an update) because of its very wide range and presumed large population, while noting a likely gradual decline. Threats are harvest for skins and meat, in places illegal, collection for the pet trade (CITES records more than 97,000 live boas traded in 2010 to 2018) and habitat loss to oil, mining and farming in Ecuador, Brazil, Peru and Argentina. The restricted-range subspecies B. c. ortoni of southern Ecuador and northern Peru is affected by habitat loss and persecution.

The Smithsonian notes that released pet boas have established breeding populations in southern Florida, and the IUCN lists an introduction to Puerto Rico.