Anatomy of Boa Constrictor

Boa constrictors are snakes known for their size and hunting methods. Boas don't use venom like other snakes, but instead wrap their thick bodies around their victims, stopping their hearts and then swallowing the victim whole. Boas rely on a unique physical anatomy to survive.

  1. Tongue and Jacobson's Organ

    • Two vital features of the boa's anatomy are its tongue and an organ on the roof of its mouth known as the Jacobson's organ. The forked tongue flicks the air very quickly and captures particles, then retracts into the mouth and deposits the particles onto the Jacobson's organ, which reads them. These two features are essential tools in the boa's arsenal, since the particles can tell it whether something is potentially food, danger or a mate.

    Teeth and Mouth

    • The teeth of a boa are typically very small, about the size of pins, with two rows lining the top of the mouth and a single row lining the bottom. They curve back slightly, however, to prevent whatever they grab from escaping. The lower jaw of the boa's mouth is not connected to the skull, meaning that it can be dislocated to allow the mouth to open abnormally wide. This lets the boa swallow prey that might otherwise be too large.

    Eyes and Ears

    • Boa constrictors have eyes with straight, vertical pupils that can take in a lot of light to help the animal hunt at night. They do not have eyelids, but instead rely on an ocular scale that covers the eye to protect it from dirt, dust and other debris. Like all snakes, boas do not have external ears, but use a weak set of internal ears to sense nearby vibrations.

    Windpipe

    • The boa has developed an adaptive windpipe with an opening near the front and bottom of its mouth, which allows the snake to breathe while it eats. Swallowing prey whole can be a long process, particularly if it's larger than the snake's head, so the windpipe prevents suffocation. Boas also use their windpipes to produce their famous hisses, which is accomplished by taking in air and powerfully expelling it via the windpipe.

    Body and Scales

    • Most boa constrictors have bodies that are long and very thick, since they build up fat reserves to compensate for long periods between meals. Their scales are really not scales at all, but a pattern of intricately folded skin. These folds allow the snake to tightly grip surfaces and aid in locomotion. They do, however, have a set of true scales on their bellies, known as ventral scales.

    Lungs and Ribs

    • Boa constrictors, like their python cousins, have a complete set of right and left lungs. This contrasts with many other snake species, which have retained only the right lung. The backbone of a boa is very flexible and contains hundreds of vertebrate, each of which controls a set of ribs. In turn, these ribs control the movement of the ventral scales on the belly, providing movement.

    Sex Organs

    • There are spurs on the bottom of a boa near the base of the tail. These limb-like appendages are actually the remnants of long-gone legs. The male has much bigger spurs than the female and uses them for stimulating and holding her during mating. The cloaca is also found on both males and females. It is a vent near the base of the tail that is used for urination, defecation, reproduction and to deliver live young.