A constrictor is a type of snake that kills its prey by wrapping its powerful body around the animal and squeezing tighter and tighter until the prey cannot breathe. Boa constrictors and pythons are famous examples. These snakes don't have venom, so they rely on their muscular coils instead.

When a constrictor hunts, it strikes quickly and loops its body around its prey. Each time the trapped animal exhales, the snake tightens its grip a little more, preventing the next breath. Despite what you might see in movies, constrictors don't crush bones. They hold on until the animal dies from lack of air or blood flow.

You might hear constrictor used more broadly to describe anything that squeezes or tightens around something else. For instance, a tight collar might feel like a constrictor around your neck, or you could say that heavy traffic constricts the flow of cars on a highway. But when you hear “constrictor” without any other context, it almost always means one of those impressive snakes that hunt with the power of their muscular embrace.