An unexpected encounter with a large constrictor snake can trigger panic. Though the fear is understandable, attacks by a boa constrictor on an adult human are extremely rare. Boa constrictors are substantial, non-venomous snakes native to Central and South America and are also popular in the pet trade. Understanding the specific mechanics of a constrictor’s hold is the first step toward surviving such an encounter.
The Physiology of Constriction
The danger from a constrictor does not come from crushing bones, which is a common misconception. Instead, a boa constrictor subdues its prey by cutting off blood flow, leading to circulatory arrest faster than suffocation. The snake’s grip rapidly impedes the flow of blood, causing a drop in arterial pressure and a rise in venous pressure in the victim.
This mechanism starves the heart and brain of oxygen, leading to unconsciousness within seconds and cardiac arrest shortly thereafter. The snake does not tighten simply because the victim struggles. Rather, it monitors the victim’s heart rate and applies pressure incrementally, tightening its coils each time the prey exhales or its heart weakens. This is an energy-efficient hunting strategy targeting the vascular system.
Protecting Your Airway and Locating the Head
The strategic response must focus on creating and maintaining space around your chest and neck. Remaining calm is important, as struggling can encourage the snake to tighten its hold. The goal is to prevent the constrictor from fully compressing the rib cage, which restricts the diaphragm’s ability to move and limits the space for blood vessels to function.
Use your hands or elbows to wedge against the snake’s coils, forming a rigid “splint” around your torso. This creates a pocket of space, allowing your chest cavity to expand enough for a full breath even when compressed. While protecting your breathing, locate the snake’s head. Controlling the head is important because it is the point of mechanical control the snake uses to initiate and adjust the constriction.
The Unwinding Technique and Safe Release
Once you have established breathing space and located the snake’s head, you can begin the physical maneuver for escape. The most effective method is the “unzipping” technique, which involves unwrapping the snake’s coils starting from the tail end. The tail is the last part of the snake to wrap around its prey, and it represents the weakest point of the constriction.
By peeling the coil off like a sticker, you leverage the snake’s muscular strength distribution, making the tail section easier to overpower. Focus on loosening the outermost coil first, moving from the tail toward the head. Trying to unwind the coils from the head end is often futile and wastes time, as the snake will instinctively tighten the grip closer to its head.
Once the snake is fully unwrapped, move away quickly to prevent a second strike or constriction attempt. After the encounter, check for any puncture wounds from the snake’s teeth, which are angled backward and can cause deep tears. If you sustained pressure for any significant time, seeking medical attention is important to check for internal injuries or circulatory issues that may have resulted from the sustained compression.