The Surprising Way Boa Constrictors Really Kill Their Prey

For decades, scientists thought that boa constrictors suffocated their victims to death by cutting off oxygen. Now, new research suggests that the snake species may actually kill their prey primarily by cutting off the flow of blood through the body’s circulatory system.

Researchers allowed boa constrictors to attack rats while measuring how the prey’s body responded, including taking blood pressure and heart rate measurements. The study, published in the Journal of Experimental Biology, suggests that the snake’s grip cuts off circulation almost immediately. The lack of blood flow causes organs like the liver, brain and heart to stop functioning, causing death.

These results don’t mean that prey doesn’t also suffocate, but the loss of blood flow throughout the body kills more quickly than the inability to breathe. “Rather than suffocation, circulatory arrest may be the most proximate cause of death during snake constriction,” the researchers wrote.

Researchers performed the experiment on 24 lab rats that were given anesthesia prior to the test to reduce suffering. Scientists told the BBC that the research could provide insight on how to treat human crush injuries.