Myth Debunked: Boa Constrictors Don’t Suffocate Prey to Death. By Laura Geggel. livescience.com. July 22, 2015.Boa constrictors are notorious for their deadly grip, squeezing their next meal until it expires. But scientists have long wondered whether this fatal hug kills prey by suffocation or by obstructing blood flow in the snake’s victims. Now, a new study finds that rats attacked by boas don’t die from a lack of air. Instead, the boa’s tight coils block the rat’s blood flow, leading to circulatory arrest. That deadly grip helps to more quickly subdue rats and other prey that might be clawing back, allowing the snake to quickly end the struggle and preserve its energy, the researchers said.

"This is such an efficient behavior, and it allows us to realize that this behavior was really important in snake evolution," said lead researcher Scott Boback, an associate professor of biology at Dickinson College in Pennsylvania. "[Constriction] is extremely efficient at killing their prey and allowing them to be successful." [Watch a Boa Constrictor Subdue and Devour a Howler Monkey (Video)]Watch related video: 

How a boa constrictor squeezes its prey to death