Boas kill by cutting off blood flow, not airflow


The rainbow boa Epicrates cenchria (shown) probably kills its prey by cutting off its captive's blood flow, not by suffocating it, as scientists had suspected.

karoH/Wikimedia Commons (CC BY-SA 3.0)

Suffocation seems to be too slow for boa constrictors. Instead, the snakes kill by cutting off their captive’s blood flow. 

An experiment on living, anaesthetized rats showed that the rodents’ blood flow slowed in a matter of seconds after the animal started to get squeezed by a boa. Loss of blood flow to the brain would make the animal pass out before losing the ability to breathe. That suggests that boa constrictors kill by cutting of blood flow, not airflow, researchers report July 22 in the Journal of Experimental Biology.

photo of Ashley Yeager

Ashley Yeager is the associate news editor at Science News. She has worked at The Scientist, the Simons Foundation, Duke University and the W.M. Keck Observatory, and was the web producer for Science News from 2013 to 2015. She has a bachelor’s degree in journalism from the University of Tennessee, Knoxville, and a master’s degree in science writing from MIT.

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