Spitting Cobra Secrets

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Scientists learn secrets of spitting cobras
Process is like a baseball pitcher psyching out batters before a throw


A spitting cobra in action. Scientists have explained the precise aim of a venom-spitting cobra as a two-part process: the muscular wind-up and the psychological psych-out of the victim.

By Jennifer Viegas
updated 1/21/2009 1:22:15 PM ET

Spitting cobras spew blinding venom toward the eyes and face of victims with surprising accuracy, and now researchers know how they do it.

Venom spitting — a defense mechanism only — is a two-part process that's part muscle and part like a baseball pitcher psyching out batters before winding up before a throw, indicates a new study published in the latest issue of Physiological and Biochemical Zoology.

"Since the venom can cover a distance of over 6.5 feet, and the snakes appear to be very accurate, it is presumed to be a good deterrent," said Bruce Young, an associate professor of biology at Washburn University and lead author of the study.

For the study, Young and colleagues Melissa Boetig and Guido Westhoff analyzed adult, captive specimens of the red spitting cobra, the black-neck spitting cobra and the black-and-white spitting cobra.

Equipped with a special visor to protect his eyes, Young had the indelicate task of taunting the snakes by moving his head in front of them. The visor was outfitted with a custom-made accelerometer system allowing a computer to track the movements of Young's head in three dimensions.

During one experiment, the researchers also anesthetized some of the snakes and implanted electromagnetic leads to monitor a muscle that controls the venom gland, as well as the movements of the snake's head and neck.

The scientists found that before a spitting cobra releases its venom, a muscle contracts, displacing tissue barriers in the snake's fangs that normally prevent the flow of venom. More muscle contractions increase pressure within the venom gland, propelling a stream of venom out the fangs.