New Study: How Boa Constrictors Kill

For a long time, herpers have been irritably telling the uninitiated that constricting snakes don't kill by crushing their prey, but by suffocating it. The study described here shows that neither is exactly true. It's a matter of stopping the circulation, which allows much quicker kills than suffocation would. I don't think the article is quite right to call this heart attack, but the point is interesting nonetheless.

Jens Raschendorf/Creative Commons

Boa Constrictors Give Heart Attacks, They Don’t Suffocate: "Boa constrictors are widely believed to kill prey by cutting off the air flow and suffocating it. But a new study has revealed that this is a flawed line of thought. In reality, Boa constrictors kill prey by cutting off the blood flow and giving heart attacks."




3 comments:

  1. In the article we read:
    "Professor Boback explained that Dr. Hardy, an anesthesiologist and snake expert, focused on the speed of the kill when he wrote his study. Animals were simply dying too quickly for the cause of death to be suffocation. In his paper, the doctor stressed that suffocation can take several minutes to kill prey, whereas circulatory arrest will never take longer than 60 seconds.".
    I think, however, the speed of the kill depends on the size of the prey. For example, the circulatory arrest of big constrictor's preys - such as medium-sized caimans and crocodiles, deers, capybaras, monitor lizards, goats, wild pigs etc. - probably takes longer than 60 seconds.
    Do you agree, Gordon?

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    Replies
    1. I'm actually not sure. I know circulatory shock can happen to humans almost instantly in, for example, car wrecks. Among first-hand accounts of humans who have had close calls with big constrictors, I know of one large, athletic man who found himself fainting almost instantly when a pet python unexpectedly clamped down. He thinks he would have died if not for the intervention of another man. We know that a human can often survive four minutes without oxygen. Presumably, this man would have technically remained alive for a few minutes, but unconscious and helpless. For the snake's purposes, death doesn't matter; it only needs the prey to be helpless and not resume struggling. My guess is that a similar scenario applies to other large mammals, at least. A sudden plunge into unconsciousness would help explain why, for example, pigs fall prey to snakes. A pig of reasonable size would seem too formidable for a snake to take in a prolonged struggle, but not if it loses consciousness quickly.

      I'm not sure about reptiles, but my impression is that they are less hemodynamically resilient than mammals and perhaps more vulnerable to shock. This is why, for example, alligators lapse into unconsciousness when held on their backs.

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  2. Since Boa constrictor kills prey by circulatory arrest, it might be renamed "Boa vasoconstrictor"! :-)

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