Can Boa Constrictors Breathe While They Constrict?

A new study reveals how boa constrictors avoid suffocating themselves while constricting their prey.

Transcript

00:00When boa constrictors squeeze the life out of their prey, how do they avoid suffocating themselves in the process?

00:06A new study published in the Journal of Experimental Biology solves this mystery.

00:15It turns out that boa constrictors can rapidly adjust which section of their ribcage they use to breathe.

00:21So if one portion of the snake is, say, busy constricting a squirrel,

00:24a different portion can take over and allow air to continue moving in and out of their lungs.

00:29Researchers figured this out by placing blood pressure cuffs on boa constrictors to restrict the movement of their ribs.

00:35They then used a special technique called XROM to track how the snake's ribs were moving in real time.

00:41The team also used various techniques to measure air flow in and out of the snake's lungs and the electrical activity of different muscles.

00:48Unlike humans, snakes don't have a diaphragm to help pull air into their lungs and then push it back out.

00:54Instead, the animals completely rely on muscles attached to their ribs to alter the volume of their ribcage

00:59and thus allow their lungs to expand and compress.

01:02In these video clips, you can see how when one section of the ribcage is constricted by the blood pressure cuff,

01:07another section takes over to ventilate the lungs.

01:10Even when only the back of the lung, towards the snake's tail, can inflate, air still travels through the rest of the lung,

01:16allowing oxygen to pass into the bloodstream and waste products to pass back out.

01:20Study author John Capano told me that the development of this form of lung ventilation

01:24was likely a key step in the evolution of snakes as we know them today.

01:28He said,

01:29What we postulate in this paper is that this sort of modular lung ventilation mechanism

01:34is a big part of how snakes evolved to be what they are today.

01:37It doesn't seem like you could evolve constriction to kill really big things if you're compromising lung ventilation.

01:44So if you ever see a boa constricting a cute, fuzzy animal, don't worry.

01:48The boa can breathe just fine.