![]() ![]() That would be a tall order for most animals, but not so for snakes: A boa’s lung, for instance, runs about 30 percent of its total body length, creating lots of space for air to be drawn in and expelled back out. Over the years, several biologists had come to suspect that boas and their kin might sidestep suffocation by moving their breath all around. The idea of localized breathing isn’t totally new. Read: How to kill a snake when you’re a snake But the boa constrictor-and its breath-finds a way through. Those acts are normally “at odds with each other,” says Jennifer Rieser, who uses biophysics to study snake movements at Emory University. ![]() Such maneuvering allows the boas to divert the business of breathing away from the parts of the body that are constricting or digesting prey, and toward the unencumbered bits that are free to expand, making it possible for the rib cage to simultaneously squash dinner down and balloon the lung out. And they can “choose any couple of ribs,” Capano told me, “and just use those.” The fingerlike bones flare out in isolated clusters, compelling only the bits of lung directly beneath to inflate-in effect adjusting which sections of the organ the snake uses to inhale. Boas are basically accordions of bone: They have hundreds of pairs of ribs, running nearly the entire length of their body. The key, he and his colleagues have found, is precise control. Capano has a particular way of describing this curious phenomenon, which has mystified snake aficionados for years: “How does one rib cage kill another rib cage without hurting itself?” But boas somehow manage the feat, then go on to swallow their prey whole, smooshing their chests from the outside, then the inside, breathing easy all the while. Constricting other animals to death is like trying to win a wrestling match while laced into a corset-a recipe, it would seem, for autoasphyxiation. “The entire front third of the body gets involved,” which is no fun at all for the organs inside, says John Capano, who studies the reptiles at Brown University. It also compresses the predator, putting an epic squeeze on the parts of the body that harbor the snake’s heart and the upper portions of its lungs and gut, sometimes for up to 45 minutes at a time. The curly-fry crush of a boa-which can exert pressures of up to 25 pounds per square inch-doesn’t just squish the life out of its prey. When a boa constrictor coils its midriff around a wriggling rat, it’s easy to feel sorry for the soon-to-be-lifeless rodent, its blood supply so blocked that its heart stops pumping.īut consider, too, the plight of the snake. ![]()
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