The boa constrictor’s choke maintain is an iconic animal assault. By coiling round its prey, a snake can squeeze the life out of a sufferer in mere minutes earlier than gulping it down entire (SN: 8/9/15). But it’s been unclear simply how Boa constrictor squeezes so arduous — or swallows one thing as huge as a monkey — with out suffocating itself.
Now, experiments present that when one a part of a boa constrictor’s rib cage is compressed — stopping the a part of its lungs enclosed there from drawing in air — the snake can transfer one other part of its rib cage to inflate its lungs there. Boas and different snakes in all probability couldn’t have began throttling and swallowing massive prey with out this means, researchers report March 24 within the Journal of Experimental Biology.
Biologist John Capano of Brown University in Providence, R.I., and colleagues implanted steel markers on the ribs of three boa constrictors, about one-third and midway down the animals’ our bodies. Tracking these markers in X-ray movies of the animals let the researchers map rib motions over completely different elements of the snakes’ lungs.
In these movies, the crew wrapped a blood strain cuff round completely different elements of the animals’ our bodies. Then, the scientists elevated the cuff’s strain till the rib cage couldn’t transfer in that space — mimicking the impact of a snake utilizing that a part of its physique to grip or gulp down prey.
When gripped by a cuff about one-third of the best way down their physique, snakes breathed by transferring some ribs nearer to their tails. When wrapped in a cuff about midway down their physique, snakes breathed by transferring some ribs nearer to their heads. “They can basically just breathe wherever they want,” Capano says. That makes him ponder whether snakes additionally alter their respiratory throughout different actions that compress their our bodies, akin to slithering.