When it takes a long time to swallow a big bite, you have to figure out a way to breathe at the same time. So, just how does a boa constrictor stay alive while dispatching and eating its prey?
When a constrictor starts ingesting a relatively large animal, the rib cage at the front of its body has to open to maximum capacity. That doesn’t leave much room for lung expansion in the same place. So, snakes developed a way to selectively use the ribs and muscles farther down their bodies for breathing.
The ribs serve as bellows for snakes to draw air into their lungs, which extend along much of their body. Depending on what they’re doing, snakes are able to shift that function among some 200 pairs of ribs.
It’s just another example of how evolution has figured out a way for animals to get the job done.