There are more than 3,700 species of snakes ( Serpentes), and they're found in every continent except Antarctica, and across an array of habitats from rainforest to deserts. " could not evolve to the exaggerated levels we see today without the ability to breath during both the killing of prey with constriction, and the ingestion of large prey items." Snakes Use Their Rib Cage and Blood Pressure. "We think modular lung ventilation preceded or evolved in concert with constriction and large prey ingestion," Dr Capano said. A recovering boa constrictor feeds on a mouse at the Animal Hospital at the Niteroi Zoo, some 25 kms north of Rio de Janeiro, Brazil on August 5, 2009.
In some cases, this will encourage the snake to let go faster. The researchers think that the levator costa muscles are integral to snakes' ability to selectively engage ribs, and that this likely developed very early in snake evolution. If you have a spray bottle handy of vinegar and water, you may want to spray the boa constrictor face. "If you look at other animals, even us, we breathe with the whole rib cage." Loading "We didn't know until we checked," said Dr Palci, who wasn't involved with this study. Given that a snake's ribs run almost the entire length of the body, it makes sense they would conserve energy by not using all the ribs to inflate their lungs.Įven so, researchers couldn't assume that was the case, according to reptile evolutionary biologist Alessandro Palci from the University of Adelaide. What that means is that when their lungs are partially impeded by a meal, boa constrictors are able to use just a couple of ribs to compress their lungs.Īnd when their lungs are completely obstructed, they're able to engage the pump region of the lung to move air around. " could effectively turn off one set, and turn on another at will throughout the body." "We found that boa constrictors were able to activate very discrete sets of ribs," Dr Capano said. They then used a combination of X-ray, videography, and other scanning methods to study the rib movement of the snakes, and in particular where that rib movement was facilitating breathing. So scientists applied blood-pressure cuffs - the type of inflatable cuff that doctors use to take our blood pressure - to restrict movement along body sections of boa constrictors. The "pump" can also be used to help snakes hiss, but that's another story. In other words, the front part of the lungs behave like ours, where oxygen and other gases can enter and exit the bloodstream, while the rear of the lungs are more like a pump to get air moving around. "The back sections are avascular or 'saccular', much like a simple balloon, and are used primarily for ventilation and moving air." "These long lungs are also interesting in that only the front regions do gas exchange," Dr Capano said. In many snakes, the smaller left lung is basically vestigial - it's evolved to a point where it has little to no purpose, and all gas exchange happens with the longer lung.
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