For most creatures, sitting down to digest a good meal isn't a time of pulse-racing physical exertion. But for pythons, digestion sends their pulse rate soaring as the reptile's three-chambered heart rises to the metabolic challenge. All reptile hearts have a single ventricle where oxygenated and deoxygenated bloods mix, reducing the amount of oxygen that can circulate around the reptile's body and limiting the creature's maximum metabolic rate. A muscular ridge partially divides all reptiles' ventricles, but never to the extent of developing two independent ventricle chambers. But Tobias Wang,Jordi Altimiras and Michael Axelsson knew that the muscular ridge in a python's heart is much larger than in many less active species. They wondered whether the size of the ventricle's ridge was in any way correlated with a reptile's metabolic demands. Working in Sweden, they tested how blood flows through a beating python heart, and were amazed when they found...

You do not currently have access to this content.