what is a major difference between a squid heart and a human heart?
In humans, the four-chambered heart keeps oxygenated blood and deoxygenated blood in separate chambers. But in frogs, grooves called trabeculae keep the oxygenated blood separate from the deoxygenated blood in its one ventricle. Frogs can get oxygen not only from their lungs, but also from their skin, Mulcahy said.