First, they care for their young, but there are a few other reptiles that do that too. Crocodilians also have a four chambered heart, while other reptiles have a three chambered heart. Four chambers are much more efficient, but they cause problems when the alligator needs to go dormant during cold weather. To solve that problem, they have a valve that allows the blood from the two chambers to mix, letting them lower their metabolism when they need to.