Eventually, they developed adaptations that allowed them to become oceanic predators. Other features that are common among mammals are not necessarily exhibited by all mammals. Here is a list of other characteristics that are common among mammals. Remember to be a mammal you do not have to exhibit all of the characteristics below. The ability to maintain a constant body temperature.
Lower jaw is made of a single bone.
Have a four-chambered heart. They possess a secondary palette separating their eating from their breathing. A muscular diaphram is present. Highly developed brains. Fertilization is accomplished internally.