Their active metabolism is supported by an efficient respiratory system that uses a sheet of muscle called the diaphragm to help ventilate the lungs. Mammals as Learners Mammals have larger brains than other vertebrates of equivalent size, and seem to be the most capable learners. The relatively long duration of parental care extends the time for parents to teach important skills to their young. Reproduction Mammary glands that produce milk are as distinctively mammalian as hair. All mammalian mothers nourish their babies with milk, a balanced diet rich in fats, sugars, proteins, minerals, and vitamins.
Most mammals bear their young live.
Fertilization is internal, and the egg develops into an embryo within the uterus of the female reproductive tract. In placental mammals, the lining of the mother's uterus and membranes arising from the embryo collectively form a placenta, where nutrients diffuse into the embryo's blood. Teeth Differentiation of teeth is another important mammalian trait. Whereas the teeth of reptiles are generally conical and uniform is size, the teeth of most mammal species come in a variety of sizes and shapes adapted for chewing many kinds of foods. One of these species is a member of the Rodentia Order.