1. By Kelsey Hamilton

2.  Mammals are the only living organisms to have hair or fur. This helps to keep the mammal warm.  All mammals have four-chambered hearts.  Mammals are also endothermic which means that no matter what their surroundings are they can maintain there body temp.

3.  Mammals also have mammary glands which secrete milk. This aids in the way mammals nurse their young.  Mammals also have a sheet of muscle called the diaphragm. This allows the chest cavity to expand allowing the mammal to breathe.

4.  Mammals also give live birth.  They also have a very developed brain and nervous system which gives them the ability to learn.  Mammals also have modified limbs.  They have different types of teeth which are modified to the types of food they eat.