What is a mammal?
Mammal traits:
1. Mother's Milk
- Almost all mammals give birth to live young. Female mammals are the only animals on earth that make milk for their young. The milk is rich in vitamins and nutrients needed for the young to grow up strong and healthy.
2. Warm Blooded
- Mammals are warm blooded; meaning that they can create their own body heat to stay at the body temperture they need to stay alive.
3. Bigger Brains 
- Mammals have larger, more developed brains than other animals. Most mammals are able to learn new things so that they can survive in new situations if they need to. They are able to adapt to their surroundings.
4. Hair
- Mammals are the only animals with hair, also known as fur. Their fur helps protect them from wind, rain, cold, sun, insects and other things.
Here are some websites to help you learn more interesting things about mammals:
http://animals.nationalgeographic.com/animals/mammals/
http://www.neok12.com/Mammals.htm
http://nationalzoo.si.edu/Animals/SmallMammals/ForKids/default.cfm