What defines a mammal? http://www.dictionary.com/browse/mammal
1. They have mammary glands. Which means the mothers produce milk for their babies.
2. Mammals usually have hair on their bodies
3. Mammals have vertebrae
4. Mammals usually give live birth.
There is a wide range of mammals, there is around 5,000 species of mammals. http://www.factmonster.com/ipka/A0934288.html
Siberian Tiger http://www.naturephoto-cz.com/siberian-tiger-photo-18584.html
Killer whale http://www.naturephoto-cz.com/killer-whale-photo-14178.html