Here's why:
* Mammals are warm-blooded animals that have fur or hair, give birth to live young, and nurse their offspring with milk.
* Reptiles are cold-blooded animals that have scales, lay eggs, and breathe air with lungs.
* Amphibians are cold-blooded animals that live both on land and in water. They have smooth, moist skin and lay eggs.
Arabian horses clearly fit the description of mammals!