Answer: a warm-blooded vertebrate animal of a class that is distinguished by the possession of hair or fur, the secretion of milk by females for the nourishment of the young, and (typically) the birth of live young. ( A animal with hair)
examples: dog, cat, platypus, wombat, kangaroo, tiger, lion, koala, squirrel, horse, giraffe, deer, etc...
Explanation: if the animal has fur/hair its a mammal