Taiwan least weasel Mustela formosana

What are mammals?

Mammals are the general terms for vertebrates of the Class Mammalia. Mammals can be very large, like the whales and dolphins in the ocean, and elephants on land, down through buffalo and domestic cattle, lions and tigers, dogs and cats, rats, mice and bats. Some mammals can be just a few centimeters in size. A common feature of mammals is hair. They are viviparous (except for the platypus and moles), the females have mammary glands and secret milk to nurse the young. Like the birds, the body temperature of mammals does not change with that of the environment as a general rule.