What makes an animal a mammal? Mammals are a particular class of animal. What makes an animal a mammal are several things. First, they must have glands that give milk. This is to feed their babies. Second, they are warm-blooded. Third, all mammals have fur or hair. Humans are mammals and so are dogs, whales, elephants, and horses. Most mammals have teeth with the exception of the ant eater which doesn’t have any teeth. Where do they live? Mammals live in all sorts of environments including the ocean, underground, and on land. Some mammals, bats for example, can even fly.
Three Types of Mammals Mammals are sometimes divided into three types based on how they give birth and take care of their young.
• Live young – Most mammals give birth to live young (instead of laying eggs like birds or reptiles). These mammals are called placental mammals.
• Marsupials – Marsupials are special types of mammals that carry their young in a pouch. Some marsupials include the kangaroo, the koala, and the opossum.
• Egg laying – A few mammals lay eggs, they are called monotremes. Monotremes include the platypus and the long-nosed spiny anteater.
Largest and Smallest Mammals The largest mammal is the Blue Whale which lives in the ocean and can grow to over 80 feet long. The largest land mammal is the elephant followed by the rhino and the hippo (which does spend a lot of time in the water). The smallest mammal is the Kitty’s hog-nosed bat. This bat is 1.2 inches long and weighs less than 1/2 a pound. It is also called the bumblebee bat.