mammal

The term mammal refers to a class of warm-blooded vertebrate animals with several shared features. Most have hair or fur, and females produce milk to feed their young. That milk-feeding trait is the clearest sign of the group and is the reason for the name, which comes from the Latin word mamma, meaning "breast."

Mammals live in almost every part of the world. They can be as small as a shrew or as large as a blue whale. Some fly, like bats. Some swim, like whales and dolphins. Some dig underground, like moles, while others live in trees, like many monkeys. This wide range shows how varied this group is.

Many mammals give birth to live young, though a few, such as the platypus and echidna, lay eggs. They also have backbones, breathe air, and usually have different kinds of teeth for different kinds of food. Humans, dogs, cats, horses, bears, and whales are all examples.

When you use the word mammal, you are talking about one of the major groups of animals on Earth. It is a useful word for describing animals that are warm-blooded, have hair or fur at some stage of life, and feed their babies with milk.