Around 6,640 extant species of mammals have been described and divided into 27 orders. [2] The study of mammals is called mammalogy. The largest orders of mammals, by number of species, are the rodents, bats, and eulipotyphlans (including hedgehogs, moles and shrews).
Types of animals that are mammals include warm-blooded vertebrates that have hair or fur and whose babies drink milk. Unlike other animal types like birds and insects, all mammal babies drink milk that comes from their mother’s bodies.
Every major habitat has been exploited by mammals that swim, fly, run, burrow, glide, or climb. There are more than 6,800 species of living mammals, arranged in about 125 families and as many as 27–29 orders (familial and ordinal groupings sometimes vary among authorities).
Mammals include humans and all other animals that are warm-blooded vertebrates (vertebrates have backbones) with hair. They feed their young with milk and have a more well-developed brain than...