Learn what makes an animal a mammal , with examples of different orders and species. Find out how mammals evolved, their distinctive features, and some interesting facts. Most mammals , including the six most species-rich orders, belong to the placental group. The three largest orders in numbers of species are Rodentia: mice, rats, porcupines, beavers, capybaras, and other gnawing mammals ; Chiroptera: bats; and Eulipotyphla: shrews, moles, and solenodons. Mammal or class Mammalia is a group of most advanced animals concerning evolutionary aspects. Class mammals belong to the subphylum Vertebrata or Craniata. The notochord of vertebrates converted to a veritable column during the embryo stage. Among all vertebrates, mammals have the most advanced evolutionary features. Mammals' meaning suggests the presence of mammary glands in the female suckling the young ones. The number of species is around 5500. Mammals originated in the Triassic, about ... Mammals are one of the most diverse and fascinating groups of animals on Earth. From the tiny bumblebee bat to the gigantic blue whale, mammals have evolved to occupy nearly every ecosystem on the planet. They are warm-blooded vertebrates characterized by their ability to produce milk, grow hair or fur, and exhibit high levels of intelligence compared to other animal classes.
