According to my views and thoughts I really feel it’s fun to be mammals than reptiles or a fish amphibian or an insect. There are basically two cogent reasons to understand it and advantages of being a mammals. Mammals are vertebrates within the class Mammalia, a clade of endothermic amniotes distinguished from reptiles (including birds) by they possess a neocortex , hair, three middle ear bones and mammary glands. Females of all mammal species nurse their young with milk, secreted from the mammary glands (SIMPSON, 1937n.d.).