noun, plural: mammals
Any of the endothermic vertebrates belonging to class Mammalia, which are identifiable by the following characteristics: a neocortex, three middle ear bones, a lower jaw made of a single bone, a hairy body covering, a thoracic diaphragm, a four-chambered heart, and females that are mostly viviparous
Monotremes, marsupials (e.g. kangaroos) and placentals (e.g. primates, elephants, dolphins, cattle, etc.) are examples of mammals. With the exception of the monotremes (which are oviparous), most female mammals are viviparous. Viviparous mammals give birth to live young and nourish their newborn with milk produced from their mammary glands. Mother monotremes do not have nipples; thus, they feed their young with milk through specialized ducts at their abdomen. In dayak fruit bats, males are the ones producing milk to nourish the young.
Word origin: Latin mamma ( breast)