Mammals that give birth to very underdeveloped young that continue to grow outside the uterus; typically in a pouch

Mammals that give birth to young that are nourished by a placenta before birth; young are more developed compared to other mammals

Vascular structure that nourishes young while they are in the uterus; composed of tissues from both the mother and baby

Order of mammals that give birth to very underdeveloped young that continue to grow outside the uterus; typically in a pouch; includes kangaroo, wombat, Tasmanian devil, opossum

Order of mammals that are oviparous; they do not have nipples or teats, milk is secreted into indentations in the female's belly; includes duck-billed platypus and echidna

Order of mammals that are primarily insectivorous; they are typically small in size; includes hedgehogs, shrews, moles

Order of mammals that are the only mammals that have wings and can truly fly; many use echolocation to navigate; bats

Order of mammals that are considering gnawing mammals; they have two pairs of incisors that constantly grow; most eat seeds or plants; includes rats, mice, capybara, guinea pigs

Order of mammals that have very highly developed brains; most live in the tropics and subtropics; most have complex social systems; their front limbs are prehensile (grasp); includes monkeys, apes, humans, lemurs

Order of mammals that are considered to be the flesh eaters; their teeth are designed for tearing flesh; includes weasels, dogs, cats, raccoons, sea lions

Several mammalian orders in which the vast majority have hooves

Mammalian order that includes dugongs and manatees

Order of mammals that are considered to be the flesh eaters; their teeth are designed for tearing flesh; includes weasels, dogs, cats, raccoons, sea lions

Order of mammals that are rodent-like, but have a second pair of incisors growing behind the first pair; almost completely herbivorous; terrestrial; includes rabbits, hares, pikas

Mammalian order that are odd-toed hoofed mammals; includes zebras, donkeys, horses, rhinoceroses

Mammalian order that are even-toed hoofed mammals, most have 2 toes, some have 4 toes; includes cattle, deer, swine, hippo, sheep

Mammalian order that are completely aquatic, most are marine; anterior limbs form flippers, no posterior limbs; breathe through a blow hole; includes whales, dolphins, porpoises

Whales and porpoises that are primarily meat-eaters; have teeth and 1 blow hole; fluid-filled melon for echolocation

Whales that have plates in their mouths for filtering krill and other tiny food items from the water; have 2 blow holes