What are the main orders of placental mammals? What are some representative species and distinguishing features of each of those orders?
The orders into which placental mammals are divided are the following: Artiodactyls, mammals with an even number of fingers in claws or paws like, e.g., cows, sheep, giraffes. Carnivorous, predators with canine teeth like dogs, lions, tigers. Cetaceans, aquatic animals without posterior limbs and similar to fishes, like whales and dolphins. Edentates, creatures with rare or absent teeth, like sloths, armadillos, anteaters. Lagomorphs, small-sized mammals having three pairs of continuously growing incisive teeth specialized in gnawing, like rabbits and hares. Perissodactyls, also known as ungulates (hooved), big-sized animals with an odd number of fingers in each paw, e.g., horses and rhinos. Primates, characterized by the big cranium and well-developed brain, like humans and apes. Proboscideans, big-sized animals whose nose and superior lip form the trunk (snout), e.g., elephants. Chiropterans, flying nocturnal mammals (bats). Rodents, animals with two pairs of continuously growing incisive teeth, e.g., mice, rats, castors, squirrels. Sirenians, aquatic mammals of freshwater, deprived of posterior limbs, like dugongs and manatees.
