20.3 Classification of Mammals

Lesson Objectives

Learn about traditional classification of mammals.

Vocabulary

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Classification of Placental Mammals

Traditional classifications of mammals are based on similarities in structure and function. Increasingly, mammals are being classified on the basis of molecular similarities.

Traditional Classification

The most widely accepted traditional classification of mammals divides living placental mammals into 17 orders. These orders are shown in Table below. This classification of mammals was widely accepted for more than 50 years. Placental mammals are still commonly placed in these orders.

Remember, animals are classified like you would classify different types of Legos or other items. It’s just an easier way to keep similar things grouped together.

Order	Example	Sample Trait
Insectivora	mole	small sharp teeth
Edentata	anteater	few or no teeth
Pholidota	pangolin	large plate-like scales
Chiroptera	bat	digits support membranous wings
Carnivora	coyote	long pointed canine teeth
Rodentia	mouse	incisor teeth grow continuously
Lagomorpha	rabbit	chisel-like incisor teeth
Perissodactyla	horse	odd-toed hooves
Artiodactyla	deer	even-toed hooves
Cetacea	whale	paddle-like forelimbs
Primates	monkey	five digits on hands and feet
Proboscidea	elephant	tusks
Hyracoidea	hyrax	rubbery pads on feet
Dermoptera	colugo	membrane of skin between legs for gliding
Pinnipedia	seal	feet with fins
Sirenia	manatee	paddle-like tail
Tubulidentata	aardvark	teeth without enamel