1. ORDERS OF MAMMALS
Classified by: Structure of teeth, number and kinds of bones in the head, and method of reproduction.
M0NOTREMES:
Egg laying mammals: duckbill platypus & spiny anteater (echidna)
MARSUPIALS:
Pouched mammals: kangaroos, koalas, opossums
PLACENTALS:
Contained in 16 orders, w/higher metabolic rates
Order Insectivora: Insect eaters; tree shrews, hedgehogs, shrews and moles. High metabolic rate keep them always eating
Order Chiroptera: Different species of bats (eating habits)

2. ORDERS OF MAMMALS
Order Edentata: Animals w/o teeth, sloths, armadillos, anteaters
Order Rodentia: Rodents w/two long sharp front teeth. Mice, rats, squirrels, beavers, porcupines, & gophers.
Order Lagomorpha: Rabbits and hares; Similar to rodents
Order Carnivora: Meat eaters, wolves, cats dogs, bears, seals, most are terrestrial some aquatic
Order Cetacea: Truly aquatic mammals: whales, dolphins, & porpoises. Have lungs and circulatory system to permit deep dives, they have a thick subcutaneous fat, called blubber.
Order Sirenia: Aquatic, slow-moving herbivores, manatees
Order Artiodactyla: Large grazing mammals; cattle, sheep goats, hippos, giraffes, and pigs; Two toed, hoofed (ungulate)

6. ORDERS OF MAMMALS
Order Perissodactyla: Horses, zebras, tapirs, & rhinos; These are odd toed ungulates, w/ hooves forming from the center of the toe on each foot.
Order Proboscidea: Mammals w/trunks; Indian and African elephants, used to include the mastodons and mammoths
Order Primates: Have the most highly developed cerebrum and the most complicated behaviors. Monkey, apes, lemurs, humans. Some have a prehensile tail for grasping and climbing. Includes both new and old world monkeys.
HOW DO MAMMALS FIT INTO THIS WORLD?????
Food chains for each other, inhabiting all areas of the earth
Domesticated for pets, food, clothing
Negative impacts: carnivores, mice/rats, carry diseases, effect on the environment, grazing, dams, human stupidity