Chapter 43 Mammals Section 3 Diversity of Mammals
Dec 30, 2015
Mammalian Orders• Mammals are classified into a
single order of monotremes, 7 orders of marsupials, & about 18 orders of placental mammals
Monotremes• Order Monotremata
• Egg-laying mammals
• Duckbill platypus- Australia- water resistent fur, webbed feet & flattened tail
• Spiny anteater- Australia- feed on ants & insects- sticky tongue
Marsupials• Order Marsupialia
• Majority live in Australia, and some live in New Guinea
• Virginia opossum- only marsupial in USA
• Have pouch to raise young in
Order Xenarthra• Anteaters, armadillos, & sloths
• Location: N. America, C. America, & S. America
• Xenarthra- “strange joints”
• Feed on insects or plants
Order Lagomorpha• Rabbits, hares, & pikas
• Double row of upper incisors, with two large front teeth backed by two smaller ones
• Teeth grow throughout lifetime & adapted to herbivorous diet
Order Rodentia• Rodents: squirrels, marmots,
chipmunks, gophers, muskrats, porcupines, mice, & rats
• Rodent’s teeth consist of a few molars or premolars and two pairs of incisors that grow all of the rodent’s life
Order Primates• Lemurs, tarsiers, monkeys,
gibbons, apes, & humans
• Omnivores; large brains
• Forward-facing eyes for depth perception
• Grasping hands, feet, and tails
Order Chiroptera• Mammals that truly fly- bats• Wing- modified front limb with a
membrane of skin that stretches between digits
• Use thumbs for walking, climbing, & grasping
• Small eyes & large ears for echolocation- active at night
Order Insectivora• Shrews, hedgehogs, & moles• N. America, Africa, & Europe• Most have long, pointed noses that
help them probe the soil for insects• Have sharp teeth to grasp & pierce
prey
Order Carnivora• Animals that eat meat- carnivores• Dogs, cats, raccoons, bears,
hyenas, otters, seals, & sea lions• Strong sense of smell and sight• Strong jaws, large teeth, clawed toes• Aquatic carnivores- pinnipeds- sea
lions, seals, walruses
Order Artiodactyla• Hoofed animals- ungulates
• Ungulates with even number of toes- artiodactyls- deer, cattle, giraffes, pigs, and camels
• Herbivores- most have rumen
• Molars are flat and large for grinding plants
Order Perissodactyla• Ungulates with an odd number of
toes- perissodactyls
• Horses, zebras, rhinoceros, & tapirs
• Location: Africa & Asia
• Have a cecum
Order Cetacea• Whales, dolphins, porpoises• Lack hind-limbs, have tails• Totally aquatic, but evolved from land • Breathe through modified nostrils-
blowhole• Use echolocation to locate prey,
navigate, & communicate• Toothed whales- dolphins, orcas,
sperm whale
Order Sirenia• Manatees and dugongs
• Herbivores
• Location: tropical seas, estuaries, and rivers
• Closely related to elephants- evolutionary speaking
Order Proboscidea• Asian and African Elephant• Largest living land mammal• African elephant- 13,200 lbs• Feed on plants for 18 hours each
day• Nose is modified into trunk for
grasping “proboscis”
Other Orders• The 12 orders just described
include most of the familiar placental mammals.
• The 6 remaining orders contain just 1% of the mammalian species.