1. Placental Mammals
Classification

2. Order Rodentia: Gnawing Mammals
Largest mammalian order
1800 species
Mice, squirrels, porcupines, beavers…
Every continent except Antarctica
Large incisors in upper and lower jaw that grow throughout their life
Capybara

3. Order Rodentia Basically defenseless verse predators
Their reproduction habits allow them to survive
Reach sexual maturity quickly
Have short gestation period = give birth to altricial young
Produce large litters
Can reproduce frequently

4. Order Rodentia Field mice Weaned at three weeks
Independent at four weeks
Capable of bearing litters at six weeks
Capable of producing up to seventeen litters in a single year
A single individual could produce around 75 offspring in one year

5. Order Lagomorphs Rabbits, hares, pikas 80 species Herbivores
Fast moving
Reproductive habits similar to rodents
Also have a pair of always growing incisor teeth like rodents
Have an additional pair of chisel-shaped teeth outside the other pair

6. Order Carnivora: Meat-Eating Mammals
Most of the meat-eating mammals
Enlarged canine fangs and sharp molars for tearing flesh

7. Order Carnivora Family Felidae- cats, lions, tigers, cheetahs…
Family Ursidae- bears
Family Canidae- dogs, wolves, foxes, coyotes…
Three Pinniped Families- live in marine environments, spend most of their time in water, but come ashore to sleep, mate, and give birth, large bodies are not a problem in water, blubber keeps them warm in cold water, awkward movement on land
Phocidae- true seals, no visible ear flaps
Otariidae- eared seals including the sea lion
Odobenidae- walrus
Other families include mongooses, meerkats, hyenas, weasels, wolverines, skunks, raccoons…

8. Order Cetacea: Aquatic Mammals
Do not come ashore
Still must surface to breath
Whales, dolphins, porpoises
90 species

9. Order Cetacea
Whales are divided into two groups: toothed whales and baleen whales
Toothed whales and dolphins use echolocation
Baleen whales filter invertebrates from the water with a net of baleen in their mouth
Largest creature on Earth, the great blue whale, is a baleen whale

10. Order Cetacea Movement Pair of pectoral flippers supported by bones
Pair of boneless tail flukes
Flukes move up and down rather than side to side like the caudal fin in fish

11. Order Sirenia Manatees, dugongs, sea cows… 4 species
Herbivores feeding on underwater and floating foliage
Breathe through nostrils rather than blowholes like whales

12. Order Primates: Erect Mammals
Great apes, monkeys, lemurs…
Freely moving arms and legs with large hands and feet
Opposable thumbs for grasping items
Nails on most fingers and toes
Forward facing eyes, permitting binocular vision with depth perception
Poor sense of smell
Ability to walk erect when on land, though most of their time is spent in trees
A strong tendency to be social, often living in large groups
Less specialized teeth than those of most other mammals
A mostly vegetarian diet, possibly supplemented with eggs, insects, and occasionally other small animals

13. Order Primates
Chimpanzees are a type of ape, possibly the most intelligent animal
Some use tools and weapons
Some have been taught to communicate using sign language
Some show the ability to reason in order to solve problems

14. Order Artiodactyla: Even-Toed Ungulates
Pigs, hippos, camel, giraffes, cows, deer, sheep, goats…
Includes the ruminant suborder that chews the cud
Long legs with 2 or 4 functional hoofed toes
210 species

15. Order Perissodactyla: Odd-Toed Ungulates
Horse, donkey, zebra, rhinoceros
Herbivores
Rely on cecum rather than multichambered stomach to digest plant material = hindgut fermenters

16. Order Edentata: Toothless Mammals
Anteaters, armadillos, sloths
Anteaters are truly toothless
Others have peglike teeth, but lack enamel

17. Order Insectivora: Insect-Eating Mammals
Hedgehogs, moles, shrews…
400 species
One of the least studies orders of mammals
Sharp conical cusps
Pointy flexible noses are common
Acute sense of smell

18. Order Proboscidea: Trunked Mammals
Two species remain: the African and Asian elephant
Mammoths and mastodons are extinct
Flexible and useful trunk, essentially an elongation of the nose and upper lip
Ivory tusks are the two upper incisors that continually grow
Other teeth are 4 brick-sized molars
African elephant is the largest terrestrial (land) animal

19. Order Chiroptera: Flying Mammals
Only mammals capable of true flight
900 species of bats
Megachiropterans in tropics and subtropics of Africa, Asia, and Australia can grow up to 5.6 feet. They navigate by sight rather than sound and feed mainly on fruit and nectar
Microbats navigate using echolocation and feed on insects, fruit, nectar, sometimes fish and amphibians. The vampire bats in Central and South America do feed solely on blood