Placental Mammals Classification

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

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

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

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

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

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…

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

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

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

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

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

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

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

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

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

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

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

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