Diversity of Mammals 5th Grade
There are 3 main groups of mammals. These groups differ in how their young develop.
3 main groups of mammals: • 1) Monotremes • 2) Marsupials • 3) Placental Mammals
Monotremes are still considered mammals because they drink milk from their mother’s skin • An Anteater lay eggs directly into a pouch in the mother’s belly • A Duck-billed platypus lays her eggs in an underground nest
Monotremes • Egg-laying mammals • ONLY 3 SPECIES: -2 species of anteaters -Duck-billed platypus Why are these still considered mammals?
Marsupials • Mammals whose young are born at an early stage of development, and they usually continue to develop in a pouch on the mother’s body • short gestation period: the length of time between fertilization and birth
Examples of Marsupials • Kangaroos • Wallabies • Koalas • Wombats • Tasmanian Devils • Possums • Gliders
Placental Mammals • Develops inside its mother’s body until it can function independently • Name comes from placenta: an organ in pregnant female mammals that passes materials between the mother and the developing embryo • Food and oxygen pass from the mother to her young • An umbilical cord connects the young to the mother’s placenta.
Most mammals are placental mammals • The gestation period for animals usually depends on their size • Elephants have a 21 month gestation period • Mice have a 20 day gestation period
Placental Mammals – Carnivores: have large canine teeth and clawed toes to catch prey • River Otters • Dogs • Raccoons • Seals
Placental Mammals - Rabbits and Hares – Leaping mammals with long hind legs & long, curved incisors for gnawing
Placental Mammals -- Marine Mammals (marine = ocean) • Whales • Manatees • Dolphins
Placental Mammals –Rodents –are gnawing mammals such as mice rats, beavers, capybaras • Rats • Mice • Beavers • Capybaras Beaver Capybara
Placental Mammals – Trunk-nosed mammals • Elephants • Woolly Mammoth (extinct)
Placental Mammals – Flying Mammals • Bats –their wings are made of a thin skin that stretches from their wrists to the tips of their long finger bones Flying Fox Bat
Placental Mammals – Insectivores • Moles • Shrews
Placental Mammals - Primates • Have large brains and eyes that face forward • Include humans, monkeys, chimpanzees, orangutans, lemurs, etc.
Placental Mammals –Primates-Toothless Mammals • Have either very small or no teeth • Armadillos • Sloths
Placental Mammals –Primates - Hoofed Mammals • Cows • Deer • Pigs • Horses • Zebras
Caring for Young • Monotremes, Marsupials, and Placental Mammals all care for their young • Baby mammals are helpless for a long time after being born –many are born blind or withoutinsulating fur • Young mammals stay with their mothers or both parents for an extended period of time