Diversity of Mammals 5 th Grade
Dec 28, 2015
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
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 –Rodents –are gnawing mammals such as mice rats, beavers, capybaras
• Rats
• Mice
• Beavers
• Capybaras
Beaver
Capybara
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 - 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
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 without insulating fur
• Young mammals stay with their mothers or both parents for an extended period of time