lesson
Updated 6 days ago
Have you ever wondered why baby birds hatch out of brittle eggshells, but baby puppies and kittens arrive directly from their mother's body ready to wriggle and cuddle?
Most warm-blooded, furry animals belong to a group called placental mammals, which protect and nourish their babies inside the mother before birth.
How does a tiny unborn baby get all the food and air it needs to grow inside its mother?
Growing Inside: Embryo and Gestation
A new mammal begins as an embryo, which is a tiny ball of cells that starts dividing and forming organs after a mother's egg is fertilized.
Inside the mother's womb, the baby connects to a special sponge-like organ called the placenta, which delivers nutrients and oxygen directly from the mother's bloodstream.
The entire time a baby spends growing safely inside its mother is called gestation.
📊Interactive diagram
What happens once the baby mammal is fully developed and ready to meet the world?
Live Birth
Unlike frogs or robins that lay eggs outside the body, placental mammals give live birth, meaning the newborn emerges directly into the world.
Newborn mammals can breathe air with their lungs immediately, but they are fragile and completely dependent on their parents for warmth and safety.
Since newborn mammals do not have teeth for chewing solid food, how do they get their meals?