Animals Classification
Primary 4 · Science and Elementary Technology
Animals Classification
Lesson 5 of 5
15 min
Let's begin
Mutesi's hen has been sitting on her eggs for three weeks. One morning, tiny yellow chicks peep out of the cracked shells. That same week, the family goat gives birth to a little kid that stands up and drinks its mother's milk.
Both animals had babies, but in two different ways.
To reproduce means to make young of your own kind. Hens make chicks, goats make kids, and people make babies. Animals reproduce in two main ways.
These animals lay eggs, and the baby grows inside the egg, feeding on the food stored there (the yolk). When it is ready, it hatches. Scientists call egg-laying animals oviparous.
In these animals the baby grows inside the mother's body, in a part called the womb, until it is ready to be born alive. Scientists call them viviparous.
Almost all mammals do this: cow (calf), goat (kid), rabbit (kits), dog (puppies), bat, and people. After birth, mammal mothers feed their babies milk.
Fun fact: a few mammals in Australia, like the platypus, lay eggs, and a few snakes and fish give birth to live young. That is why we say "most".
A hen keeps her chicks warm under her wings, and a cow feeds her calf milk. But most fish and frogs leave their eggs. Many eggs and babies are eaten, so frogs and fish lay hundreds or thousands of eggs, and a few of them survive.
A calf looks like a small cow. But a frog changes shape as it grows: egg → tadpole → froglet (a tadpole with legs) → adult frog. A butterfly changes too: egg → caterpillar → pupa → butterfly.
Tip
Feathers? Then eggs. Fur and milk? Then live babies
Try each one first, then tap Show answer to check.
Does a duck lay eggs or give birth to live young?
Answer: It lays eggs. All birds lay eggs.
Does a bat lay eggs or give birth to live young? Why?
Answer: It gives birth to live young, because it is a mammal.
Why do frogs lay so many eggs?
Answer: Most of their eggs and tadpoles are eaten or die, so laying many means a few will grow up.
Put these in order: tadpole, adult frog, egg, froglet.
Answer: Egg → tadpole → froglet → adult frog.
What you learned today
Sources and credits
The exercises (Try it yourself and the practice questions) are written by Ganzaa.
This lesson adapts CC BY-SA material and is shared under CC BY-SA 4.0.
Quick check
Which animal gives birth to live young?
