Animals get around in many ways. They walk, run, hop, fly, swim, crawl and slither. Each body is shaped for the way it moves.
Key idea
Legs walk, run and hop. Wings fly. Fins and tails swim. A snake bends its whole body to slither.
Why it works
Strong back legs make a good hopper, like a rabbit or a frog. Light bones and wings make a good flyer. A smooth body with fins makes a good swimmer. No legs at all? A snake pushes its body against the ground.
Worked example: Let's think it through
A penguin has wings. Can it fly?
- A penguin's wings are stiff, flat flippers.
- They are too small to lift it into the air.
- Under water, it flaps them to zoom along.
Answer: No. A penguin uses its wings to swim.
Common mistake
Children often think anything with wings can fly, and every swimmer moves the same way. Penguins swim with their wings. A fish swishes its tail side to side, but a whale moves its tail up and down.
For the grown-up. Try the tail test at bath time or in a pool: wiggle your hand side to side like a fish tail, then up and down like a whale's. Whales and dolphins are mammals that breathe air, and their wide, flat tails beat up and down.