Fur, milk and babies
What do a cat, a whale, a bat and you have in common? Find out what makes a mammal, and test how a furry coat keeps heat in.
Read
Mammals have hair or fur on their bodies.[3][2]
Mammal mothers feed their babies with milk from their own bodies.[3]
Mammals are warm-blooded: their bodies stay warm, even when it is cold outside.[2][7]
Most mammal babies are born alive. A few, like the platypus, hatch from eggs.[2][1]
You are a mammal too! Dolphins and whales are mammals that live in the sea and breathe air, and bats are the only mammals that can really fly.[1][4][5]
Try it: Furry coat test
You need
- Two identical jars or plastic bottles with lids
- Warm tap water (not hot)
- A woolly sock, a scarf or a piece of fake fur
- Elastic bands
- A thermometer (for the teacher)
Safety
Use warm tap water only, never hot water from a kettle. Wipe up spills straight away. Only the teacher uses a glass thermometer.
What to do
- Fill both jars with warm tap water and close the lids.
- Pull the woolly sock or fake fur over one jar. This jar has a 'fur coat'. Leave the other jar bare.
- Guess: which jar will stay warm longer?
- Wait 20 minutes. Do something else, then come back.
- Take the coat off. Touch both jars, or ask your teacher to measure the water. Which one is warmer?
What happens, and why?
The fur coat traps a layer of air close to the jar, and this keeps the heat in. A mammal's hair does the same job: it traps air close to the body and helps the animal stay warm.[1]
Play: Mammal or not?
Does it have hair and feed its babies milk? Tap the right group.
Your best score is kept only on this device. Nothing is sent anywhere.
Quiz
Other ages: Ages 10–11 · Ages 15–16