Why do we have hairy arms?

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Hair is a normal and natural part of the human body. Many people have hair on their heads and it could be yellow (blonde), red/orange, brown, black or grey/white in colour. And you may choose to wear your head hair long or short or style it in different ways.

But have you thought about the hair on other parts of your body? Like your eyebrows or nose hairs or toe hairs? My friend’s daughter has and she wants to know why do people have hairy arms and why are grown-ups hairier than children? So let’s find out…

People (or human beings) belong to a group of animals that we call ‘mammals‘. And although there are many different types, shapes and sizes of animals in this group, there are some things that all mammals have in common:

  • Mammals have warm blood, which means that they can control their own body temperature
  • Mammals have backbones
  • Female (or girl) mammals give birth to live babies and feed them milk that they make with their bodies
  • And mammals have hair or fur on their bodies

So, humans have hairs on most of the outside parts of their bodies. Some of these hairs are short and soft – like the ones that are on your arms and legs. Some of these hairs are thick and dark – like the ones that grow in a man’s beard. And sometimes we let the ones that grow from the tops of our heads grow really long.

Hair is there to help keep our bodies warm by trapping air close to our skin. Hair also helps us to sense temperature changes and changes in our surroundings. And hairy bits like our eyebrows and nose hairs stop dirt and germs from getting into our bodies.

As we grow up from children into adults, our bodies become more hairy. And some of those hairs become darker and thicker and easier to see.

So, we have hair on our arms because we are mammals and the hair helps to keep our bodies warm and sense changes in the world around us. And grown-ups look hairier than children because some of their hairs have grown thicker and darker.

If you want to find out more about hair, check out this page of fun hair facts!

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