Question: how does it react inside our bodies when we have goosebumps?

Claire El Mouden answered on 19 Jun 2013:

We get goosebumps because our ancestors used to have much more hair than us. When it was cold, we’d get goosebumps as when we did, our hairs would stand up, creating a warm coat around us to trap air….just like you see little birds puff up to keep warm.

We’ve evolved to lose most of our hair, but the goosebumps ramin!