Knowledge: Dogs come in many different colors like black, white, brown, red, and more while human hair colors are in blonde, brown, black, orange, red, and grey.

Conversation:
I just have brown hair.  I wonder how many people have brown hair.
Next to black hair, it's actually the second-most common hair color.
Are there different hair colors too?

Response: Yup! Human hair colors come in blonde, brown, black, orange, red, and grey.