Why do girl dogs hump?

Question

My fixed, female, cocker spaniel is constantly humping my fixed, male, cockapoo. Where would she even get this instinct from? She's a girl and fixed at that.

Answer 1

That is how wild dogs and wolves, which are descendants of dogs, establish their dominance.

Answer 2

It's dominance. She's showing HIM who's boss.  

Answer 3

she's just playing ,at least there's no danger of puppies !!!

Answer 4

it's not humping, it's a display of dominence. she thinks she's the alpha female and she's letting the male know that she's in charge.

Answer 5

usually its a sign of dominance.