Is my gerbil just showing his dominence?

Question

i put my 2 male gerbils, which i have had for about 2 months now, in the bath tub to play my black gerbil rolled my other gerbil on his back and pinned him down, the other gerbil didnt struggle or anything my other gerbil rolled over and got back on his feet again, then my black gerbil started humping him for about a couple of seconds the other gerbil ran away and my black gerbil was running faster then i have ever seen him run, he was going crazy darting all over the place they where in the same cage when i bought them at the petshop and they have been in the same cage in my house for as long as i've had them, is the black gerbil just showing his dominence or did i interupt something? (supposedly they where both males and i've only seen the black gerbil pin the other one it is the first time i've seen him hump the other one though, and the males and females where already seperated in different cages at the pet shop)

Answer 1

http://www.gerbilbreeding.com/sexing.htm

check that the bottom male than if there not have the male man hood remove or split them. if there bottom male than if fine it this dominence

Answer 2

yes mine did that. they are establishing the alpha-gerbil :)