Can dogs be bi?

idk maybe its a dumb question, but can dogs be biual? cuz at this petstore in the mall one time, the let the puppies out in turn in a little pen for people to see and pet them, and one time, there were 2 males and a female, and one of the males [warning: may cause disturbing images =) ] was kinda sittin down, and then grabbed the female and kept pullin her into him and she kept tryin to get a way, and he kept goin bak and forth...idt he was actually doin it but the movement...and yeah...but then she got away, and he grabbed the other male and did the same thing...yeah the other people who saw it laughed too, cuz i doubt anybodies really ever seen that...but yeah, can they b bi?