Hey. Can dogs be gay?

I found my neibors dog blackjack in our yard and we left a note saying we had her. Shilo my boy dog was outside and felt uncomfertable so i went out thinking that he was just nervious but when i looked to see if blackjack was a girl like i always thought. He was a boy. He kept trying to hump Shilo. So is it possible for a dog to be gay???