Penguins are famous for engaging in animal homosexual behaviour. They even sometimes steal eggs from heterosexual couples and rear the youngs. A famous case at the NY zoo, and reports in zoos from all over the world have confirmed that not only are homosexual couples frequent, but the bonding between the gay partnersis strong . Case in point: a zoo in Germany tried importing Swedish chicks and even they couldn't lure the males away!
Penguins are also known to prostitute themselves for a rock. They will let other penguins exchange sexual favors for nest building material.
Penguins sometimes engage in inter-species sex. Perhaps unwillingly. sometimes sexually frustrated seals molest penguins on the beach. I am not even making that stuff up!