We humans will never tire of seeing two very different animals cuddling, nuzzling, or just hanging out. While our species is mostly limited to befriending our own kind, the sky's the limit in the animal kingdom. Their bonds transcend the boundaries that we normally face (language, culture, class, social ranking, etc.), making their friendships more pure and totally worthy of celebrating. No matter the difference in appearance and size, mammals will befriend birds, predators will befriend their prey, and even cats and dogs — the most extreme of arch nemeses — will find their way into each other's arms.