things no one knows about animals but you will know today number one swans spend their entire lives with one partner if one of them dies the other often dies slowly from grief number two koalas have fingerprints so similar to humans that even forensic experts can struggle to tell them apart number three when a crow gets injured or is close to death other crows in the flock attack and kill it number four the baramundi is a unique fish it is born male but naturally transforms into a female after 2