The elephant and the peacock started off life together. They were grown from one seed and seemed the same. Then nurture kicked in. And no one was sure if they were the same or twins. They developed their own identities, their own personas, and had completely opposite outlooks on life. And when asked to explain they said "I just grew that way."
The peacock sometimes got peeved when he was mistaken for the elephant's tail. The elephant sometimes got irritated when the peacock's feathers tickled his ears. But they'd both gotten used to it over the years.