All through out civilization, there have been partnerships that have been persay, less than normal. It is interesting to see this affection among different species. In a Kenyan national park, a lioness is known to take in baby Bongo (which is like a desert reindeer or antelope) and even protect it!
The lioness only allows the bongo's mother to come by for nursing purposes only. Unfortunately the lioness kills her victims a couple of weeks later, but she then acquires another customer!