Dear David Wynick,
That was a really fast answer (http://www.askabiologist.org.uk/answers hp?id=7628), thank you! Though, I don't think if you took a peek on the videos I linked.
2 out of the 3 videos takes place in the wild, and neither the lioness or the leopard has lactation or lost their offspring. I know these are individual cases but since wildlife is not monitored as intensively as domestic animals, you cant be sure how often this happens. What is sure that this happens and can't be explained involving fitness or natural selection.
Evolution has its set of rules, it is an algorythm. It is a hill-climbing heuristic (greedy algoryhm) aplied on a population and mixed with random mutation. In theory, nothing can exist in nature that cant be derived from this algorithm.