Interesting, I have never read about natural hybrids, I wonder if someone was doing a little weird crosses. I would suggest looking into Ligers and Tigons. The liger is a male lion/female tiger, it is bigger than both, a truly formidable hunter if ever introduced in the wild. The tigon is a male tiger/female lion cross (note, much harder to produce as a male tiger is more discriminating than a male lion). A tigon gets the worst of the deal, smaller in all respects.