Leopard - perhaps a 9.3x62 or 9.3x57 loaded with PriviPartisans - very soft and needn't be driven at high velocity to do some incredible expanding.

I'm going out on a limb with Lion - much heavier and heavier muscled but still not far into the vitals - cat's ar tough - shot too many domestics to think otherwise - I'd pack a 300gr.RN Hornady, or 300gr. Interbond from either my .375/06IMP or .375H&H. I'm sure a normal 286gr. Norma Vulcan from a 9.3x62 would work well for both as well.