Plenty of players have been disgruntled by the aging lines on lions as they age. My solution to prevent that is this;

An item in the oasis that prevents all of your lions from getting those ugly aging lines. It would work like the extra cub stages; for your whole pride. 10 GB just like the cub stages, also?

Or

An item that will prevent aging lines in ONE lion, not the whole pride. One 'Anti-Wrinkle Cream' = one young looking lion.