Are 5 round AR mags required for varmint hunting?

[theGinsue]

Those big cats scare the doodoo outa me. They can stalk you for hours without you even knowing they're there.

As I understand it, when hunting mtn lions, most folks usually use dogs to tree the cats (which is why you hear about them getting shot in trees). Having plenty of dogs is the only way I'd want to pursue one of them.