They're found in Africa, but not usually in jungles and such. You can usually find them in the dry grasslands, savannahs, and forest edges. They're less likely to be found inside forest areas though.

I've also wondered why they seem to "require" such humidity levels in captivity when they come from a dry area. Either way, my snake is thriving in 60% humidity, so I'm not going to change anything just yet. Maybe I won't freak out as much as I might have before if I noticed my tank wasn't holding humidity well.

I guess as long as they have water to keep hydrated and take a swim when needed, you don't necessarily need high humidity. But it does seem easier for me to just keep the tank at 55-60%.