They don't have pilots in the traditional sense, ie someone with with any sort of qualification that would allow them to fly a manned helicopter or aeroplane. They're trained specifically as UAV operators. Unlike pilots of manned aircraft, they also often come from the enlisted ranks.
Getting a bit off subject, but thats not entirely true. Larger UAVs (think Preds/Reaper and larger) are still flown largely by traditional pilots (I think the USAF has dabbled in using non aircrew officers to fly UAVs, but they still get trained up to at least PPL level). Certainly the Americans, Brits, us and even the Canucks use qualified pilots for there larger UAVs.
Smaller tactical UAVs (from 'backpack' UAVs up to ScanEagle size) are not usually flown by qualified pilots. Australian ScanEagles were flown by artillery corps troops. God help us all!
As far as enlisted ranks vs officers being pilots, well there was no problem doing that during WWII, and even now the US Army uses Warrant Officers as helicopter pilots, but thats a whole other argument thats been done to death over on the Military Forum.