I have had gerbils and/or hamsters for over 50 years. They have all had the balls to run around in and I've never had one injured. I suppose like anything else in life, there will be a hamster or gerbil who has an accident. I've had hammies and gerbils go off the end of the bed or off a shelf and never get hurt. But I had one gerbil break her leg falling from the top of her cage to the floor. Can something happen to a hammy in a running ball? Yes. Will something happen to a hammy in a running ball? More than likely, No. There are no guarantees. But I do know that all my furries love their balls. I prefer not to give my dwarf hammies run about balls only because the pee in them and wind up a mess.
