One of the things I really love about carved wooden whimsies is their infinite variety, even with the most straight forward of forms. I think this may be the largest ball in cage I've seen at 3 x 3 x 3 inches, with a ball so large it seems poised to bust out of its cage entirely! This one I'd guess dates to the mid-20th century or so, and reads as much as a tabletop minimalist sculpture as a folk art carving. 

There is a split in one side of the cage as pictured. Otherwise very good condition. The ball is a tight fit but does move.