Beautifully Carved Antique Hanging Ball in Cage Whimsy (Letter Opener?)

I've just listed a bunch of whimsies all from one source; this one is different. I  found it in New Hampshire and believe it walnut, super finely done and I believe antique. It's a bit of a curious one, too, with tapering end, which suggests use as a letter opener or page turner? And a hanging loop at the other end, which I suppose would allow one to hang it around one's neck, though I'd likely hang it from a nail on the wall instead. Really lovely. 9 3/4" l x 7/8" wide and deep and in excellent condition.