Bones are greatly affected by gravity, and arc similarly to Throwing Knives and Shurikens. Of these three consumable throwing weapons, Bones have the least range (Throwing Knives having the greatest). When used as weapons, Bones have a 50% chance of being retrievable after use, even if they hit enemies.
The Skeleton Merchant will use Bones to defend himself if needed. The bones thrown by him are not retrievable.
In Expert Mode, Skeletons can throw bones at the player, making them far more dangerous.
Since Bones are used as ammo by the Bone Glove, they can be stored in the ammo slots of the inventory.
On the Desktop version, bones can no longer be stored in ammo slots due to the Bone Glove being changed from a ranged weapon to an accessory. Any bones placed in the ammo slots prior to the update will still be located there.
While it may appear that ordinary Bones do more damage than the Bone Glove, the damage from Bones used as ammo is added to the Bone Glove's damage.