Crocodiles have a tendency to retain hard, indigestible objects in their stomach and most crocodiles over two metres long have been found to have stones in their stomach. It is believed that the stones are used as gastroliths (to aid in grinding up food) and that they also may function as ballast (just as in a ship's hull). This tendency for retention of hard objects can also confound coroners' inquests where people have been killed by crocodiles. Along with the human remains, bullets are often recovered from the stomachs of large crocodiles. The bullets usually come from other animals that have been shot and have died, and are later eaten by crocodiles. The animals are digested but the bullets remain.