Adam Clarke on Job 41:29

Darts are counted as stubble - All these verses state that he cannot be wounded by any kind of weapon, and that he cannot be resisted by any human strength. A young crocodile, seen by M. Maillet, twelve feet long, and which had not eaten a morsel for thirty-five days, its mouth having been tied all that time, was nevertheless so strong, that with a blow of its tail it overturned a bale of coffee, and five or six men, with the utmost imaginable ease! What power then must lodge in one twenty feet long, well fed, and in health!