Depends on how long they’ve been dead and the conditions. I attended an autopsy of a relatively freshly dead man, and it smelled a LOT like pee bc the bladder was decomposing and it was VERY full. Cadavers that have been preserved for dissection smell VERY strongly of phenol because they are embalmed in a stronger fluid. It’s so strong that it burns your eyes and mucous membranes. When someone is reduced to bones and no soft tissue, if they still have some marrow, they can be greasy and smell a lot like rawhide. Once the bones are fossilized or just have no more organic material, they don’t smell at all!