Actually, you raise a possibility.. Certain rats like to collect objects (preferably shiny ones) Hence the term, pack rats. Don’t know if rats had access to that cave but good point.
“Archaeologists baffled by ancient rat droppings found near tiny Swiss ring watch.”
Yep, they’re called packrats. Ask me how I know?
...time travel is documented in the bible, the just don’t say it in those words!