How do I know if these are ants?

We have several places in our basement that continue to have more and more of this tiny black stuff. I thought maybe it was ants but do they die that quick or is this mouse droppings? The very tiny spectacles are solid black. I found some clinging to the insulation in the basement as well. I do know we have ants outside the basement door but most of it looks dead. What else could this be and what should we do to figure this out.