They are not natural formations but deliberately excavated spaces, which immediately raises the question of who made them, and why.

The caves attracted the attention of a researcher named Martin in the early 1930s, who recorded finding a large quantity of broken flint inside one of them. What struck Martin was how closely these flints resembled material recovered from raised beaches elsewhere in Ireland. Raised beaches are ancient shorelines left stranded above the current waterline after the land rose following the retreat of the last ice age, and the flint assemblages associated with them tend to point towards early prehistoric human activity, when people worked stone into tools along coastlines that no longer exist at their original level. Whether the flint at Bride's Head arrived through the same processes, or tells a similar story of early habitation, was not resolved. Traces of flint have also turned up at the site in more recent times, suggesting the material is not exhausted and the question remains open.