Someone had been processing animal carcasses in or near the caves — not consuming the animals as a natural predator would, but using stone tools to systematically extract the resources that a carcass provides: skin for clothing and shelter, muscle meat for food, tendons for cordage and binding.

The pattern was consistent with what archaeologists call “secondary butchery” — the careful processing of a carcass that had already been killed and perhaps initially processed elsewhere.

Someone had brought animal parts to the caves, or had processed carcasses there, in the specific, systematic way that distinguishes human economic behavior from the opportunistic feeding of carnivores.

Among the 15 confidently identified specimens, two were particularly important for the dating argument: a horse mandible — a fragment of jaw — and a caribou pelvis.

These specimens were submitted for AMS radiocarbon dating, with results that would reshape the Bluefish Caves debate.