The Loch Borralie discovery raises more questions than it answers, and this is appropriate given the nature of the evidence.

The most significant open questions include:

What was the specific purpose of removing the brain?

The skull preparation interpretation is plausible, but it has not been confirmed by the discovery of the skull in a secondary context — a context, for example, that would suggest it had been curated or displayed after the initial post-mortem processing.

The cranial fragments were found in the cairn with the rest of the remains, which is consistent with either the skull preparation interpretation (skull processed, then eventually deposited with the rest of the remains) or a cannibalism interpretation (brain removed and consumed, skull then deposited).

Why were the bones modified into tools and then returned?