The flint tools from the Mesolithic layer include microliths — small, geometrically shaped flint pieces that were hafted into composite tools like arrows and spears. The microlith technology of the Mesolithic is strikingly efficient in its use of raw material: by making small, replaceable tips and barbs rather than single large tools, Mesolithic toolmakers could produce effective hunting equipment from a relatively small amount of good-quality flint. This efficiency would have been important for mobile groups who could not always be certain of access to high-quality raw material.
The presence of both hunting tools and food processing debris in the same cave context is consistent with the cave having been used as a habitation and processing site — a place where people lived, at least temporarily, and where they processed and consumed the animals they hunted in the surrounding landscape. Whether the cave was a permanent base or a seasonally used camp is not definitively established for the Mesolithic layer, but the overall pattern of Mesolithic site use in Britain suggests that most groups were mobile, moving seasonally between different resource areas, and that any given site was likely used repeatedly but not necessarily continuously throughout the year.
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## The Significance of Blue Eyes in a Population Context
The eye color prediction for Cheddar Man — blue or blue-green — is in some ways more genetically tractable than the skin color prediction, and its significance is worth examining in more detail.
The genetic basis of blue versus brown eye color in European populations is substantially explained by variation in and around the HERC2 gene on chromosome 15. A specific variant in the HERC2 regulatory region — a change at a position known as rs12913832 — is very strongly associated with blue eye color. Individuals homozygous for the rs12913832-A allele (carrying two copies of the blue-associated variant) have brown eyes in most cases; individuals with other genotype combinations tend to have blue or intermediate eye colors. This is an oversimplification of a genuinely complex system, but the HERC2 variant does explain a substantial portion of the blue-brown distinction, and the prediction accuracy for this dichotomy in the IrisPlex system is high.