A case for reduced skin sensation in high latitude prehistoric Polynesians

The cranial sensory nerve supply in three skeletal populations, two distinc t prehistoric Polynesian groups from New Zealand, the Moriori and Maori, an d one contemporary Indian group, are investigated. This paper assesses an a spect of the hypothesis that Polynesian groups have anatomical adaptations that enabled them to survive in a cool and wet environment. To this end the relationship between sensory nerve dimensions were examined, based on the area of cranial nerve foramina, and external environmental temperature. Sta tistical comparisons between the Polynesians and Indians showed significant ly reduced cranial cutaneous sensory nerve foramina size, and therefore dim inished facial cutaneous sensory nerve supply in the Polynesians. On this b asis it is inferred that sensory supply to the skin of the infracranial bod y was also lessened. This paper proposes that reduced skin sensory nerve su pply was selected as an adaptation to a cool and wet environment, where it acted as a body energy conserving mechanism by delaying the onset of body w arming mechanisms.