Ethnographic meta-analysis shows that thermoregulation activities predict needle and awl use in North America

Needles and awls are common artifacts in the perishable archaeological record. To understand behavioral motivations for their use, this study examines ethnographic activities linked to needles and awls in North America. We hypothesize that thermoregulation would have been the strongest driver of perforator use. Ethnographies from eHRAF World Cultures are examined to evaluate activity types and temperature effects on the prevalence of perforator use. We observe that the sum of non-thermoregulation activities (69%) account for the majority of ethnographic perforator occurrences. Such activities include tattooing, medical suturing, basketry, and ceremonial activities among others. Nonetheless, the most prevalent activity identified is clothing production, accounting for 14% of ethnographic observations. We furthermore observe from a series of linear mixed-effect models that account for spatial autocorrelation that the probability of perforator observations increases at the coldest temperatures and decreases at the warmest, with a 52% probability of observing perforator tools ethnographically at -35.5°C and a 37% probability of observing perforators where temperatures reach +12.9°C. These results support the hypothesis that thermoregulation, particularly clothing manufacture, was a major driver of perforator tool use while simultaneously revealing that such tools were also commonly deployed in a wide array of activities. Such findings provide insight into the environmental and socio-cultural factors that influenced the use of perforators and thus inform our understanding of an artifact class that is increasingly observed in the archaeological record.