Rib lesions in a prehistoric Puebloan sample from southwestern Colorado

Crania from the Channel Island area of southern California were examined for evidence of traumatic injuries. Well-healed depressed fractures in the outer table of the cranial vault are common in skeletal remains from the northern Channel Islands (18.56% n = 598) but rare in those from the mainland coast (7.5% n = 146). This prevalence of traumatic injuries among the islanders may be a result of intense competition over resources in a geographically circumscribed environment. The frequency of cranial injuries increases significantly between the early and late prehistoric periods on the Channel Islands. This temporal variation appears to reflect changes in patterns of violence associated with population growth and environmental instability.

A maize-based iron- and protein-deficient diet is commonly cited as the most important cause of porotic hyperostosis among American Indian agriculturalists. An alternative to this maize dependence hypothesis is suggested by the analysis of 432 crania from the nonagricultural, fish-dependent population of the Channel Island area of southern California. Cribra orbitalia, a form of porotic hyperostosis associated with iron deficiency anemia, is just as common among these fisherpeople, whose diet was rich in iron and essential amino acids, as it is among maize-dependent agriculturalists. Northern Channel Island crania have much more cribra orbitalia than those from the California mainland. The highest incidence is on San Miguel, a small geographically isolated island with a shortage of fresh water and terrestrial resources. The Indians who lived on Santa Cruz, the largest of the northern Channel Islands with the greatest diversity of terrestrial plants and animals, have less cribra orbitalia than those who lived on Santa Rosa or San Miguel Island. This geographical distribution appears to be explained by island-mainland and interisland differences in water contamination, exposure to fish-borne parasites, and nutritional adequacy of the diet. The prevalence of porotic hyperostosis in a population with a heavy dietary dependence on marine resources shows that among prehistoric American Indians, this condition is not always associated with an iron- and protein-deficient diet of cultigens. It seems likely that high nutrient losses associated with diarrheal disease are often more significant in the etiology of porotic hyperostosis than a low dietary intake of essential nutrients.