Observations on seasonality and mortality from a recent catastrophic deathassemblage

On 3 November 1991, a group of 150 pronghorn went over a cliff near Green R iver, Wyoming. This mortality site provides a unique opportunity to examine a number of characteristics of catastrophic death assemblages that may aid in the interpretation of archaeological bonebed sites. In 1993, the mandib les were collected for a study of seasonality and age estimation. Examinati on of seasonality revealed some variation in estimates by eruption/wear and cementum increments. Six percent of 86 fawn specimens exhibit eruption and wear more advances than expected for a November third event, and 21% of 27 cementum increment estimates by eruption and wear reveal a distribution of pronghorn ages with many more juvenile animals than expected for a known ' catastrophic' event. This may be explained by the patter of seasonal huntin g in a modern managed herd, which is likely to be very different than abori ginal hunting patterns. Age estimates by eruption/wear and cementum increme nt techniques failed to agree within six months in 58% of 29 test cases, wi th a tendency for cementum ages to be younger in 71% of specimens in which estimates of age differed. In general, the mandible assemblage exhibited mo re variability than one might expect for a single catastrophic kill event.