Natural-trap ursid mortality and the Kurtén Response

Ursid mortality data have long been used to evaluate associations between cave-bear remains (Ursus deningeri and U. spelaeus) and hominin (Homo sp.) remains. Typically, such ursid assemblages produce mortality patterns that indicate that juvenile and old bears died during hibernation, a pattern that is used to suggest that humans and bears occupied the same caves at different times. However, a different kind of mortality pattern can also be used to suggest human influence on cave bears, particularly under circumstances when bears and humans compete for habitat. In particular, data from Lawson Cave and Jerry Long Cave, Missouri indicate that young-adult North American black bears (Ursus americanus) are prone to capture in natural-trap caves. Similar faunal data from Sima de los Huesos in Spain, where cave-bear and hominin remains are found in the same deposit, might also suggest that the bears died from falling into a natural trap. It is concluded that mortality analysis of ursid remains from caves is a useful tool with which to evaluate accumulation histories of cave deposits and relations between humans, artifacts, and cave-bear remains. In particular, ursid mortality data are relevant to the Kurtén Response, a hypothesis reiterated in the recent literature that implicates human encroachment on ursid habitat (e.g., cave den sites) as a potential cause in cave-bear extinction.