Interpretation of the “lagomorph index” in the American Southwest

Various forms of the “lagomorph index” (LI) have been used to examine the ratio between cottontail rabbits (Sylvilagus) and jackrabbits (Lepus) recovered from archaeological sites in the American Southwest. Some indices incorporate arithmetical problems. The LI should be standardized as the number of cottontail specimens divided by the sum of cottontail plus jackrabbit specimens. A number of hypotheses have been developed to account for variation in LI values, focusing on human modification of the environment and human predation decisions. We examine values for this index in the northern Southwest and show that they differ from similarly calculated values in the southern Southwest. We argue that human land management practices had different impacts on northern and southern landscapes, and that proportions of cottontails and jackrabbits reflect these differences.