The University of Kansas Natural History Reservation is a tract of 590 acres preserved as a natural area, available for the pursuit of ecological studies. The studies undertaken include intensive investigations of selected species of vertebrate animals. The main criteria used in selecting these species have been whether or not they were sufficiently abundant and generally enough distributed to play an important role in the over-all ecology of the area, and whether a species was sufficiently accessible for study with available techniques. Among the 300 species of vertebrate animals recorded from the Reservation, the five-lined skink is one of those most frequently noticed in the field. In actual numbers it is probably exceeded only by the cricket frog (_Acris gryllus_), the leopard frog (_Rana pipiens_), the ring-necked snake (_Diadophis punctatus_), the prairie vole (_Microtus ochrogaster_) and perhaps the white-footed mouse (_Peromyscus leucopus_). Although numerous, the skink is not easy to study because it is secretive in its behavior, and is inactive in inaccessible shelters during the greater part of the year. The five-lined skink generally occurs along with a characteristic set of community associates in a particular type of situation. It is a predator on various small animals, mostly invertebrates. For some of the many prey species the effect is certainly negligible, but for others its predation may be a major ecological factor. In areas where optimum habitat conditions exist its biomass may exceed that of any other insectivorous animal, and in such situations it assumes a major role as a predator and as a competitor with other insectivorous types. In turn it provides part of the food source of various larger predators, including reptiles, birds and mammals. It is a host and carrier of various parasites, including at least one species that regularly attacks humans--the common chigger. It is not evident on the basis of the present findings that the skink is either harmful or beneficial to any perceptible degree, in its over-all effect on human affairs and economy. Nevertheless, there probably are various unsuspected relationships.