CRANIAL EVOLUTION OF COMMON RACCOON (PROCYON LOTOR) IN THE ANTHROPOCENE

Commensal animals—those that live in urban areas—contend with an environment that is drastically different than that of their recent ancestors. With such abrupt environmental change, one might expect commensal animals to be in the midst of a similarly abrupt punctuated equilibrium of morphological adaptation. Procyon lotor, the common raccoon, is a commensal animal that is able to survive in the most urban and rural environments, and has existed in these unique niches for a long enough period of human history to suspect measurable adaptations. Therefore, a morphometric comparison between these populations may provide insight into how Procyon lotor is evolving in response to urbanization in the Anthropocene. It is expected that commensal raccoons will exhibit reduced dentition, as scavenged human food is typically processed and easier to ingest. It is also expected that thriving in this novel environment demands higher cognitive function, which may be measured by the relative brain size of either population. Dental and cranial measurements were taken from specimens collected from both urban and rural environments, and an analysis of variance was used to infer potential selective pressures that are shaping and will continue to shape commensal animals in the Anthropocene.