Comparative Ilithology: The Study of Birth and Parturitional Behaviors Across Species

Birth is one of the most important life history events for eutherian mammals, yet it also remains one of the least understood. Perhaps surprisingly, there is no systematic field of research focused on birth and parturition through a comparative lens. In this paper, we introduce the field of comparative ilithology (named for Ilithyia, the Greek goddess of childbirth and midwifery): the study of birth and parturitional behaviors across species. We outline ten potential new research areas that have historically been overlooked, but which will benefit from comparative study. For each, we provide testable hypotheses and a roadmap for more systematic methodologies and conventions for studying and reporting birth across species. Comparative ilithology has great potential to inform debates around the evolution of human childbirth and inspire novel questions across species surrounding this fundamental life history event.