In the early middle ages, a community of Irish monks constructed a monastery outpost on the lonely Skellig Michael just offshore of County Kerry. These skelligs served as a mysterious boundary land where the known met the unknown, the worldly wrangled with the spiritual, and the very parameters of humanity itself were brought into question. Amid a period of great transition in Irish society, the monks willfully abandoned the luxuries of developing Western civilization on the mainland (and on the continent more broadly) to test their endurance through religious asceticism on a craggy island more suitable to birds than bipeds. This article reimagines the Skellig Michael experiment as a liminal space, one that troubles premodern efforts to disassociate from animality in an era when “human” and “animal” were malleable concepts. As Western society transitioned from animist paganism to anthropocentric Christianity and Norman colonial control, the Skellig Michael outpost (which survived into the 1300s) offered a point of permeability that invites a critical rethinking of early Irish custom. This article applies theories of liminality and Critical Animal studies to address the making of “human” and “animal” in the march to “civilization,” arguing that species demarcation and the establishment of anthroparchy has been central to the process.