Carceral geography, whilst in dialogue with many aspects of theory-building in contemporary human geography, including notions of affect, mobility and embodiment, has yet to meaningfully engage with animal geographies to consider the nonhuman dimension of carceral experience. Likewise, criminological scholarship of human-animal carceral co-presence has yet to progress far beyond the consideration of animals as mere 'signifiers' of human endeavour and meaning. Further, the study of prison animals has thus far considered only those nonhumans intentionally present in carceral space, such as therapeutic animals, eliding completely those considered 'vermin'. This paper broadens the scope of extant scholarship, considering the parallels between the discourses of the 'rehabilitation' both of prisoners and prison animals during incarceration, and of both the prisoner and the prison animal as abject.