This thesis examines the work and lives of a community of biodiversity-centered, rubber-boot oriented biology students and researchers at the Department of Bioscience at Aarhus University in Denmark. Based on long-term immersive fieldwork, it depicts practices and animations that are attuned to the earthly vulnerabilities of our time and at the same time permissive of lived enchantment and hopes for the future. It charts, in other words, how a love of the living turns into a quest for a world that is not just biodiverse, but where the bios as a whole, not the Anthropos alone, becomes the gravitational center of everything that humanity does and does not do. This vision is for the world is what I refer to in this thesis as the Biocene. The first part of the thesis concentrates on central elements of biological practice at the Aarhus University to explore how such practices implicate passions and condition relationships to the living world. The latter part shifts beyond the institutional con-fines of the university to focus on the ways that biology – at least of the rubber-booted sort – emerges as something like a calling. Chapter 1 examines taxonomic practices of classification and identification of species. It queries how such presumably detached approaches may bespeak care, and argues that classificatory exercises, apart from providing a grip on a diverse natural world, augment the lives of my interlocutors. Identifying a species by a name, I suggest, is not like putting a label on a container of rice. Nor is it only a constitutive operation of power. Rather, it makes particular species of bees, ants, or grasses pre-sent and manifest to biologists, thus enabling certain care-full relationships to the living world. The second chapter exposes the ethicalities involved as biologists forfeit nonhuman life both in- and outside laboratories. It demonstrates how biologists try on various legitimizing institutional logics, highlighting how such frameworks fail to address the full gamut of ethical becoming that is at stake. Ultimately, I suggest, violence and killing executed by biologists is realized in an ethically engaged mode of apolo-gy whereby biologists accede to the complexity of entangled multispecies relationships and take on responsibility for their actions in order to nurture the care-full po-tentials of responsivity. Chapter 3 tackles the doing of biodiversity through a turning toward wild(er) nature in general and rewilding in particular. Taking the rewilding experiment at the Mols field laboratory as its point of departure, it argues that rewilding among biologists is ar-ticulated as an effective biodiversity management tool but also, importantly, that it presents a vision for the natural world that revolves around a decentering of Homo sapiens. This decentering, I argue, constitutes a condition of possibility for a detachment from pecuniary human interests which, biologists contend, ought to structure human relations to the rest of the living world if earthly flourishing is to be dis-tributed more evenly across species – and if we are to properly appreciate the diversity of the bios on its own terms. Chapter 4 reveals how such experiences of decentering are inhabited and lived by my biologist interlocutors. It depicts various encounters with life – with evolutionary theory, with sei whales and wolves – that leave biologists infatuated and ‘wonder’ed,’ and it suggests that such infatuation hinges crucially on the skills and wherewithal of rubber-boot biology. The fifth and final chapter focuses on the flipside of such infatuation and begins with the grief and mourning that comes with the realization that one’s object of love is hurting and may soon cease to exist. I propose that these diverging affective responses coalesce in an incipient mobilization of biologists into various kinds of concerted interventions in favor of biodiversity. Zooming in on instances of con-spicuously excited public biodiversity dissemination, I illustrate how my interlocutors seek to instill in the general public greater attention to and appreciation of the (often unloved parts of the) living world. I suggest that as they do this – as they become what I call machines of wonder and enchantment – enchantment is turned from a potential source of ethics to a form that ethics or politics might take. The five chapters present distinct thematic loci and they demonstrate how biodi-versity comes to matter to my interlocutors in ways that are 1) experientially aug-menting, 2) ethically absorbing, 3) cosmologically unsettling, and 4) wonder-full. Indeed, I make the case that such forms of mattering fuel my interlocutors’ quest for a Biocene. Given our ecologically perilous times, vernacularized among other things as the sixth mass extinction, we might want to take notice.