This research is a composite anthropology of life, assembled from diverse ethnographic engagements with multispecies lifeworlds in Talamanca, Costa Rica. Focusing on four different modes of dwelling in a more-than-human world, the research asks: What happens when peopleâs lives become entangled with, and concerned with, the lives of other species? What kinds of relational configurations arise? How are other-than-human lives, organisms and ways of life conserved, monitored, sustained and reintroduced? What are speciesâ responses to human activities, projects, plans and initiatives? How does the shared experience of a common world affect entanglements between species? What is at stake in entangled lives, and what emerges through encounters between different species? What does this tell us about life as an interspecies experience, about its imperative requirements and the possibilities of reciprocal flourishing? To answer these questions, I use ethnographic film to inspire and inform the entire project. The research is infused with filmic forms of attention to the relational becomings of living beings as they respond to the vital happenings that confront them with the forces and matter of the world. Through film, I explore the longest-term multispecies entanglement in the area, whereby the Bribri people, the largest indigenous group in Costa Rica, are entangled with the forests, valleys and coasts of Talamanca through a range of mundane encounters with other living beings and living matter. Secondly, I engage with a river conservation programme, the ANAI Stream Biomonitoring Programme (ASBP), in which a group of biologists and locals monitor riverine life. I track the work of scientific measurements concerned with riverine species, with their numbers, habitats and future, while rivers emerge as continua and meshworks through which riverine lives become entangled. Thirdly, I explore social life at the Jaguar Rescue Center, a wildlife rehabilitation and reintroduction centre, where humans and wild species learn to live together, cultivating â not without difficulties â the possibility of a future back in the wild, while making the best of adverse circumstances. Finally, I analyse the Ara Projectâs work to breed and reintroduce Ara ambiguus macaws. In particular, I track how encounter value is produced and circulated, how care practices and considerations articulate and contract, and then how the parasitic logic that sustains the project comes into being, redistributing benefits and reinforcing the multispecies association that constitutes the project. In sum, this research aims to enrich the emerging field of multispecies studies by calling for a unifying and adaptive theory of association that captures the ethical, material, semiotic and affective dimensions of conservation ecologies, that is, the multiple forms of vitality that shape human engagement with the lives of other species. The research shows that as species (lives) become entangled through life, to sustain and to conserve become collective enterprises, and it is therefore the multispecies association that comes to matter the most in the pursuit of reciprocal flourishing and sustenance. Relationally emergent multispecies associations vary according to the entities involved, but they always converge on the imperative of life. This imperative is the multispecies shared experience of making a living with and through others, within the given constraints of spatially and temporally specific political ecologies, facing and navigating the uncertainty of life happenings. Finally, this research shows that ethnographic film does not conceptualize, but rather temporalizes and materializes multispecies associations and vital happenings, and can therefore work as an incubator of more extended, inclusive modes of ethnographic attention to, and awareness of, the multiple and concurrent vitalities of social life.