Interest in environmental protection has grown in business sustainability research and management scholarship more broadly. The emphasis on regulation, market incentives, and the business case, however, has moved the focus away from the natural world, restricting our capacity to understand how environmental protection is seen, experienced and enacted on the ground by organizations interested in looking after nature. In this paper, we report an ethnographic study of Fundo Panguilemu – a regenerative farming enterprise in Southern Patagonia – to show how a unique reciprocal relationship is formed between the organization and non-human animals to restore and protect nature, we call human-animal mutualism in environmental protection work. This unique relationship is organically formed and actively maintained by the founders through three mechanisms: mutual rewilding, relational ambivalence, and task interdependence. Our findings highlight the importance of understanding meaningful human-animal relationships to advance our knowledge of environmental protection and business sustainability more broadly.