This research examines contemporary performance as a framework of engagement with the nonhuman world. It investigates how artists are using performance strategies in artistic contexts to more ethically encounter nonhuman animals, challenging anthropocentric relations that perpetuate speciesism and other interconnected forms of human oppression. This ethical enquiry examines power imbalances in human-animal relationships, advocating for a new approach to ethics that addresses these inequalities. From an intersectional feminist perspective particularly informed by posthuman / new materialist feminist thought and Black feminism, this thesis proposes that contemporary performance can serve as a site to enact an ‘interspecies feminism’: a non-anthropocentric ethics of difference-in-relation, grounded in affirmative practice. This argument is predicated on the premise that how ‘we’ relate across species-difference is becoming increasingly urgent in the context of overlapping social and environmental crises. Employing a performance ethnography methodology in conjunction with feminist theory, this thesis performs a feminist posthuman cartography (Braidotti 2019a, 2019b), mapping the dynamic forces of power (entrapment and empowerment) in situated human-animal relationships. Through the analysis of a diverse selection of artist case studies engaging with actual animals in performance, this research asks: what strategies are contemporary artists exploring for a more ethical inclusion of animals in interspecies performance practices? How are contemporary artists navigating and negotiating shifting power dynamics (entrapment and empowerment) through interspecies performance? How might contemporary performance contribute to an interspecies feminism - an intersectional and non-anthropocentric feminist ethic inclusive of nonhuman animals? Presented in three ‘acts’ – On Land, At Sea and Of Air – this research interrogates how each case study uses performance approaches to inhabit interspecies relations otherwise. This includes land art collaborations with draft animals (Ruth K. Burke); dancing with wild dolphins (Dolphin Dance Project); singing with humpback whales (Michaela Harrison); swimming with jellyfish Norway (Elly Vadseth); and performing falconry (Raja’a Khalid).