Abstract: This paper examines the use of predator fences for conservation in Australia. It argues that these major infrastructures for enclosure act as a form of 'provocative containment' in which particular forms of nature are not simply protected but made to happen. The primary focus is Newhaven, a property in remote central Australia managed by the Australian Wildlife Conservancy, a non-profit organization with the biggest estate of privately managed land for conservation in the nation. At Newhaven, the first stage of an ambitious and expensive predator fencing programme has recently been completed, with a second phase under construction that will see the property become the site of the largest feral cat-free enclosure on the planet. In analysing this significant material infrastructure, and the practices and discourses that the Australian Wildlife Conservancy deploys to both justify and attract funding for it, it is possible to see a new conceptualization of conservation emerging in which nature is not simply offered sanctuary but actively stimulated and simulated. The Newhaven fence is much more than a passive material boundary between desired and undesired life. It is a reality-generating device with complex and contradictory biopolitical effects. The concept of provocation highlights how the fence emerges as a deliberate intervention into the dynamics of life. We examine how this is done in four distinct ways: through the sociotechnical design and construction of the fence as 'cat-proof', by enrolling Indigenous labour and tracking skills to kill cats, through the use of ecological surveys and baselines to make some life calculable, and via the translocation of species in order to allow them to be both protected and flourish. Each of these practices is essential to making new natures at Newhaven through the complex dynamics of provocation and containment. The issue is: what sort of nature?