Wild animal suffering is suffering experienced by non-human animals living outside human care or control, arising from natural processes. Sources of harm include disease, injury, parasitism, starvation and malnutrition, dehydration, exposure to weather and natural disasters, killing by other animals, and psychological stress. Assessments of scope emphasize the very large numbers affected and the mechanisms that produce it, including natural selection, high-fecundity reproductive strategies (r-selection), high juvenile mortality, and population dynamics.
Religious, philosophical, and literary sources have variously explained, justified, accepted, or criticized harm in nature, with some advocating compassion or intervention and others defending non-intervention or the value of natural processes. Treatments appear in Christianity and Islam, and in Eastern traditions such as Buddhism and Hinduism; in religious contexts, it has been linked to the problem of evil and theodicy. Eighteenth-century figures include Georges-Louis Leclerc, Comte de Buffon, and Johann Gottfried Herder; nineteenth-century discussion features Lewis Gompertz, pessimist philosophers, John Stuart Mill, and Henry Stephens Salt; twentieth-century contributors include J. Howard Moore, William Temple Hornaday, and Alexander Skutch. In the late twentieth and early twenty-first centuries, the topic has featured in scholarship in animal ethics and environmental ethics, including work by Peter Singer, Jeff McMahan, Yew-Kwang Ng, Clare Palmer, Sue Donaldson and Will Kymlicka, Steve F. Sapontzis, Stephen R. L. Clark, J. Baird Callicott, Holmes Rolston III, David Pearce, Alasdair Cochrane, Kyle Johannsen, Catia Faria, Brian Tomasik, and Oscar Horta, in dedicated university and think tank programs, and in the work of advocacy organizations and research institutes.