Animal welfare science and ecology are both generally concerned with the lives of animals, however they differ in their objectives and scope; the former studies the welfare of animals considered ‘domestic’ and under the domain of humans, while the latter studies wild animals with respect to ecological processes. Each of these approaches addresses certain aspects of the lives of animals living in the world though neither, we argue, tells us important information about the welfare of wild animals. This paper argues (...) for the development of a new scientific discipline ‘welfare biology’ to address these issues and more, given the deficiencies of pre-existing life science disciplines to research the subject. Welfare biology is the study of the welfare of all living beings who have a welfare, with a value orientation toward promoting that welfare, regardless of the beings’ situation or relationship to humans and our activities. (shrink)