The theoretical essay discusses the horizontal (cultural) and the vertical (speciesism) dominance of theatre studies, i.e. its Eurocentrism and anthropocentrism. In the context of the global environmental crisis, the essay presents a critique of the field in question and suggests a benchmark of ecological relevance (Glen Love). The fallacies prevailing in theatre scholarship – especially those implicated by the current popularity of the concept of theatricality (Theatralität) and the usage of the term “theatre” to explain other cultures’ phenomena – are shown, and the arguments for transgressing speciesism (Peter Singer) in theatre are presented (animal’s mimesis, mirror neurons, theory of mind, zoosemiotics). Physiological faculties which make Homo sapiens able to perform and understand theatre are discussed in phylogenetic scope, and the interspecies continuity (homology, Ernst Haeckel) is presented as an unconscious archetypal heritage (Carl Gustav Jung, Anthony Stevens). The author argues that a revitalization of katharsis is necessary. The new formulation of the term based on interspecies empathy (Frans de Waal) should extend the boundaries of a community to include non-human individuals. The article concludes that theatre studies should contribute to the reintegration of humans to the wider environmental landscape. Possible ways how to achieve this are discussed.