Book excerpt: This study examines Thomas Aquinas’s contribution to the systematic field of animal philosophy. It applies various models from the current philosophical debate (especially from that concerning the mind of animals) as interpretative aids to tap the potential of the Thomistic approach. Thomas draws a clear line of demarcation between animals and human beings (= anthropological difference). However, he also considers it important to work out the similarities between humans and animals, insofar as they are both so-called animalia, i.e., living beings possessing senses (= animal conformance). His philosophical deliberations concerning animals have a methodological function as well, namely to highlight the distinct capacities of human beings. Thus, for Thomas, the reflection on animals is a key instrument in dealing with anthropological questions.