In view of recent developments in human-animal relations, vets and ethicists face a new problem: On the one hand, animals such as mammals and birds are used extensively and are in danger to be reduced to mere production units e. g. in the agricultural production, measuring devices in laboratories, sports equipment etc. On the other hand, biologically similar animals are perceived as family members or partners and are almost treated like humans. The article summarizes the results of a workshop that dealt with reductionism and anthropomorphism in human-animal relations. Vets and ethicists tackled the question how the unequal treatment of biologically similar animals can be better understood and whether it can be ethically justified. In the first section, the problem of inconsistency in human-animals relations is briefly sketched. The second part of the article addresses the ethics of unequal treatment of similar animals in different contexts. The following section inquires possible solutions and the advantages and disadvantages of biological criteria versus social criteria in animal protection. Finally, the background and reasons for our moral intuitions of injustice associated with the inconsistencies in human-animal relations are outlined. This fourth section refers to the presentation of Peter Kunzmann during the workshop on the unequal treatment of equals.The article closes with some general remarks on the issue. One main result of the workshop can be stated as follows: Due to the fact that the various human-animal relations gain their ethical justification from different ethical reasons, the unequal treatment of similar animals in different contexts is not ethically wrong per se. However, every intrusive dealing or interaction with animals is in itself in need of ethical justification.