Recent years have seen a considerable growth in the literature on conceptual issues in evolutionary biology, especially the theoretical and methodological foundations in efforts to reconstruct how species are related to each other. Whereas a few early comparative bioacoustic publications on mammals attempted discussing them. In some detail, much of the growing subsequent literature of comparative phylogenetic studies on vocalization in mammals, especially primates, has largely failed to pay heed to these issues to an adequate extent. A lack of conceptual and methodological precision may impair the testability of the hypotheses brought forward and hence the phylogenetic conclusions drawn. The present contribution calls for a more stringent application of the theoretical and methodological foundations of comparative biology in inter-specific comparisons of vocalizations in mammals and phylogenetic statements based on them. The concept of homology, the evaluation of characters resp. character states as apomorphic or plesiomorphic and the problem of convergent evolution are discussed on the basis of several vocalizations in terrestrial carnivores. It is demonstrated that even on a broad comparative basis it is sometimes not reasonable to make relevant statements.