The understanding of the sense of taste in mammals has over the last few decades slowly changed from the misconception that all mammals are equal with regard to taste to a realization that there are profound differences between species. These differences probably pertain to all basic tastes, but have been especially documented with regard to the sweet taste. This study addresses two issues: the difference in taste fiber specificity between mammals and the related issue of species differences in ability to taste sweeteners. These issues are illustrated by single taste fiber recordings from hamster, pig, rhesus monkey and chimpanzee. The hamster, a rodent, is used as an animal model in taste research because of its especially well developed sweet taste sensitivity, but this study shows that many sweeteners do not taste sweet to the hamster. The same is true for the pig, an ungulate, and from this point of view quite unrelated to the human, but with similar internal anatomy, food preferences and diets, and therefore extensively used as an animal model. Even the rhesus monkey, an old world primate belonging to the same superfamily as human, Catarrhina, shows some differences in its sweet tasting ability and taste fibers specificity although much less so than the previously mentioned species. The only species in which studies of its sense of taste have not yet revealed any differences from the human sense of taste, is the chimpanzee, which by most accounts is our closest relative.