Specialization and phyletic trends of sweetness reception in animals

During the last decades, the comparison in various animal species of their gustatory responses to compounds eliciting a sweet taste in humans has extended our knowledge of the great biodiversity of the taste responses and evidenced some specialization and/or phyletic trends within species. Our interest was focused on responses to natural sugars, polyols, and naturally occurring sweeteners, but also on various artificial sweetening compounds, including the very powerful guanidine sweeteners. New results obtained with kangaroos-which originated about 130 MYA-have shown that their sweetness receptor is not designed to taste any of the artificial sweeteners tested. Therefore, the ability to taste complicated artificial sweeteners must have evolved later in higher developed mammals, about 100 million years ago.