Different ways of sensing sugars: hummingbirds, woodpeckers and geckos

Animals rely on their sense of taste to detect nutrients and avoid toxins. However, different species can have very different senses of taste: what tastes sweet to humans tastes very different to cats and to birds. Diet shifts happen frequently across the phylogeny of animal species. Changes in diets, for instance, from  omnivorous to carnivorous, can be associated with changes in taste receptor number or function. Understanding how and when taste receptors change gives us insight into how new behaviors arise, how proteins evolve new functions, and into the evolutionary process itself.