Is Sour the First Taste?

Almost all animals can taste, and almost all animals have the same receptors for taste, those for sweet, sour, bitter, salty, and umami (also called savory). The interaction of these receptors help guide an animal to foods that are beneficial to them and away from foods that are not. Scientists are looking into the genetic records to find out how these tastes developed and why. It turns out that no vertebrates have ever lost the ability to taste sourness. It appears that the ability to detect sourness was useful even before animals began judging the usefulness of possible foods they encountered. What's really interesting is the reason why humans are attracted to sourness when other animals aren't. (via Damn Interesting)