Human beings (Homo sapiens) can distinguish about five major tastes: sweet, salty, bitter, sour, and umami. These tastes are just the beginning, however. Each sensation tells an important story in human evolution. Of course, each taste has both healthy and unhealthy foods associated with it!

A sweet taste can signal the presence of sugars and other carbohydrates. Carbohydrates are essential for providing and storing energy. Salty foods usually signal the presence of sodium. Sodium is an element necessary for maintaining our bodies’ water balance and circulating the flow of blood and nutrients. Bitter tastes can signal the presence of toxins, many of which are unpalatable. A sour taste can signal the presence of acids. Acids may indicate that food is spoiled and no longer healthy. Umami is a savory or “meaty” taste. Umami can signal the presence of proteins, which perform an array of important cellular functions in our bodies.

Use our video, part of the National Geographic Channel series “Eat: The Story of Food,” and read through our questions to think about your own tastes. Then, think about what an animal tastes! Although all mammals have a sense of taste, the flavors they detect can vary widely. As Michael Pollan, an author in the video, says: “If you’re a koala, you eat eucalyptus. If it’s not eucalyptus, it’s not food!” Read our Fast Facts to learn more about what animals taste.