The study, published Monday in the U.S. journal Current Biology, found that penguins have lost three of the five basic tastes -- sweet, bitter and the savory, meaty taste known as umami -- more than 20 million years ago and never regained them.
For these birds, it appears that food comes in only two flavors - salty and sour.
"Penguins are often viewed as a success story of adaptation to a very harsh environment," study leader Jianzhi Zhang, professor of the University of Michigan, told Xinhua. "Apparently there were failures in this adaptation."
Because penguins are fish eaters, the loss of the umami taste is especially surprising, Zhang said.
"Penguins eat fish, so we expected that they have the umami taste genes," he continued. "But for some reason, they don't have them ... we do not have a good explanation."
Compared with mammals, birds are thought to be poor tasters, due in part to the observations that they have fewer taste buds on their tongues and lack teeth for chewing food.
Previous genetic studies showed that the sweet taste receptor gene is absent from the genomes of all birds examined to date.
By Ruchi Singh
reporter
Park Sae-jin
swatchsjp@ajunews.com
