It sounds utterly absurd, but researchers have determined that penguins probably can't even taste the fish they gobble up, as they have lost the ability to detect three of the five basic tastes.
That's at least according to a study recently published in the journal Current Biology, which details how a suite of molecular and genetic tests have revealed that penguins likely can't taste sweet and bitter flavors, as well as the savory, meaty flavor known as umami (the same enhancing flavor produced by MSG).
Molecularly, a penguin's traditional fishy meals would be dominated by strong flavors, namely umami. Unfortunately, past research has found that their tongue receptors don't function nearly as well as they should when exposed to extreme cold. The umami, bitter, and sweet receptors in particular practically shut down, leaving only faint hints of sour and salty to enjoy.
The new study suggests, however, that even penguins in warmer climes, such as in a zoo, won't be able to taste their savory fish. That's because most simply lack the genes that would build or empower receptors corresponding to the missing tastes.
The researchers behind the work sequenced the taste-related genes of about 20 different species finding that these animals, who enjoy nuts, seeds, and even small rodents, can taste sweet, bitter, and umami just fine. However, for five penguin groups, the corresponding genes were either gone or broken. (Scroll to read on...)
Experts have long suspected that taste helps encourage a species to eat things that will help it survive, and also helps them identify food that would do them harm. In this way, individuals who can taste more flavors are more likely to survive and reproduce.
However, in a world where that competitive edge is taken away - such as in Antarctica - birds that can't taste bitter things, for instance, would fare no worse than those who have the right genes. This could explain why penguins lack the genes today, as it is suspected their ancestors came from the White Continent.
The researchers stress that this is just a theory. But if they are right, Michael Polito, an ecologist with Louisiana State University, who was not involved with the study, says it wouldn't be a huge surprise.
"Given the way their mouths are oriented, and how they hunt, capture, and consume their prey (often whole), it's not surprising that penguins may have limited taste perception," he told The Verge. "Other senses, especially vision and possibly even smell, may be more important when it comes to how penguins find and identify their favorite foods in the ocean."
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