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Penguins, it has been discovered, cannot palate the sweet or savory flavors of their foods of choice. For the waddling, artic-dwelling birds, foods come in just two flavors – sour and salty– according to a novel study, published in the current issue of the journal Current Biology.
Jianzi Zhang, a researcher at the University of Michigan and co-author if the study, stated that penguins consume fish, so you would assume they would need the umami receptor genes in order to discern the tastes of different sea treats. Though, for some reason currently unknown to scientists, they do not possess them. He explained these findings are unexpected and perplexing, no explanation can be surmised for it. Nevertheless, he said they do have a few ideas as why.
Zhang and his research team got the determination to search for an answer by sequencing the genomes for emperor and adelie penguins. The team was surprised they could not locate any rudimentary palate genes. Therefore, they took a closer look at penguin DNA. After finding nothing in the DNA, insofar taste receptors would be necessary for penguins, they determined that all species of penguin lack functional genes for the receptors for bitter, sweet, and umami tastes.
This may be obvious, considering penguins are not chowing down on sugar-sweet lollipops or umami-laden soy sauce, he explained. The researchers claimed the reason for the loss of genes is most likely due to the temperatures in their environment, rather than the sustenance of the penguins.
Gene-based taste receptors for bitter, sweet, and umami flavors are temperature sensitive, they found. Taste receptors do not work if food is cold or is eaten in a frigid environment. This is the reason why people cannot taste the flavors in ice cream very well after a while. Exposure to cold inhibits taste buds, as well as olfactory sensors, thus leading to the decreased sense of taste.
Zhang explained the penguins, including their early ancestors, probably possessed all normal taste receptors found in other animals, but lost them after they migrated to colder environments. In the study, Zhang and his research team experimented with all species of penguin, including those found in warmer environments, like the Galapagos penguin. They found since all penguins are ancestrally rooted in Antarctica, all species of penguin are genetically hardwired, taste-wise, for consuming food in a colder environment.
They expect that since penguin tongues are most adapted to grabbing onto cold, slippery fish, with their sharp papillae appendages, the notion of tasting different types of food is irrelevant. However, Zhang said there is no need to be apologetic towards the waddling, wayward, water-fairing birds, since they eat their food whole, there is no need for them to savor the taste of fish. After all, penguins are not arbiters of tasty seafood.
Zhang explained their research shows that penguins, considering their tongue structure and feeding habits, need no taste perception. Although, they have yet to find whether these characteristics are a cause or consequence of sensory loss, they doubt the penguins notice or even care.
By: Alex Lemieux
Picture: Tambako the Jaguar – Flickr License