Many meat-eating animals have lost their ability to taste sugars, having lost a working copy of a gene that encodes a taste receptor for sugar.
Peihua Jiang and Gary Beauchamp at the Monell Chemical Senses Center in Philadelphia, Pennsylvania, and their co-workers sequenced DNA from 12 members of the order Carnivora, including spotted hyenas and several sea mammals. Seven of the species carried a malfunctioning copy of the Tas1r2 gene that encodes a sweet taste receptor. However, the exact mutations differed from one species to another, suggesting that carnivores have independently lost their ability to detect sugars during the course of evolution.
Furthermore, bottlenose dolphins (pictured) and sea lions lack working copies of the gene encoding receptors for tasting savoury flavours, or umami. Dolphins also seem to have lost a receptor that senses bitter compounds. The authors say taste may not affect what these creatures eat as sea lions and dolphins tend to swallow their food whole.
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For a longer story on this research, see go.nature.com/y4tzk7
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No sweetness for meat-eaters. Nature 483, 377 (2012). https://doi.org/10.1038/483377c
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DOI: https://doi.org/10.1038/483377c