GEE, WHY DOESN’T MY CAT LIKE CAKE? IT’S SOOO YUMMY!
While it might have made a good story involving cats as the official “tasters” to suss out poison on the plates of royalty in the past, it turns out that these bitter taste receptors did not evolve to protect them from ingesting poisonous plants with bitter tastes. Unlike sweet tastes, which has only one or two different receptor types, the number of functional bitter taste receptor types varies greatly across species, the release explained. If bitter taste receptors evolved primarily to protect animals from eating toxic plants, then one could expect to find several functional bitter receptors in herbivores. However, since the researchers found that cats which only eat meat also had several bitter taste receptors, their study contradicts this long-standing belief. This does suggest that cats are sensitive to bitter tastes, which may help explain why they are such picky eaters.
“Alternate physiological roles for bitter receptors may be an important driving force molding bitter receptor number and function. For example, recent Monell-related findings show that bitter receptors also are involved in protecting us against internal toxins, including bacteria related to respiratory diseases,” Gary Beauchamp, author of the study and a behavioral biologist at Monell, said in his statement.
Generally speaking, an animal’s sense of taste helps it to distinguish nutritious foods from potentially harmful or toxic options. For instance, sweet foods such as fruit contain sugars that are an important source of energy. When animals eat these foods they associate them with being tasty and prefer to eat them over bitter tasting foods, such as are present in most poisonous plants. But carnivorous cats have evolved without the gene needed for sweet taste receptors since they have no need to detect sugars. This evolution is consistent with other carnivorous mammals, including sea lions and spotted hyenas.
“Cats are known as picky eaters,” Peihua Jiang, leader of the study and a molecular biologist at Monell, said in an official statement. “Now that we know that they can taste different bitters, our work may lead to better formulations of cat food that eliminate the bitter off-taste associated with certain flavors and nutrients.”
Based on their results, researchers have concluded that the number of bitter receptors an animal has is not directly related to the extent to which they do or do not consume plants. However, bitter taste could still act as a protective measure to make sure animals are not consuming toxic substances from the skin or other parts of certain prey species, including reptiles, amphibians and invertebrates.
The findings were recently published in the journal PLOS ONE.