This is about the science – which is about the genetics of all the cat species – behind the failure of cats to detect sweetness in their food. We know that cats can’t detect the taste of sweetness in their food but what happened? It is a bit strange when you think about it and I have described it as a failure in the skills of the cats. It is important to note that this issue affects all the cat species of which there are 36 or 37 (or even more depending on your point of view on taxonomy).
The genetic reason for this ‘failure’ is what I’d describe as a genetic mutation which occurred very early on in the evolution of the cat species before they branched out into different lineages. This must have been the case as it affects all cats (all members of the Felidae family) as mentioned.
My reference work on this topic is the excellent book Small Wild Cats by James G Sanderson and Patrick Watson. I think I’ll quote them as it gets to the nub of the matter. Here is the genetic reason why cats can’t taste sweetness:
In 2005, scientists discovered that all cats lack one of a pair of proteins required to sense sweetness. The missing protein was the result of a deletion, the loss of part of a chromosome or sequence of DNA in a gene.
Sanderson and Watson
This mutation ‘prevented one of the proteins that enables the perception of sweetness from being expressed (created)’.
My AI friend “Poe” says this about this genetic deficiency:
Lack of Sweet Receptors: Unlike humans and some other animals, cats lack the taste receptors known as “T1R2” and “T1R3,” which are responsible for detecting sweetness. These receptors are present in humans’ taste buds and are activated by sugar molecules. Without these receptors, cats are unable to perceive the taste of sweetness.
Poe – thanks Poe.
Sanderson and Watson suggest that this early mutation might have caused the cats to become obligate carnivores as they could not enjoy eating plants which contains naturally occurring sugars such as sucrose due to photosynthesis. As a consequence, the cats developed a taste which was refined over the eons for the flesh of animals. As Poe states: “Cats have a heightened sensitivity to amino acids, which are the building blocks of proteins. “
Cats can detect bitterness. It is believed that this is a survival skill also evolved over millions of years as toxics often taste bitter. Cats reject bitter foods on the basis that they are toxic or poisonous.
That, then, is the genetic science behind the Felidae’s inability to taste sweetness.
Briefly turning to humankind! I think humans would not be suffering from an epidemic of obesity in many countries, specifically the developed countries, if we, too, had lost our ability to taste sweetness. Humans have become almost addicted to sweet and salty foods. The food manufacturers add far too much sugar and salt to processed foods to make it more saleable at the expense of our health which is a cynical but expected approach from commercial enterprises.
Separately the cat’s tongue is an amazing organ. Below are a couple of articles on it. There are more on this website. Please use the search facility on the page to find them. Or use the pagination below the links.
RELATED: 2 different types of backward facing papillae on the domestic cat’s tongue
Finally, in terms of the use of the English language the following sentence is grammatically incorrect in my view: “Why can’t cats taste sweet?” I have seen this a lot on the internet. It seems that writers struggle with the word ‘sweetness’ which is the opposite to ‘bitter’ or ‘bitterness’.
