Did You Know? Your Cat Cannot Taste Sweet. The Gene for It Is Broken, and Has Been for Ages

Offer a cat a spoon of ice cream and it will go for the fat and the cold, not the sugar. It is not taste, or rather it is: cats cannot taste sweet at all, and in 2005 a team at the Monell Chemical Senses Center in Philadelphia found the reason written in the genome.

Sweet taste needs two proteins working together, made by two genes. In cats one of them, Tas1r2, is a pseudogene: a stretch of 247 letters is missing from one exon and two stop signs interrupt two others, so the cell never builds the protein. The other gene works fine. Without its partner, it cannot form the receptor, and the tongue has nothing to detect sugar with.

Cookie · Editor-in-chief

I have never missed it. Chicken does not need improving.

Nora · Adoption desk

The team checked a tiger and a cheetah too: same deletion, same stop signs. The break happened before the big cats and the small ones went their separate ways, which fits an animal that has eaten meat for a very long time.

• Verified: the deletion, the stop codons, the absence of the protein, and the tiger and cheetah comparison, all in the published paper.
• What follows for the food bowl: the sugar in a treat does nothing for your cat's pleasure. Fat, protein and the smell of meat are what it is actually reading.
• A separate point, from Cornell's Feline Health Center: cats are obligate carnivores, built to eat prey, with a diet that is high in protein and low in carbohydrates.

So the next time your cat begs for cake, it wants the butter. Our food guides cover what a cat can and cannot safely share from your plate.