Imagine a world without sweetness, where you couldn’t taste the sugary rapture of cakes, ice cream or candy. This is what it’s like to be a cat. Our feline friends carry broken versions of the genes that build sugar detectors on the tongue. As such, they’re completely oblivious to the taste of sweet things.

So are Asian otters. And spotted hyenas. Sea lions and dolphins too. In fact, Peihua Jiang from the University of Zurich has found that a wide variety of meat-eating animals can’t taste sugars. The genomes of these carnivores are wastelands of broken taste genes.

Two genes are largely responsible for our sweet tooth – Tas1r2 and Tas1r3. They encode two proteins that combine to form a