For decades, scientists have known that cats show no preference for sweets. Then in 2005, researchers at the Monell Chemical Senses Center in Philadelphia published research showing that domestic cats have a mutation rendering their taste receptors unable to bind to sweet molecules. The same was true of their wild cousins, including lions, tigers and jaguars.
Many people were unable to accept this news about their feline pets.
"When we first published the data on cats, it got a tremendous amount of publicity and a lot of people saying, 'My cat likes sweets and you're wrong,'" said biologist Gary Beauchamp, director of the Monell Center. "But invariably they liked ice cream or cake, and sweetness was confounded with fat and other things."
"In retrospect it seems obvious," he added. "But it was to my surprise when we found out that this [loss of sweet taste] has happened repeatedly and independently in many species."
To investigate whether other animals might share the finicky cat's lack of appreciation for desserts, Beauchamp and colleagues analyzed taste receptor genes of a dozen species of carnivores. All of the animals have taste perception systems that are similar to the human system, with specific known genes that code for receptors for each of the five tastes: sweet, salty, sour, bitter and umami.