[Animals] Why did dogs eat practically everything, but cats didn't?

[FNX Magokiler]

Why are cats such picky eaters while dogs seem ready to gobble up anything that comes their way? It's a question many pet owners probably ask themselves as they convince their feline friend to swallow a pill or remove another piece of napkin from their pup's mouth.

Scientists still don't know a lot about animals' taste preferences. But, thanks to a small but growing number of studies, researchers are beginning to unlock some of the mysteries surrounding the culinary tastes of our four-legged friends. This is what we know so far.

What can cats taste?
If you accidentally drop a muffin on the floor, your dog will probably devour it in one bite. Your cat, on the other hand, may turn up its nose. A possible reason for their different behaviors? Cats do not perceive sweet taste.

Since they couldn't ask the cats directly, the researchers found out by analyzing their DNA. Domestic cats, tigers and cheetahs have a "broken" version of the Tas1r2 gene, which works with another gene, Tas1r3, to enable sweet taste detection. Although Tas1r3 appears to function perfectly in cats, Tas1r2 is an "unexpressed pseudogene" missing 247 letters. Without them, Tas1r2 does not produce a crucial protein needed to form a sweetness receptor in cats' taste buds.

 

 

But if cats can't detect sweetness, what can they taste? Given cats' meat-centric diet, scientists have long suspected that they could taste umami, the rich, savory, meaty taste that the Japanese describe as the "essence of delicious." And recently, they have found evidence that confirms this hunch. After sequencing the feline genome, they discovered that cats express the two genes necessary to form umami receptors in their taste buds, Tas1r1 and Tas1r3.

To take the study a step further, they gave 25 felines a choice between a bowl of normal water and another with umami flavor molecules. As expected, the cats preferred umami water and, more specifically, water containing umami compounds present in tuna. This could explain why cats like saltwater fish so much. "We think umami is the main driver of cat intake," says Scott McGrane, a scientist at the Waltham Petcare Scientific Institute, owned by Mars Petcare UK, which makes pet food and treats: "Tuna hits the spot for umami for cats."

Dogs, on the other hand, can taste sweet and umami. And both cats and dogs have bitter taste receptor genes, although cats have 12 (seven of which are functional) and dogs have 15. What remains unclear, however, is how the number of genes affects bitter taste receptors to the actual perception of bitter taste by animals, says McGrane.

 

https://www.nationalgeographic.es/animales/2023/09/diferencias-perros-gatos-comida-selectivos