Introduction
Cats are known for their love of all things meaty and fishy. So why do some cats also seem attracted to sweet foods like ice cream or cake? Many cat owners have witnessed their feline trying to sneak a lick of their dessert. Yet it’s commonly said that cats can’t actually taste sweetness. So what gives? Why does your cat go crazy over your bowl of ice cream when they’re supposed to only crave meat?
The truth behind cats and sweet foods is more complex than it seems. While it’s true that cats lack the same sweet taste receptors as humans, they have still evolved their own unique ability to detect and respond to sugars and carbohydrates in potential food. Understanding the science behind feline taste buds can help explain why your cat may enjoy sweet flavors, even if they experience them differently than we do.
Anatomy of Cat Tongues
A cat’s tongue contains tiny barbs called papillae that are shaped like hooks or spines. These papillae give the tongue its rough, sandpaper-like texture and allow cats to groom themselves effectively. The papillae also play an important role in a cat’s ability to taste.
Cats have taste buds located on the papillae on their tongues. Each taste bud contains 50 to 100 taste receptor cells. These receptor cells detect chemicals from food and connect to nerves that send taste signals to the brain. The abundance of papillae gives cats more taste buds than humans. A cat’s tongue has an estimated 470 taste buds per square centimeter compared to only 9 taste buds per square centimeter on a human tongue.
The structure of the papillae allows cats to scrape meat from bones and lap up liquids efficiently. The hook-like nature of the papillae gives cats a rough tongue that can rasp meat off bones and scrape clean fur during grooming. The papillae also help cats lap up water, as they act like a tiny spoon to collect and carry water into the mouth.
Taste Receptor Genes in Cats
Cats have fewer functional taste receptor genes compared to most mammals, including humans and dogs. According to research by Li et al published in PMC, domestic cats lack 247 base pairs that code for the amino acids that allow the sweet taste receptor to be produced. This means cats are missing the T1R2 gene that is responsible for detecting sweet tastes in humans.
Without the T1R2 gene, cats are unable to taste sweetness. Their taste receptors bind to different molecules that humans describe as umami or savory. So foods that taste sweet to humans produce no taste at all for cats, as they lack the proper receptor.
Cats Can’t Taste Sweetness Like Humans
Unlike humans, cats lack the sensory system to detect sweet tastes in the same way. Research has shown that cats do not possess the same sweet taste receptor genes (T1R2 and T1R3) that allow humans to perceive sugars as having a sweet taste [1]. These specialized taste receptor proteins bind with sweet molecules like sucrose and trigger nerve signals to the brain that we interpret as sweetness.
In a 2005 study, researchers examined the genome of domestic cats and found that the DNA sequences for the T1R2 sweet taste receptor were non-functional [2]. This means cats lack the biological machinery to transduce sweet carbohydrates into a sweet taste sensation. Without the T1R2 receptor, cats simply can’t register or perceive sugars as having a sweet taste in the way humans do.
So while cats may show preferences for sweet foods, they don’t actually taste the sweetness like we do. Instead, they must rely on other taste sensations and nutritional associations to drive their food preferences and appetites.
Why Cats Need the ‘Sweet’ Taste
Although cats cannot taste sweetness like humans do, they still have taste receptors for sweetness that serve an evolutionary purpose. Researchers hypothesize that the sweet taste in cats developed as a way to identify calorie-rich carbohydrates and aid in the digestion of starch and sugars (NPR).
Cats are obligate carnivores and get most of their energy from protein and fat. However, they still need small amounts of carbohydrates for energy. Their sweet taste receptors likely help guide them towards starch-containing plants, fruits, and the glycogen in their prey animals that can provide a carbohydrate source (NCBI).
Even though cats cannot perceive the sweet taste the same way humans do, having some ability to detect sweetness helps them meet their minimal carbohydrate needs in the wild. While not as essential for domestic cats fed commercial food, this evolutionary remnant still drives some of their flavor preferences.
How Cats Taste Sweetness
Even though cats lack the T1R2 sweet taste receptor gene found in humans and other omnivores, they have a different receptor that allows them to detect some sweet tastes [1]. Cats have a functional T1R3 taste receptor gene that combines with another taste receptor, T1R1, to enable them to taste amino acids like glycine and alanine as sweet [2].
The T1R1+T1R3 receptor complex in cats is structurally different than the T1R2+T1R3 complex in humans that detects sugars like sucrose as sweet. Instead, the cat sweet taste receptor binds to amino acids, which elicit a sweet taste sensation even though cats cannot detect the sweetness of sugars [3]. This allows cats to enjoy flavors like meat and dairy, which contain higher levels of amino acids, while ignoring sugary foods.
Cat Food Flavors
Many commercial cat foods are marketed using flavor labels that appeal to human tastes, like “roasted chicken” or “grilled salmon.” However, these labels do not necessarily indicate how the food actually tastes to cats.
According to Purina, some of their most popular “sweet”-flavored wet and dry cat foods include:
- Fancy Feast Grilled Tuna Feast in Savory Juices – With tender grilled tuna and tomatoes in a delicious broth, this food is marketed as having a “sweet, smoky flavor.”
- Fancy Feast Medleys in Sauce Pate – The chicken medley flavor contains chicken, carrots, peas and spinach in a sauce. The carrot and pea ingredients likely give it a mildly sweet taste.
- Fancy Feast Classic Pate Chicken Feast – This pate-style wet food highlights its “delicate, sweet flavor” on the packaging.
- Fancy Feast Broths with Chicken or Beef – These broths are labeled as having a “mouthwatering sweet taste” despite not containing any carbohydrate ingredients.
- Fancy Feast Gravy Lovers Ocean Whitefish & Tuna in Sautéed Seafood Flavored Gravy – The gravy in this food provides a “luscious, sweet flavor,” according to the product description.
While these flavors may taste sweet to humans, cats likely experience them differently due to their unique taste receptors. The flavors are designed to increase palatability and appeal to cats’ preferences.
Safety Concerns
While cats do not taste sweetness like humans, it’s important to avoid feeding cats sugary foods meant for human consumption. Sugary foods like candy, cake, cookies, and ice cream provide no nutritional value for cats and can lead to obesity, dental problems, and possibly diabetes if fed in excess.
Cats are obligate carnivores and require a meat-based diet high in protein and low in carbohydrates. Their digestive systems and metabolism are not adapted to properly process sugars and other carbs. Consuming too much sugar can upset a cat’s stomach, potentially causing vomiting or diarrhea.
Some human foods are especially dangerous for cats. Chocolate contains theobromine, which is toxic to cats. Xylitol, an artificial sweetener found in sugar-free gum and candies, can also be deadly if ingested. Even sugar-free foods sweetened with xylitol should always be kept away from cats.
While the occasional lick of ice cream or nibble of cookie likely won’t harm an otherwise healthy cat, owners should never intentionally feed sugary human foods. Sticking to a balanced commercial cat food formulated specifically for feline nutritional needs is the healthiest approach.
Cats naturally prefer meat flavors over sweet flavors. Offer treats made for cats, like freeze-dried meats, that satisfy their cravings for something tasty yet remain safe and appropriate for their species.
Other Tastes Cats Can Detect
While cats cannot taste sweetness like humans do, they are able to detect other tastes quite well. Cats have taste receptors for sour, bitter, salty, umami (savory), and possibly fat flavors [1]. Their sense of taste likely evolved to detect bitter flavors associated with toxic plants and spoiled foods, as well as savory tastes from meat.
Cats also have a strong sense of smell that contributes to their flavor experiences. Their combined senses of smell and taste help cats determine the palatability and safety of potential foods. Although cats cannot taste sweetness from sugars, they do enjoy the flavors added to cat treats and foods, such as fish, liver, and cheese.
Conclusion
In summary, while cats do have the ability to taste sweetness, they do not experience it in the same way that humans do. Cats lack the T1R2 taste receptor gene that allows humans to detect sugary tastes. However, they do possess a mutated version of the T1R3 receptor that enables them to perceive some sweet flavors. Although cats cannot taste carbohydrate-rich foods as sweet, they can still detect sweet amino acids like glycine. Cat food manufacturers add these amino acids to make dry food more appetizing to felines. While cats enjoy sweet flavors, pet owners should be careful about letting them consume sugar, as it can lead to obesity, diabetes, and dental issues. The unique makeup of cats’ taste receptors allows them to pick up on a range of flavors, but sweets will never hit their tongues in quite the same sugary way as humans.
