Introduction
Cats have a sense of taste that is quite different from humans. Their taste buds and receptors are structured differently, allowing them to taste certain flavors while being insensitive to others. While humans can perceive all 5 main taste groups (sweet, sour, salty, bitter, umami), cats lack some of these abilities. Their sense of taste has evolved based on their carnivorous diet and reliance on smell to detect food. Understanding how cats experience different flavors provides insight into their preferences and aversion for certain foods.
Anatomy of the Feline Tongue
The feline tongue has a unique structure that allows cats to groom themselves and lap up liquids efficiently. It contains small, backward-facing spines called papillae that give the tongue its rough, sandpaper-like texture.
In addition to the spiny papillae, a cat’s tongue contains thousands of tiny projections called filiform papillae which do not have taste buds but help the cat lap liquids and ingest food. Taste buds are concentrated on the sides at the back of the tongue, with fewer at the tip. Cats have around 470 taste buds compared to a human’s 9,000. https://www.hillspet.com/cat-care/behavior-appearance/cat-tongues-explained
The dense network of intertwined muscles gives a cat’s tongue both coarseness to groom fur and flexibility to lap up water. The papillae act like a tiny scoop to draw liquid up in a column from the surface directly into the throat with precision. https://www.wellpets.com/blog/111-all-about-your-cat-s-tongue
The Feline Sense of Taste
Cats have a significantly weaker sense of taste compared to humans. While humans have around 9,000 taste buds, cats only have around 470 taste buds (Purina, 2023). This means cats experience flavors differently than humans.
Cats have taste receptors that allow them to detect sweet, sour, bitter, salty, and umami tastes. However, their experience of sweet flavors is limited. Cats lack the amino acid transporters that allow humans to fully taste sweetness (Spruce Pets, 2022). While cats can detect some level of sweetness, they do not experience the full sweet taste that humans do.
While not as sensitive to sweet tastes, cats have a strong sense of bitter flavors. Their taste buds easily detect bitter compounds, allowing cats to avoid toxic plants and spoiled foods that contain bitter components (Purina, 2023). Cats also have a heightened sensitivity to sour and salty tastes compared to humans.
The feline sense of taste plays an important role in providing cats with information about the foods they eat. However, compared to humans, cats have a much weaker overall sense of taste and do not fully experience certain flavors like sweetness.
Flavors Cats Can Taste
Although cats have fewer taste buds than humans, research shows they can perceive four out of the five primary taste groups that humans can. Cats have taste receptors for savory, sweet, bitter, and sour flavors.
Cats enjoy savory flavors, also known as umami. Umami receptors detect glutamates which are found in meat and fish. This explains why most cats love foods like tuna and salmon. According to research from PLOS One, cats have a high preference for savory flavors which likely evolved to help them seek out protein-rich foods [1].
While not as sensitive as humans, cats can identify sweet tastes. They have functional sweet taste receptors and will show preference for sugary foods like ice cream [2]. However, their sensitivity seems to vary between individuals.
Cats also detect bitter tastes which likely helps them avoid toxic plants and spoiled foods. Bitter receptors send strong avoidance signals to the brain.
Lastly, cats can identify sour flavors such as citrus fruits or vinegar, though their tolerance varies individually. Sour taste sensitivity may help cats avoid unripe foods.
Flavors Cats Cannot Taste
One of the most notable differences between feline and human taste is that cats are unable to detect sweetness. Cats lack 247 base pairs on the Tas1r2 gene which contains the genetic code for the sweet taste receptor (https://www.thesprucepets.com/which-tastes-cant-cats-experience-5072674). This means cats do not possess functional sweet taste receptors on their tongues. While humans experience taste through taste buds grouped together in structures called papillae, cats’ papillae contain very few taste buds overall. Additionally, cats’ taste buds are located primarily at the back of the tongue, while humans have taste buds covering almost the entire tongue (https://www.hillspet.com/cat-care/nutrition-feeding/cat-food-taste-and-types).
Because cats cannot detect sugary or sweet flavors, they respond differently than humans to flavors like chocolate or sweet fruits. Cats are generally indifferent to sweet foods. This is why cats may ignore sugary treats or show interest in salty and sour human foods over sweets.
The Science Behind Feline Taste
Cats lack the amino acid and gene coded for the sweet taste receptor T1R2 in their DNA, specifically the Tas1r2 gene is absent which encodes the taste receptor protein to detect sweetness (Li et al., 2006). This prevents cats from being able to detect or taste anything sweet, unlike most mammals including humans who possess this gene and can register sweet flavors.
According to a 2005 study by Li et al. published in PLoS Genetics, researchers examined the genome of domestic cats as well as big cats like tigers and lions. They discovered cats are missing 247 base pairs on chromosome 6 where the Tas1r2 gene is located in most mammals. Without this gene, cats do not have the biological machinery to produce the sweet taste receptor T1R2 protein. This affects their ability to taste anything sweet (Li et al., 2006).
While cats may still respond to high concentrations of sugars, they cannot detect the sweet quality the way humans can. Scientists confirmed this by observing a lack of neural response in the cat brain to various sweet solutions. Cats also show indifference to artificial sweeteners which would taste very sweet to humans (NPR, 2005).
Evolutionary Adaptations
Cats have evolved without sweet taste receptors for an important evolutionary reason – survival. As strict carnivores, cats have no biological need to detect sugars or carbohydrates in their diet, which come mainly from plants. In the wild, cats thrive on a high-protein diet consisting almost entirely of meat. So the ability to taste sweetness offered no evolutionary advantage for feline survival.
Researchers believe that cats lost the ability to taste sweet foods over time, as they became more adapted to hunting and eating prey. Their tongues optimized instead for detecting amino acids from protein sources. This gave cats an edge in tracking down nutritious food sources packed with the meaty protein they need.
According to recent research, cats have only 473 functional taste genes compared to about 900 in humans. Their reduced taste receptor range allows cats to focus in on flavors critical to their carnivorous needs – namely, the savory umami taste that detects protein-rich foods.
Impacts on Diet
A cat’s inability to taste sweetness has a significant impact on its dietary preferences and needs. Since cats lack sweet taste receptors, they are generally uninterested in and may be averse to foods that humans perceive as sweet (Cats Protection Blog, 2018). Foods with high sugar content tend to be unappealing to cats.
This physiological constraint helps explain why cats have evolved to prefer meat-based diets. As obligate carnivores, cats require certain nutrients like protein and taurine that are found in animal flesh, not plants. Their lack of interest in sugary or starchy foods reflects their bodies’ nutritional requirements (Li et al., 2006).
When developing commercial cat food products, manufacturers take into account that cats cannot taste sweet flavors. Cat food tends to rely on meaty flavors and aromas rather than sweeteners to appeal to feline preferences and appetites. Understanding the cat’s unique sense of taste helps ensure they are provided with a palatable, nutritionally appropriate diet.
Other Senses Cats Rely On
While cats have a weaker sense of taste compared to humans, they rely more heavily on other senses to assess their food, with smell being the most important.
Cats have a highly developed sense of smell, with around 200 million odor-sensitive cells in their noses, far exceeding the 5 million found in humans. Their sense of smell is 14 times stronger than humans, allowing them to detect pheromones and locate prey. Cats use smell to identify food, relying on aroma rather than flavor.
Cats also rely on the texture or “mouthfeel” of their food. Their tongues have tiny barbs or hooks called filiform papillae that help them lap and grip food. Cats prefer foods with a smooth, tender, juicy texture. Dry, tough foods are unappealing.
In addition, cats have excellent vision compared to humans. Their eyes have a wider field of view, night vision capabilities, and can see light frequencies invisible to humans. Cats rely partly on visual cues like shape and color when assessing food.
Conclusion
In summary, domestic cats have a limited sense of taste compared to humans due to having far fewer taste buds. Cats can primarily detect salty, sour, bitter, and umami flavors but lack the ability to taste sweet flavors. This is because they lack a key receptor gene that allows mammals to detect sweetness. From an evolutionary standpoint, not tasting sweet flavors benefited feline ancestors as strict carnivores. Today, though, it impacts the diet and food preferences of domestic cats, who must rely more on their strong sense of smell and other senses when evaluating food. Understanding the cat’s limited taste abilities provides cat owners insights on creating appealing food and treats. The feline sense of taste, while more restricted than a human’s, is still an important factor in their overall sensory experience of the world.