Why Do Cats Love Tuna? Umami Taste Receptors in Felines Explained

Besides Garfield's iconic affection for lasagna, few foods are as synonymous with cats as tuna. Despite its unusual appeal for desert-evolved animals, tuna is a staple in cat food, accounting for over 6% of wild-caught fish used. Now, researchers have found a scientific explanation for cats' love for this fish.

Cats Have Receptor Genes to Detect Umami

A recent study, titled "Umami Taste Perception and Preferences of the Domestic Cat (Felis catus), an Obligate Carnivore" published in Chemical Senses has uncovered that cats possess taste receptors enabling them to detect umami, the savory flavor present in various meats, constituting one of the five basic tastes alongside sweet, sour, salty, and bitter.

This revelation underscores that umami appears to be the primary flavor sought by cats, aligning with their obligate carnivore status. What makes this finding particularly intriguing is that these cat umami receptors are finely tuned to molecules found at high concentrations in tuna, offering an explanation for cats' strong preference for this particular seafood delicacy.

Yasuka Toda, a molecular biologist at Meiji University renowned for her work on the evolution of umami taste in mammals and birds, lauds this study as significant in understanding our feline companions' taste preferences.

She suggests that its findings could potentially assist pet food companies in developing healthier diets and more appealing medications tailored to cats, emphasizing the potential practical applications of this research in the pet industry.

Cats exhibit a unique palate characterized by their inability to taste sugar due to the absence of a crucial sugar-sensing protein, which is likely a reflection of their meat-based dietary choices devoid of sugar. Additionally, cats possess fewer bitter taste receptors than humans, a trait commonly observed in strict carnivores.

Nonetheless, the study's focus centered on their capacity to perceive the savory essence of meat, specifically umami. Through a genetic analysis of a 6-year-old male cat's tongue, the researchers unveiled that cats indeed express both Tas1r1 and Tas1r3 genes in their taste buds, fundamental components required to detect umami.

This marks a groundbreaking discovery, as it provides the first concrete evidence of cats possessing all the molecular components essential for umami perception, shedding light on the evolution of feline taste preferences.

Umami Is to Cats as Sweets Are to Humans

While there are some resemblances between the receptor genes in cats and humans, the research team uncovered a significant difference in how these receptors operate. Amino acids and nucleotides collaborate to initiate the response.

In humans, amino acids bind to the receptors first, followed by nucleotides. However, in cats, the sequence is reversed: nucleotides activate the receptors first, with amino acids following.

Scott McGrane, the lead author and a flavor scientist at the Waltham Petcare Science Institute, described this reversal as the "exact opposite of what we see in people." Toda compared the importance of umami for cats to that of sweetness for humans. She noted that dogs can taste both sweetness and umami, potentially explaining their less selective eating habits.

The study found that it was not just umami in general that cats craved; they exhibited a distinct preference for bowls containing histidine and inosine monophosphate (IMP), compounds present in high concentrations in tuna. McGrane emphasized that this specific combination seemed to hit the umami sweet spot preferred by cats, shedding light on why cats are so fond of tuna.