How could a cat fall in love with tuna when it lives inland?

The impression that "kittens love to eat fish" is deeply rooted in people's minds, and among all fish, cats seem to be particularly obsessed with tuna . Many cats are obsessed with the taste of canned tuna, and cat food is often equipped with tuna flavor as standard. Even veterinarians will recommend using a small piece of tuna meat or tuna juice to trick kittens into taking medicine obediently.

They flutter as soon as they open a can of tuna! ｜Viralhog/Youtube

Before becoming human masters, cats living on land rarely had the opportunity to eat fish , let alone large ocean-going fish such as tuna. How did something that their ancestors never ate become a favorite of modern kittens? A recent study found that the answer lies in the unique taste system of cats .

Cats’ sense of taste is very different from humans’

The taste system of domestic cats is very different from that of humans. During evolution, cats' sweet taste receptors lost their activity , so they can't perceive sweetness and love candy like humans. In addition, cats are less sensitive to bitter and salty tastes than humans .

Cats can't taste sweetness, but they may also be attracted to substances such as fat in desserts | Tuchong Creative

Why do cats have such a dull sense of taste compared to humans? Does this affect their eating habits? In fact, different eating habits naturally lead to different senses of taste.

Domestic cats are obligate carnivores , and whether their food is sweet, salty or bitter does not have as much impact on their survival as non-carnivores. Sweet carbohydrates and bitter toxic substances mostly appear in plants , and omnivores need to carefully distinguish them in order to consume more energy while avoiding danger. However, cats, who almost completely do not eat plants, do not have this worry.

Additionally, since meat naturally contains more sodium than fruits and vegetables, cats who eat a lot of meat are less likely to become deficient in sodium than non-carnivores , so they don't need to have a very sensitive salty taste.

Of course, being insensitive to sweet, salty, and bitter tastes doesn’t mean that cats are complete taste idiots— domestic cats have a sensitive and unique sense of umami, which is very important for their choice of meat food .

Tuna: Hitting the cat's taste buds

In fact, like sour, sweet, bitter and salty, umami is also an important basic taste . Generally speaking, the chemicals that stimulate this taste are free amino acids and nucleotides . Different animals have different taste receptors, so they prefer different umami tastes.

In a recently published study, researchers have for the first time analyzed in detail the umami receptors on cats' tongues and how they respond to different umami substances. Through computer simulations, cell experiments, and actual tasting tests, they discovered the unique nature of cats' umami perception that is different from that of humans.

MSG (monosodium glutamate) can make people feel a strong umami taste, but cats' tongues are not activated by this substance | Tuchong Creative

On the human tongue, the most critical component for stimulating umami is amino acids (such as glutamate, which is made into monosodium glutamate), and nucleotides (such as guanylate in mushrooms) play a supporting role in amplifying umami . However, in cats, the way to activate umami is just the opposite : nucleotides are the most important chemicals for activating receptors, and amino acids can only play a secondary auxiliary role.

Moreover, the experiment found that the combination of inosinic acid (a type of nucleotide) and histidine (a type of amino acid) is most favored by cats. If these two substances are added to water, the test cats will be addicted to drinking water, and the effect is better than adding other amino acids and nucleotides.

Tuna is also rich in inosinic acid and histidine, which may be the reason why cats like tuna . Whether it is other edible fish, such as red snapper, or livestock such as pigs, chickens, and cattle, the free histidine content in their meat is much lower than that of tuna. Therefore, in the eyes of cats, these meats may be less delicious than tuna.

Tuna just happens to contain the chemical that hits cats' taste buds the most | Tuchong Creative

Delicious but don’t drink too much

Some cats have a strong love for tuna and even develop a "tuna addiction" phenomenon - that is, they no longer want to eat anything other than tuna meat.

Although tuna is delicious, it is not suitable as a staple food for cats | pixabay

This picky eating behavior can be harmful to your cat's health . It's fine to give your cat tuna as an occasional snack, but neither fresh tuna nor canned tuna is a good staple for your cat. Eating only tuna for a long time can cause nutritional problems such as vitamin E deficiency and may also lead to excessive mercury intake. If your cat has become addicted to tuna, it's best to mix it with other foods and slowly reduce the amount of tuna you feed him.

Of course, tuna-flavored cat food is nutritionally balanced , so it will not cause "tuna addiction" problems. In fact, the researchers also hope that their findings can help develop a "tuna flavor" that cats are more addicted to, so as to improve the taste of cat food and cat medicine .

References

[1] https://www.livescience.com/animals/domestic-cats/scientists-finally-figure-out-why-cats-are-obsessed-with-tuna

[2] https://www.science.org/content/article/why-do-cats-love-tuna-so-much-scientists-may-finally-know

[3] https://academic.oup.com/chemse/article/doi/10.1093/chemse/bjad026/7238703

Author: Window Knocking Rain

Editor: Bowl

Title image source: Tuchong Creative