A domestic cat’s sense of taste is not quite as good as ours which is reassuring because in many respects the domestic cat’s senses are superior to ours. However, as you might know, they have difficulty in tasting sweetness.
Like us, the domestic cat responds to 4 basic tastes:
- sour
- bitter
- salt
- and sweet.
To all for tastes, humans respond strongly. But cats are weak when it comes to one of these tastes: sweetness. Domestic cats lack a sweet taste receptor as explained in the technical section below.
Technical reason why domestic cats lack sensitivity to sweetness
Research has taken place on the molecular basis of cats’ inability to detect sweetness in food. A study identified and sequenced the two genes (Tas1r2 and Tas1r3) involved in sweet perception in cats, as well as in other members of the Felidae family. The results show that while the cat Tas1r3 gene is functional and expressed in taste buds, the cat Tas1r2 gene is a non-functional pseudogene due to a 247-base pair microdeletion in exon 3 and stop codons in exons 4 and 6. This deletion is also present in the Tas1r2 genes of tiger and cheetah. Therefore, the cat lacks a receptor necessary for detecting sweet stimuli, and this molecular change likely played an important role in the evolution of the cat’s carnivorous behavior. Link to this project: https://doi.org/10.1093/jn/136.7.1932S
My thanks to Chat GPT.
Historical reference
Until around the late 1980s, some experts believed that the cat showed no response at all to sweet tastes. That was the traditional wisdom but as you can see in the research above and in other research studies, we now know better.
In one study they diluted milk (which cats love because it is fatty) to a quarter of its normal strength and divided that liquid up into two containers. They sweetened one and not the other. The cat chose the sweetened milk. This confirms that they can taste the sweetness and prefer the taste when the taste of milk is heavily diluted.
The upshot being that cats can prefer sweetness under certain conditions but normally would much favour the taste of fat.
Dr. Desmond Morris in his book Catlore states that domestic cats detect the above four tastes in the following order of sensitivity:
- Sour
- bitter
- salt
- sweet
The domestic cat’s tongue
I guess you know that the surface of middle area of the tongue is covered with papillae (spiny protrusions) which are used to rasp food from bone when eating prey and to effectively groom themselves and stimulate their sebaceous glands in their skin. In the area where there are the papillae there are no taste buds.
The taste buds are confined to the tip, the sides and the back of the tongue only. Sour tastes can be detected in all these areas, but bitter is confined to the back part and salt to the front.
Sense of smell
Interestingly, the domestic cat decides on the palatability of its food not from taste but from smell. And you will see this quite obviously when the first thing that a cat does when they eat is to smell the food. And they might reject it there and then. A cat’s sense of smell is much better than ours and they can decide with great conviction whether they want to eat the food put before them or not based upon its scent.
Temperature
The temperature of the food can be important too. Cat caregivers will probably have found this out. For example, I treat my cat with cooked king prawns from the fridge. When they are taken from the fridge, they are obviously cold. I break them open so they smell more and I also give them about five seconds in the microwave sometimes. He prefers them when they been microwaved very gently because they smell more.
The innate characteristics of the domestic cat’s wild ancestor are still a major part of the domestic cat’s characteristics and as the wildcat eats freshly killed prey at around 80°F, the domestic cat likes food at that temperature as well. It happens to be the same temperature as the cat’s tongue.
If your cat is being picky, I would strongly suggest that you heat the food in the microwave but with great caution and only for about five seconds just to add a little bit of heat to it. It will make it much more attractive your cat. Check its temperature before serving it up. You don’t want to harm your cat.
2 different types of backward facing papillae on the domestic cat’s tongue
