When we were young, we must have all watched the cartoon Tom and Jerry and knew that cats and mice have always been mortal enemies, and cats have the skill to catch mice. However, what I want to talk about today is not why cats like to catch mice, but why cats like to eat fish so much? It should be known that fish are aquatic animals, so why do terrestrial animals like cats uniquely prefer to eat fish?

It is well known that cats have a pair of bright, expressive big eyes, and many people adore them because of these eyes. These eyes are also an important reason why cats like to eat fish. Studies have found that cats are nocturnal animals and need a substance called taurine to improve their night vision. Cats themselves cannot produce enough taurine, but mice and fish are rich in this substance. Therefore, cats supplement their bodies' taurine needs by catching and eating mice and fish. If cats lack this substance for a long time, their night vision will gradually weaken until they can see nothing at night, almost like being blind. This also limits their ability to move around at night.

So, cats eat fish not only because they like it, but mainly because they need to supplement taurine by eating fish. There is also a legend that in the past, when people went fishing at sea, they would keep a few cats on the boat to catch mice. When there was not enough food to feed the cats, people would feed the cats the caught small fish. Fish are a delicious and nutritious food for cats, which they all especially like. Gradually, the habit of cats liking to eat fish was preserved and has been passed down to this day. Of course, this explanation is just speculation without scientific basis.

Also, not all cats are purely terrestrial animals; some cats can swim. Generally, not many domestic cats can swim, but their close relatives, leopard cats, can, and are considered swimming champions in the cat family. This suggests that cats’ liking for fish does have some basis. As long as cats keep eating fish, they can maintain their glowing eyes at night.