The reason why cats like to sleep in the sink is because their ancestors lived in the wild and they like to sleep in small gaps. This habit is still retained after being domesticated. Wash basins are usually small, which is in line with cats' preference for small places and provides a sense of security.

In addition, this is why cats like to hide in boxes and other places where they can hide themselves. Scientific methods have proven that these places can Reduce their stress levels. Following this line of thinking, it’s obvious why cats love sinks.