Animals are widely divided into two categories knowingly-unknowingly, that is- prey or predator. For example, animals like rabbit and mouse have general tendency to escape and move quickly, hence they are born preys.
Considering the wild range and variety of cats that exist, it is considered that the cats are both prey, as well as predators depending upon the situations.
Animals tend to study body language and size at first sight. Small cats are cuddly in nature while small dogs are highly temperamental. On the other hand, big dogs are perfect combination of fierce, sweet and cuddly temperament.
There are cases where dogs are scared of cats too. Its still a big theory that is yet to be proven.
I hope this answer helps!😊