Much has been said and written about the sixth sense of dogs and cats (and all Animals as a whole). Although many have behaviors that surprise us, and sometimes frighten us, for example, dogs barking in the dark or cats that bristle seemingly without reason, it is not scientifically proven that they have a sixth sense.
It may, however, be "deduced" that many of these assumptions about a sixth sense are related to the more developed senses that dogs and cats have in relation to us. With a better auditory, olfactory and visual capacity, the world around us can change radically as well as the way we interact with it.
This is exactly what happens with dogs and cats, their senses allow them to develop relationships with the environment that are impossible for us because we do not have the tools needed to access that kind of reality.