Size of excrements: The droppings of rats are at least 4 to 8 times larger than that of a mouse. Both rodents would leave their excrements near where they feed and hang around.

Connection to outdoors: Usually Mice would forgo what outside world has to offer once they find themselves inside a human dwelling. They love the refuge from predators. They will survive only on what’s available inside. They would behave in somewhat parasitical fashion. Rats, on the other hand, would not be content with the shelter offered by human dwelling. Rats must keep an almost daily access to the natural world, outside, even if there is a decent food source on the inside. To this end Rats would keep their access path as an evident display of their intrusion to human eye.

Scope of Disturbances : Presence of Mice is harder to detect compared with Rats because disturbances caused by mice are smaller in scope and can be overlooked during inspections by untrained eyes.
Rats can affect much larger objects and can dig out significant amount of dirt that makes one wonder if it was another animal altogether.

Gnawing Impact: Rats would cause serious damage to anything they put their teeth to. At times, rats can make a targeted article to be completely disintegrated so as to wonder if the object was in its place or not. The damage caused by mice can be overlooked in comparison.

Demeanor : While both rodents are typically nocturnal, Mice are more inconspicuous about their movements as if they are a good guests and don’t want to be refused hospitality. Rats, on the other hand, have no such cares. Rats behave the same way as if they were in the wild. That’s why a Rats’ presence is hard to miss.