I wonder if the fear is not connected to disease.'' Perhaps a more logical reason is that rats appeal to our baser instincts a fear of things that go bump in the night. They're nocturnal creatures,'' Linkey says. Most rats, of course, don't live in captivity. Of the nearly 120 kinds of rats, the best known are the black rat and the brown rat. The latter is most common throughout the United States.
Brown rats tend to live under floors, within walls, in piles of garbage or in the ground.
Like other types of rats, they have a keen sense of smell and can sense danger very quickly. They tend to be more aggressive than their black cousins. Rats tend to live in large groups that have dominant individuals. They feed mainly at night and sometimes band together to attack larger animals such as chickens and piglets. Interestingly enough, brown and black rats originally lived only in Asia.