RAT Rattrus norvegicus/Rattus rattus

The roof rat and the brown rat have lived with people for so long that some scientists think of them as domesticated (or friendly). Scientists like to remind us that rats are talked about in the Old Testament of the Bible. Even though rats live with people, they keep total control over their own lives. Rats know how to live among people and not become dependent on people for survival. Although the roof rat and the brown rat can live in the wild and in high mountains in California, places where there are lots of people have become their favorite environment.

Wherever people go, rats follow. The rats were the first animals listed by a scientist who studied nature named Linnaeus. Linnaeus named the brown rat rattus norvegicus because of Sweden's northern neighbor, Norway. These neighbors had dirty sewers, dirty kitchens and basements for hundreds of years.

The roof rat, or the black rat, was brought to Europe from Israel by the Crusaders. The rats had fleas, which carried the Black Plague. The Black Plague was a disease that killed one third of the people in Europe. The roof rat can be light gray or black, with large, black eyes, big, soft ears and soft fur.

The brown rat is much larger that the roof rat. It can grow up to 16 inches, including the tail. It has fur that is not as soft as the roof rat. Of the two, the brown has the worst reputation. This is the rat that people see in garbage cans, and granaries. The brown rat is the most hated rat, and next to people, it is an animal that does the most damage in nature. It is funny to think that the laboratory rat, which is a domesticated brown rat, is the most helpful animal for people who study medicine. The brown rat and the roof rat can live in the same city, but they live in their own habitat or niche. The roof rat likes to live above the ground and it eats mostly vegetables, fruits, nuts and berries. It travels by running along telephone wires, on the tops of fences, and on tree branches. It lives in woodpiles and in the branches of thick bushes.

The brown rat lives on the ground. You can find brown rats in factories, docks and places that are covered with ivy. The brown rat likes to dig tunnels. It is a true omnivore. It will eat anything that will not bite back.

A professor at Cal State Dominguez Hill named Tony Recht, put radio collars on brown and roof rats. He found out that the roof rats did most of their work at night. The brown rats were busy during the day and at night, as long as there were not many people around.

Both types of rats do not like people to get to close to them. To escape, the brown rat can run very fast. They also learned stay away from the areas where they were caught and fitted for radio collars.

The color and body size of the rat help it to survive among people. Their color helps them blend into the shadows. Their small size helps them hide in the cracks and holes of buildings in the city. Rats also survive by having lots of babies. Most brown rats live only for one year. But they have four or five litters of four to ten ratlets or babies per year. The roof rat does not have as many ratlets. It only has five litters of five ratlets per year.

Rats are uninvited guests but it is hard to get rid of them. Art Tilzer, director of the Bureau of Health, says that people complain less of rats these days. This could mean that there are fewer rats or that people have learned to live with them.