Alex Lawrence, age 7, of Pascagoula, Miss., for his question:

IS A RAT JUST A LARGE MOUSE?

A rat is not just a large mouse. It is a furry animal that looks like a mouse but it is much bigger. The smallest kind of rats grow longer and weigh more than the largest mice.

Rats, like mice, beavers and squirrels, are rodents. All such animals have chisel like front teeth especially suited for gnawing.

There are about 120 kinds of rats in the world. Best known are the black rat And the brown rat. Most of the other kinds live in areas not inhabited by people.

Black rats and brown rats rank among the most serious animal threats to people. They carry the germs of several diseases and also destroy or damage crops and other food products. Rats also kill poultry, lambs and baby pigs.

Black and brown rats grow to be between eight and 10 inches in length.