Rats (commonly known as rats) are mammals, rodents and rodents. Its main characteristics are that the body is conical, without canine teeth, there is a gap between the front teeth and premolars or molars, the front teeth are developed, without roots, they grow for life, and ordinary teeth are short; Act quickly; Plants are staple food, and some are omnivorous; There are many kinds. The mouse is a kind of rodent, and its size is large and small. There are many kinds of mice, there are more than 450 kinds in the world. Mouse is one of the most primitive mammals in existence. They are energetic, numerous, extremely fast in reproduction and adaptable. They can eat almost anything and live anywhere. Rats can dig holes, climb trees and spread diseases such as plague, epidemic hemorrhagic fever and leptospirosis. However, mice provide countless experimental data of drugs.