The Rodent word has been derived from Greek word “Roder” which means to gnaw i.e. animals belonging to Rodent have gnawing habit. Rodents includes mostly rats, squirrels, porcupine etc. Rodents belongs to Phylum-Vertebrate, Class-Mammalia Order-Rodentia and among these rats belong to family Muridae. Its order Rodentia includes a great number of animals ranging in size from the smallest mice to as large as porcupine. Rodents are easily distinguished from other mammals by the characteristics arrangement and form of their teeth.

The rodents commonly known as rat, is amajor enemy of mankind. It is essentially a pest of food and fodder. Rats comprise a major group of pests, which are of great economic importance due to their destructive role in problems of food, health of man and daily use articles.

The habit, nature, behavior and ecological adaptation of rodents have become major factors for their wide distribution and enormous population. Literature shows that the war against rodents started as early 5000 years ago with the advent of Agriculture. Since 1975 they have been identified as a “National Pest” and enemy number one of mankind in our country.

Rats are the most notorious pests of different commodities in the fields as well as when these commodities are stored. A number of crops like vegetables, oilseeds, cereals etc., at early stage in field, are eaten and contaminated by rats. They are also seen playing a vital role in transmission of public health diseases viz., plague, leptospirosis etc. to humans and other animals.
Some common species of rats in India:
Basis of their shelter, rats can broadly be divided into two groups.

House rats Field rats Found in both field as well as houses Rattus rattus(House rat) Bandicota bengalensis (Lesser bandicoot) Rattus norvegicus(Norway rat) Mus musculus (House mouse) Tetera indica (Indian gerbil) Rattus rattus rufescens (Indian Black rat)   Nesokia indica (Short tail mole rat) Bandicota indica (Large bandicoots)   Rattus meltada (Soft fur field rat)     Mus booduga (Field mouse)     Meriones hurrianae(Indian desert gerbil)     Golunda ellioti(Indian Bush rat)  

Rats are very clever & suspicious animal by nature and have distant reaction to the new objects called Neophobia. Water is essentially required daily by the rodents, but mouse can survive without water for many days. Rats can survive without food up to a week but it cannot survive without water continuously for more than 3 days. They not only feel shy of the baits but become worry as and when a single member of their family dies.

Their feeding times are normally confined to dusk and down.Rodents not only feed on grains but also contaminate 20 times more than what they consume with their feces, urine, hair and even some times with their own dead bodies. On an average each rat drop 25 to 150 pellets voids 15 to 25 ml urine and shed thousands of body hairs / fur daily. Gunny bags are torn by rats which leads to spoilage of foodgrains. Rats are known to eat the grains partly and also to eat its embryo point making it unfit as seed leading to waste. The rodents damage the foundations of the building and other articles of daily use. Besides they transmit at least 35 types of communicable diseases to man.

The estimate of foodgrains losses by rodents in India range from 2.4 million tons to 26 million tons per year. According to an estimate 6 rats eat one man’s food daily and there are ~2400 million rats in India. According to Panse’s report about 2.5% losses are caused due to rodents in storage. The rodents on an average consume food grains about 8 to 15% of their body weight daily.