Rats and most rodents have similar body structure as they belong to the same family. Rat is the most devastating one among them. So in true sense of term, only rats can be called as pest. Rats are long tailed animals ranging from small to medium size. These animals were initially found in Africa and Asia. They migrated worldwide on ships sailing for trade to different ports of the world. These rats are now present in every country in the world and doing their part in devastating human society. Many rodents are mistaken as rats since they look similar to rats. Mouse is smaller than rats but they are equally harmful. Other rodents do not cause as much harm as rats and mice do. There is no such place in the world where these rats and mice are not found. The rat found in houses is known as brown rat. These are the most commonly found rat in this world. This rat is also the most harmful rat in entire rat family. These rats travelled to every part of the world in couple of centuries.

These house rats like warm climates to live. The love to live in or near human habitat. They are night creatures. They come out of their holes during night hours only. But some of them are visible in both day and night to hunt and eat. They live in big groups. These groups are called packs. When a young pair of rats separate from their pack, they form a new pack in a new location. Their migration gives them new place to live and new resources of food. Rats eat anything. They can eat everything. But they are carnivorous by choice. They like yo eat meat. Rats are solely dependent on humans for their food resources supply. They love to eat human food. They eat the left over and scavenge through trash and garbage.

Rats eat grains. They prefer to scavenge through agricultural fields. They live in food grain warehouses and eat away. As per national estimate, 35 to 40 percent of reserve food grain stocks are destroyed by rats every year. Rats eat insects, living or dead. They eat small creatures like snails, small birds, mammals or reptiles for food. Rats eat fruits and seeds. In fact, there is nothing left by rats to be eaten and they harm humans mainly by destroying their food supply. Rats reproduce at an amazing speed. A brown rat or a house rat can produce up to 2000 offspring in a year. An average rat life span is two to three years. So, a rat produces about 6000 offspring before it dies. Rats are a major threat to human society. They harm human health in a profound manner. They transmit a number of serious diseases. Many of them fatal. Many of them in form of epidemics claiming million lives. The rats cause serious damage to human properties. They eat through furniture, garments, books, papers and everything eatable in the house.

The rats eat human food, but they spoil the rest by dropping their hairs and excrete on them. They consume more than three times more than the world human population in a year. They spread epidemics to kill humans.

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Hazards spread by house rats

House rats are putting human society to harm by mainly three ways.

By destroying food resources
Rats are the biggest destroyers of human food resource. They eat everything human eats. Rats dwell in agriculture fields. They eat grains before and during they ripen. They damage food grains right from agriculture sites. The rats also live in packs in food grains ware houses. They consume more than three times of world populations of humans in a year. Humans produce 400 per cent of their food requirements and still starve. More than 70 percent of world population suffers from malnutrition because of the rats. The rate at these rats reproduce, humans will die without food one day. The day is not far. Rats spoil food which they do not eat. They leave their hairs and excreta on the food. The food becomes poisonous, contaminated and unfit for human consumption. This is also a major destruction of human food.

By spreading deadly diseases
Rats are the only carriers of the deadly disease Plague. The fleas which carry plague virus ride on the rats. Rats live in human houses and thus rats help fleas to spread plague in humans. Plague is a deadly disease. The infected person suffers very badly from fever, cough and cold. They infected person later develops nodes in lymph glands. These nodes are called bubones and thus this plague is called bubonic plague. This plague is fatal and is hard to cure. Almost entire England was wiped out by this plague in Couple of centuries back. Rats are also carrier of Rabies virus. A person may develop rabies if bitten or scratched by an infected rat. The disease is commonly known as Hydrophobia. The infected person cannot drink water in this disease and ultimately dies. Rats spread diseases of gastro intestinal tract in humans. The humans become infected after eating rat contaminated food, and suffer very much. Rats also spread tuberculosis in humans. They are a potent carrier of tuberculosis bacteria and they contaminate the human houses with the bacteria. People with weak body resistance become easy prey to tuberculosis which is again a hard to cure disease.

By destroying human property
Since rats live in human houses, they eat and destroy everything in the house. Rats destroy furniture, garments, books, soft materials, and every such thing it can chew and eat. What they cannot eat, they chew and destroy.