What are the different species of rats ?

The rat is a very versatile and tough animal. It has a phenomenal capacity to survive in the most difficult situations. It was noticed that after nuclear tests, the rats in the area seemed the fittest and healthiest.

Rats are larger than mice and usually have scaly, naked tails. There are several species of rats.

The brown rat is about 20 cm. with a tail of almost equal length. These rats originated in Central Asia. Now they have spread throughout the world. Thanks to ships which transported them to all corners of the world.

The black rat, responsible for plagues, is smaller than brown rat. It has, however, larger ears, a longer nose and a pointed snout. They do not interbreed with brown rats.
The pack rat or wood rat is common throughout North America. There are about 7 different species of this kind. Their dens are made of partly eaten plants, dung and miscellaneous objects.
Rats have a very flexible body and can squeeze in through tiny holes, climb vertical surfaces, burrow the earth, jump as high as 1 metre and jump down from a height of 15 metre. They can swim at least a mile and can chew through live electrical cables. They can kill another animal which is twice their size. Rats seem to be very intelligent. They are awfully cautious, wary and shrewd.

Rats are supposed to have killed more than 25 million people - a quarter of the population of Europe - during the infamous Black Death. In 1348 rats travelling in ships from Black Sea to Genoa brought the plague bacterium on fleas that lived on its hair. The Plague lasted for more than 3 years resulting in a horror that changed the history of the world. Rats still are responsible for spreading diseases like typlus, trichinosis, Lassa fever and Salmonella.

Great damage is done to property by rats as they gnow through them. Rats pillage tons of food grains stored in the granaries. They devour potatoes, bananas, carrots and other produce in the fields. It is very difficult to eradicate the rat menace as they multiply very quickly. A female rat can reproduce and have at least 15,000 descendants in a year!

It seems rats have only one useful quality in them that is of value to man. They are excellent animals for the research laboratory where new drugs can be tested on them. Rats being tough, versatile, quick reproducers and having ability to eat 'anything' are the favourite animals for experimentation.