World Facts

How Many Rats Are There In The World?

It is impossible to quantify the rat population of the world, however their numbers are estimated to be in the billions.

Believed to be the most populous mammal, rats are found in almost all continents. Billions of them are on the planet with China believed to have more than two billion rats. A rat is a four-legged mammal of the Animalia kingdom characterized by a long tail and a furry body. There are more than 64 types of rats with an average size of between 9 and 12 inches long excluding the tail though some species can grow to over 30 inches. Although they do not see far, their nose and ears have well-developed senses. A rat has different names depending on its age. At birth, rats are known as kittens whereas a pregnant rat is called dam. Buck refers to a male while a female is called a doe. Rats are social animals with value for the family system.

How Are Rats Counted?

It is scientifically impossible to quantify rats. This is due to their nocturnal and hibernating behavior. The attempt to use questionnaires has not yielded exact results. In the 1950s, people could count them in sewers and dumpsites. Various renowned institutions like the WWF and FAO have participated in the count. In China, when the water levels of Dongting Lake rose, millions of rats were flushed making it difficult to count. Rodent experts, like Professor Rob Smith of Huddersfield University, can give only an estimate. Bobby Corrigan, a rodentologist from America ranked Philadelphia, New York, and Boston as the highest rat infested cities. This is due to the dense population since the increase in human population is directly proportional to increase in rat growth in urban centers. London city has an estimated seven million rats.

What Leads to Such High Population of Rats?

A rat matures sexually between the ages of 4 and 5 weeks from birth and takes only 21 to 23 days to bring forth offspring. An average female can give birth to 6 to 8 pups. Thus, in one year it can give birth 6 times. This means that a single female can bring forth over 50 rats per annum. The mortality rate is very low because they live in groups to protect the young ones.

Rats are highly adaptive to different conditions and can live anywhere; on the surface of the earth, holes, up trees, or inside human houses. They are highly resistant to diseases. They are highly nocturnal, a quality that makes them evade human beings who are their greatest threats. Their perfect sense of hearing and smell makes them sense danger or food. In Northwestern India rats are domesticated, well taken care of, and even worshipped in temples making the rat population grow.

What Hampers the Population of Rats?

There would be even more rats if human activities did not interfere with the natural ecosystem that supported their breeding. In some continents, they are eaten while in others they are seen as a nuisance or disease carrier leading to them being eliminated. In Aleutian Island, deliberate efforts were made to get rid of rats which were very many making the place referred to as the Rat Island. In laboratories, they are used for research, further limiting their increase.

More in World Facts