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Last updated date: 09th Apr 2024
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Is a Rat one of Those Pests?

Rat is one of the most common pests  around the world. Let's know about various types of rats, their classifications, characteristics and how they help to balance the ecosystem?

Rats or Rodents originated in Australia and Asia. They are medium- size, thin- tailed rodents that are now found all over the world. Members of the genus Rattus are "True Rats". Other rodents also share the same characteristics and are also referred to as rats. Rats are different from mice as they are larger with longer and thinner bodies. The most common rats in the world are the Brown and the house rats. Typical warmer climates are liked by bye and brown rats generally live in temperate climates. Rats can live anywhere like humans live. Many  species of rats also prefer trees to live in.

Other rat genera included in the order Rodentia are Neotoma (packrats), Bandicoot (bandicoot rats), and Dipodomys (kangaroo rats). Rats are differentiated with mice depending on their size. Generally, people also call rats as mice if the size of the rat is small. Rat term is used indiscriminately to several rodent families, who have a longer body than 12mm or five-inch. Scientifically, the term ‘Rat’ can be applied to any of 56 thin tailed, medium-sized rodents in the genus Rattus.


Rats originate from Norway rats. They were found in the streets of cities in the field of rural areas.  Norway rats were domesticated during victoria times and people started to breed them for attractive fur and colour. Rats are associated with humans for a long time, not always for good reason. In the world, some of them consider the rat as a bad sign and some consider it as a God such as in India.


Classification of a Rat:

The scientific classification of rat is as follows -

  • Kingdom -  Animalia 

  • Phylum - Chordata 

  • Class -  Mammalia 

  • Order - Rodentia 

  • Genus - Rattus norvegicus ( Brown rat), Oryzomys palustris ( Marsh rice rat), Neotoma cinerea (Wood rat), Rattus rattus( Black rat).

After going through the above classification of rats, It would be very easy to answer the questions like what is the scientific name of rat? The scientific name of rat is Rattus and on further classification, the scientific name for the black rat is Rattus rattus and the scientific name of black rat is Rattus rattus.


Types of Rats: 

Now let us see different types of rats given below -

1. Norway Rats

  • Norway rat is also known as Brown rat and they are 40 cm in length with a tail shorter than the head and body.

  • They weigh around 350 - 500 grams and have a blunt nose, small ears, and a thicker body when compared to the Black rat.

  • The gestation period of brown rats is about three weeks and it takes ten to twelve weeks from birth to sexual maturity. 

  • Brown rats are usually ground living and burrowing but sometimes they even climb.

  • Their preferred food is cereals and they eat around 30 grams of food a day and drink 60 ml of water

  • Brown rats or sewer rats sometimes called Norway rats, can be identified by their gray brown bodies. Tails Of these rats are shorter and their eyes and ears are small relative to the body.

2. Ship Rats 

  • Ship rats are also known as the black rat or roof rat and their length ranges from 16 to 24 cm, with a tail longer than head and body.

  • They weigh around 150 - 200 grams. They have pointed noses, large ears and slender bodies when compared to brown rats. 

  • The gestation period of black rats is about three weeks and they take 12 - 16 weeks from birth to maturity.

  • They often climb, agile, and rarely burrow. Black rats or roof rats are excellent climbers that build nests above the ground

  • Their preferred food is moist food and they eat around 15 gram of food per day and drink 15ml.

3. Woodrats 

  • Woodrats are also known as pack rats and they are found in the rodent genus Neotoma.

  • Packrats weigh around 250 - 600 grams. Packrats are relatively large because they occupy a large geographical area and its body size is correlated with the climate.

  • The length of wood rats ranges from 27 to 47 cm.

  • Packrats live in any place from low, hot, dry deserts to cold and rocky slopes in timber lines by building their nest.

  • Packrats are nest builders; they usually use plant materials like branches, twigs, sticks and other available debris to build their nest.

  • Woodrats are known to transmit Arenaviruses which are transmitted through the air where feces and urine are present and also Hantavirus (airborne) that can be fatal. Some of the other diseases are trichinosis, Bubonic plague, Typhoid and Weil’s disease. Packrats can also carry different bacteria like salmoneila and parasites

4. Marsh Rice Rats 

  • Marsh rice rats look somewhat common like black and brown rats. 

  • The total length of marsh rice rat is 22 to 30 cm and body mass is 40 to 80 grams.

  • It is the primary host of the Bayou virus and the most common agent of Hantavirus.

Characteristics of Rats:

Rats are generally slender with pointed heads, large eyes, prominent thinly furred ears and they have moderately long legs and sharp claws. Brown rats have a larger body compared to the house rat and its tail is shorter compared to the body and they have thicker fur and 12 pairs of mammae instead of 10 pairs. 


Female rats weigh around 350 to 450 grams and adult male rats weigh around 16 to 23 ounces.Without the tail these are round 9 to 11 inches long. Female rats are smaller than male rats. Pet rats are available  in several coat patterns and colours as they have a specialised breeding.

Male rats are usually larger than females. Pet rats are of different colours and patterns because of specialized breeding. The common colour variation rats having are brown, black, tan, gray, and white with both dark and lighter shades. Some of the most exotic colours seen in the rats are Siamese, blue, silver, black, silver faun, lilac, cinnamon, black-eyed white, cinnamon pearl, lynx, silver agouti, silver lilac, and blaze. Rat born with no tail is known as a tailless rat and the rat born with no fur is known as a hairless rats. The lifespan of rats is from 1.5 years to three years. 


Uses of Rats: 

  • Rat is used as food meat in some cultures.

  • Rats do serve a purpose in the ecosystem. They are opportunistic eaters and scavengers. They eat other things and garbage that people throw.

  • They are important in the Predatory  ecosystem as owls,Falcons,hawks and other predatory animals feed on them.

  • Some reptile  lizards and snakes also feed on rodents  such as rats .  Losing an element within an animal ecosystem can prove detrimental for the entire system.

  • Rats are also used as working animals. Some of the popular tasks include snipping of gun powder residue, demining, acting, and also for animal-assisted therapy.

  • It is used for odour detection as it has a keen sense of smell and they can be trained easily. These characteristics of rats have been used by Belgian non-governmental organization APOPO. The trained rats are used to detect the land mines and tuberculosis in the patients.

  • Rats have been kept as pets since the 19th century. Generally, brown rats are used as pet rats but sometimes black rats and giant pouched rats are also used as pets. Pet rats behave differently compared to the wild rats depending on the generation from which they are domesticated. Usually, pet rats do not have any health issues rather than pet cats and dogs.

  • Rats are also used for experimental purposes as they are proved to be valuable in physiological studies of learning and other mental processes. As well as they also help to understand group behaviour and overcrowding, a study in 2007 found that rats possess metacognition. Which is a mental ability previously only found in humans and some primates.

Natural History of Rats 

Rats are primarily nocturnal in nature (active at night) but in exceptional cases, brown rats are active in day as well as night both in rural and urban environments. All the rats are terrestrial and some of them are arboreal (Living on trees). The Sulwesian rat is an excellent climber and they exhibit the combination of arboreal traits in the genus Rattus. Most of the rats can swim and species having thick and woolly fur can generally swim well. The brown rats have the terrestrial rat characteristics and morphology and are comparatively poor climbers. But they have dense fur and readily enter the lakes and streams to hunt for fish, invertebrates or some other food. House rats are agile in nature, having the ability to climb and run on a narrow branch and electrical wire.


There is a misconception about rat species that they eat everything, But the diet of rats differs depending on the species and their habitat. House rats consume anything which is digestible and especially stored grains. Brown rats are basically omnivorous but they prefer a carnivorous diet. Depending on a wide variety of prey including shrimp, snails, mussels, insects, bird eggs and young, amphibians, eels, fish, pheasant, Pigeon, poultry, rabbits, and carrion. Many rat species living in the rainforest-like Sulawesian white rats and Hoffman’s rats eat only fruit and seeds of the fruit. Some rats from Philippine forest rats also eat insects and worms and other species of rats like rice-field rat (R. argentiventer) and Malayan field rat (R. tiomanicus) primarily they consume invertebrates found in the habitats of the forest, palm plantation and rice fields.



Before the birth of their offspring rats buildness from materials like grass branches, trash and paper or any material that can be forested from the area. Their nests are built buildings rotting trees or crevices.

Rats, generally, are baby-making machines. Brown rats can produce up to 2,000 of springs in a year . Female rats mate around  500 times in a period of 6 hours. Tropical rats have only one to six babies at once but brown rats can have 22 young at once.

Gestation period in rats lasts for 21 to 26 days and the babies weigh around 6 to 8 grams at the time of their birth. After 3 months the brown rats are ready to reproduce. The lifespan of rats is around 2 to 3 years and most house rats die within the first year of life.

Reproduction of rats is studied using the brown rats. Rats reach their sexual maturity at three months and can produce 2 - 22 young per year. They reproduce more in spring and autumn climates and their gestation period is from 21 to 26 days. Breeding in rats occurs throughout the year in some species but in other species, it might be restricted to wet season or summer months.


Rats Free Places 

There are no places on the earth without rats. They are found everywhere where humans inhabit. Antarctica is the only rat-free continent in the world because it is too cold for rats to survive outdoors. Rats are being introduced to all the surrounding islands of Antarctica because of their destructive nature. Some of the measures are taken to eradicate them. In particular birds island where breeding seabirds could be badly affected if rats were introduced. The Canadian province of Alberta is notably the largest inhabited area on earth which is free from true rats. This is because of aggressive government rat control policies.



Rats love to chew due to the fact that their teeth never stop growing, which makes them become too long. Hence it makes them impossible to eat so they keep on chewing to make some wear down their teeth. Rats are famous for chewing things like soft concrete, wood, plastics, aluminium and cinder blocks.

FAQs on Rat

1. Which are Natural Rat Repellents?

Having a dog or cats at home mostly repels the rat naturally. These rodents usually get scared because of their predators, cats can eat rats and dogs love to snatch at rats. In case you do not have one, you can place some of the hair of dogs or cats so that your home smells like you have one. Rats do not like the smell of ammonia so even ammonia can also be used as a repellent. Setting up traps for the rats is not a permanent solution to get rid of them permanently. You can use one of the methods suggested above to get relief from them forever.

2. Suggest Some Ways of Killing Rats.

There are three different effective ways of killing rats. Primarily using the traps for rats and then by placing rat poisons also known as rodenticides. Finally, the natural way to kill rats is by keeping cats in the home.

3. Which is the Largest Rat?

A species discovered in 2009 Bosavi woolly rat, which is the biggest rat discovered till date, it was 82cm long including the tail and weighs more than 1.36 kg. After comparing with the normal rats and doing scientific studies they have determined that common rats are getting larger. The positive thing of the research is that common rats physiology prevents them from becoming gigantic rats.

4. Why do rats squeak?

Rats and mice squeak and make a variety of noises. They do so to communicate with other rats and to raise  warnings when in danger.It is thought rats squeak, hiss and chatter their teeth as warnings and to indicate pain or fear.Rats will also grind their teeth, which can make noises, and they I will chew on wood other substances in the walls and on wires they use their claws and paws to scratch things which also makes noise.

5. What do rats eat?

What a rat eats depends a lot on where they are living. Rats living in the wild it's different from those who live near humans. Wild rats mostly eat grains, fruits Garden tomatoes, melons, and other sweet things. Some also eat fish and meat.

6. What is the lifespan of a rat?

Lifespan of rats depends on the species from which they belong and also whether it is kept as a pet or lives in the wild.