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Global Animal Guide
Brown rat with brown-grey fur and a long tail alert on a wooden surface
Mammal Least Concern

Rat

Rattus norvegicus

Quick answer

The brown rat, also called the Norway rat, is a large, highly intelligent rodent that lives alongside people across most of the world. It has coarse brown-grey fur, a blunt snout, and a long scaly tail, and it thrives in sewers, cities, farms, and waterways. Brown rats weigh up to about 500 g, are strong swimmers and climbers, and usually live one to two years in the wild.

By the Global Animal Guide editorial team Last reviewed How we research & review

Rat facts at a glance

Key facts about the Rat
Scientific name Rattus norvegicus
Diet Omnivore (highly opportunistic)
Habitat Cities, sewers, farms, riverbanks worldwide
Lifespan 1–2 years in the wild
Weight 200–500 g (7–18 oz)
Top speed 13 km/h (8 mph)
Conservation status Least Concern (IUCN)
Scientific classification
Kingdom Animalia
Phylum Chordata
Class Mammalia
Order Rodentia
Family Muridae
Genus Rattus

Where it lives

Probably originated in northern China and Mongolia; the brown rat is now found worldwide near people on every continent except Antarctica.

Native range (approximate)

What is a group of rats called?

Group name (collective noun)

A group of Rats is called a mischief. It is also known as a colony or a swarm.

Baby name

A baby Rat is called a pup. It may also be called a kitten or a pinkie.

Explore more animal collective nouns and baby animal names .

Intelligence and behaviour

Brown rats are among the most intelligent rodents, capable of learning routes, solving simple puzzles, and even showing signs of empathy in laboratory studies. They are highly social, living in colonies with a clear hierarchy, and they are famously neophobic — wary of new objects and foods in their environment, which makes them difficult to trap or poison. They are also excellent swimmers and can climb, gnaw through tough materials, and squeeze through surprisingly small gaps.

Diet and adaptability

As opportunistic omnivores, brown rats eat almost anything, from grain, fruit, and seeds to meat, refuse, and insects. This flexible diet, combined with rapid breeding and a tolerance for human environments, has made the brown rat one of the most successful mammals on the planet. A colony can grow quickly wherever food and shelter are available.

Range and history

The brown rat probably originated in northern China and Mongolia and spread worldwide by stowing away on ships and in cargo, reaching Europe in the 1700s. Today it is found on every continent except Antarctica, usually close to people. Its smaller relative, the black rat, was historically linked to the spread of plague, while the brown rat is the species most often seen in modern cities.

Rats and people

Brown rats have a complex relationship with humans. In the wild they are treated as pests because they damage stored food, gnaw structures, and can carry disease. Yet the same species, bred as the fancy rat, is a popular and affectionate pet, and laboratory strains have been central to advances in medicine, psychology, and genetics.

Dig deeper into the Rat

Explore the Rat

Did you know? Rat facts

  • The brown rat, also called the Norway rat, is a large, highly intelligent rodent that lives alongside people across most of the world.
  • A group of rats is called a mischief. A baby rat is called a pup or kitten, and a newborn without fur is sometimes called a pinkie.
  • Yes. Brown rats are very intelligent — they can learn routes and tasks, solve simple problems, and remember solutions. This intelligence and their wariness of new things make wild rats hard to trap.
  • Rats can carry organisms that cause illnesses such as leptospirosis and, historically, plague (mainly linked to the black rat). Good hygiene and pest control reduce the risk; pet rats from reputable sources are generally safe.
  • Wild brown rats usually live only one to two years because of predation, disease, and harsh conditions. Well-cared-for pet rats often live around two to three years.
  • Conservation: Least Concern (IUCN).

Diet & feeding

Rat feeds primarily as a omnivore (highly opportunistic). As opportunistic omnivores, brown rats eat almost anything, from grain, fruit, and seeds to meat, refuse, and insects. This flexible diet, combined with rapid breeding and a tolerance for human environments, has made the brown rat one of the most successful mamm

Adaptations

  • Brown rats are among the most intelligent rodents, capable of learning routes, solving simple puzzles, and even showing signs of empathy in laboratory studies. They are highly social, living in colonies with a clear hierarchy, and they are famously neophobic — wary of new objects and foods in their environment, which makes them difficult to trap or poison. They are also excellent swimmers and can climb, gnaw through tough materials, and squeeze through surprisingly small gaps.
  • As opportunistic omnivores, brown rats eat almost anything, from grain, fruit, and seeds to meat, refuse, and insects. This flexible diet, combined with rapid breeding and a tolerance for human environments, has made the brown rat one of the most successful mammals on the planet. A colony can grow quickly wherever food and shelter are available.

Behaviour & ecology

  • Brown rats are among the most intelligent rodents, capable of learning routes, solving simple puzzles, and even showing signs of empathy in laboratory studies. They are highly social, living in colonies with a clear hierarchy, and they are famously neophobic — wary of new objects and foods in their environment, which makes them difficult to trap or poison. They are also excellent swimmers and can climb, gnaw through tough materials, and squeeze through surprisingly small gaps.
  • As opportunistic omnivores, brown rats eat almost anything, from grain, fruit, and seeds to meat, refuse, and insects. This flexible diet, combined with rapid breeding and a tolerance for human environments, has made the brown rat one of the most successful mammals on the planet. A colony can grow quickly wherever food and shelter are available.
  • The brown rat probably originated in northern China and Mongolia and spread worldwide by stowing away on ships and in cargo, reaching Europe in the 1700s. Today it is found on every continent except Antarctica, usually close to people. Its smaller relative, the black rat, was historically linked to the spread of plague, while the brown rat is the species most often seen in modern cities.

Communication

  • Rat uses scent, posture, and vocal signals to mark territory and coordinate social behaviour.
  • Communication intensity often peaks during breeding seasons and territorial disputes.

Habitat & range

Cities, sewers, farms, riverbanks worldwide

Ecological role

Rat plays a recognised ecological role in cities, sewers, farms, riverbanks worldwide.

Frequently asked questions about the Rat

What is a group of rats called?

A group of rats is called a mischief. A baby rat is called a pup or kitten, and a newborn without fur is sometimes called a pinkie.

Are rats intelligent?

Yes. Brown rats are very intelligent — they can learn routes and tasks, solve simple problems, and remember solutions. This intelligence and their wariness of new things make wild rats hard to trap.

Do rats spread disease?

Rats can carry organisms that cause illnesses such as leptospirosis and, historically, plague (mainly linked to the black rat). Good hygiene and pest control reduce the risk; pet rats from reputable sources are generally safe.

How long do rats live?

Wild brown rats usually live only one to two years because of predation, disease, and harsh conditions. Well-cared-for pet rats often live around two to three years.

Can rats swim?

Yes. Brown rats are strong swimmers that can paddle for long distances and even tread water for days. They often live along waterways and in sewers, and can enter buildings through drains.

What is a baby rat called?

A baby Rat is called a pup. It may also be called a kitten or a pinkie.

Sources & references

This guide is compiled and reviewed against established zoological and conservation references. Key sources for the Rat:

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