Rat

Rat facts at a glance

How big is a rat?

An adult rat measures 25 cm long — about 14% of the height of an average adult person (1.73 m) — and weighs around 500 g, about 1% of an average adult’s body weight (70 kg).

What is a group of rats called?

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.

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.

Conservation status of the Rat

Sources & references

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

• IUCN Red List of Threatened Species

  Conservation status (Least Concern) reflects the IUCN Red List category for Rattus norvegicus.

• iNaturalist — observations & photos

  Search citizen-science observations and community IDs for Rattus norvegicus. Useful for range checks and recent sightings — not a substitute for formal Red List status.

• GBIF — occurrence data

  Global Biodiversity Information Facility species search for Rattus norvegicus. Explore published occurrence records used in range research.

• IUCN Red List — Rattus norvegicus.

  Conservation status (Least Concern) and population trends.

• Animal Diversity Web — Rattus norvegicus. University of Michigan Museum of Zoology.

  Life history, morphology, and range.

• Wikipedia — Rat.

  General taxonomy and overview (cross-check primary sources).

• Global Animal Guide editorial standards

  How we research, source, review, and update every guide for accuracy.