# Rat (*Rattus norvegicus*)

> 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.

- **Category:** Mammal
- **Conservation status (IUCN):** Least Concern
- **Range:** Probably originated in northern China and Mongolia; the brown rat is now found worldwide near people on every continent except Antarctica.
- **Canonical page:** https://globalanimalguide.org/animals/rat/
- **Last reviewed:** 2026-07-16

## Scientific classification

- **Kingdom:** Animalia
- **Phylum:** Chordata
- **Class:** Mammalia
- **Order:** Rodentia
- **Family:** Muridae
- **Genus:** Rattus

## Facts at a glance

| Attribute | Value |
| --- | --- |
| 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) |

## 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.

## Frequently asked questions

### 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.

## Sources

- [IUCN Red List — Rattus norvegicus.](https://www.iucnredlist.org/search?query=Rattus%20norvegicus&searchType=species)
- [Animal Diversity Web — Rattus norvegicus. University of Michigan Museum of Zoology.](https://animaldiversity.org/accounts/Rattus_norvegicus/)
- [Wikipedia — Rat.](https://en.wikipedia.org/wiki/Brown_rat)

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Source: Global Animal Guide (https://globalanimalguide.org/animals/rat/). Licensed CC BY-NC 4.0 — free for non-commercial reuse with attribution.