People often mean very different animals when they ask how many types of rats there are. If you use the word rat in the everyday sense, you might talk about familiar species, pet varieties, lab strains, or even rodents that only look rat-like.
The count depends on what you include, because true rat species are only part of a much larger group of rodent species that people call rats. Some lists stay within the genus Rattus, while others add unrelated animals with rat in their common name.
The Short Answer And Why The Number Varies
The word rat is a common name, not a strict scientific label. In the order Rodentia, the family Muridae contains the genus Rattus, which includes many of the best-known true rats.
Other rodent species get called rats because they resemble them.
What Counts As A True Rat
A true rat is usually a species in the genus Rattus. That group includes the brown rat and black rat, along with many lesser-known species found across Asia, islands, and other regions.
A widely cited count puts the world total at 56 known rat species, though taxonomic updates can change that number.
Why Common Names Create Confusion
Common names stretch the word rat far beyond Rattus. Pack rats, kangaroo rats, bandicoot rats, and similar animals may share the name, yet they are not all closely related.
That is why one answer might count only true rats, while another counts every rodent with rat in its name.
How Scientists Group Rats Within Rodentia
Scientists sort animals by genetic relationship, not by everyday labels. Within Rodentia, rats are grouped by family, genus, and species.
The number of “types” changes depending on whether you mean species, subspecies, strains, or informal name groups.
The Main Species Most People Mean
When most people ask about rats, they usually mean the species most likely to live near people or be seen in homes, cities, farms, or ports. The best-known examples come from the genus Rattus.
Brown Rat Or Norway Rat
The brown rat, also called the Norway rat, sewer rat, or wharf rat, is Rattus norvegicus. It is one of the most familiar rats in the US and around the world.
This species thrives in dense human environments.
Black Rat Or Roof Rat
The black rat, also called the roof rat or ship rat, is Rattus rattus. It is lighter-built than the brown rat and often climbs well, which is why people commonly associate it with roofs, attics, and ships.
Like the brown rat, it can be part of rat infestations and is tied to older stories about plague and bubonic plague spread through fleas on infected rats.
Polynesian Rat And Other Rattus Species
The Polynesian rat, Rattus exulans, is another widespread Rattus species. The genus includes many regional species that most people never encounter.
Urban And Invasive Rats Around People
In cities, urban rats usually mean brown rats and black rats. Both species have become successful invasive species in many parts of the world.
Large rat populations can damage food supplies and spread illnesses such as leptospirosis and hantavirus. Public-health risks also include disease pressure connected with rat infestations, which is one reason pest control focuses so heavily on these two species.
Animals Called Rats That Are Not The Same Kind
Some animals called rats are not true Rattus rats. They may be close relatives, distant rodent cousins, or animals that share only a rat-like body shape or lifestyle.
Pack Rats And Woodrats
A pack rat, also called a packrat, woodrat, or wood rat, belongs to the genus Neotoma. These rodents collect objects and build middens, which are nest heaps and storage piles that can last for years.
Kangaroo Rats And Other Distant Relatives
Kangaroo rats belong to Dipodomys in the family Heteromyidae, so they are not true rats. They have long hind legs and can jump, which makes them very different from city rats even though the common name overlaps.
Cotton Rats Rice Rats And Bandicoot Rats
A cotton rat belongs to Sigmodon, while a rice rat can refer to several rodent groups depending on region. Bandicoot rat usually points to Bandicota, and some species such as Rattus argentiventer get included in regional rat discussions.
You may also hear names like bush rat (Rattus fuscipes) and swamp rat (Rattus lutreolus), which show how broad the common-name pattern can be.
Pet And Laboratory Forms People Often Count Separately
People often count pet and lab rats separately from wild species because these are usually varieties, strains, or bred lines rather than naturally occurring species. That makes the total look much bigger, even when the animals still trace back to a small number of true rat species.
Fancy Rats As Domesticated Norway Rats
A fancy rat or pet rat is usually a domesticated rat bred from the brown rat, so it is still a Rattus norvegicus. These domesticated rat lines have been kept as rats as pets for generations and can behave very differently from wild rats.
Common Pet Varieties Like Dumbo Rex And Hairless
Pet owners often count dumbo, dumbo rat, rex, rex rat, hairless, and tailless forms as separate types. These differences come from coat color, ear placement, tail length, and other inherited traits, not from different species.
Laboratory Strains Such As Wistar Sprague-Dawley And Long-Evans
Laboratory rats usually get named by strain, such as wistar rat, wistar, sprague-dawley, and long-evans. Researchers track the rat genome and use controlled breeding for consistency, while groups like afrma help set standards for fancy rat breeding and showing.
Special Cases Like African Giant Pouched Rats
People often call some animals rats even though they are not standard pet or lab rats.
The giant pouched rat, also known as the African giant pouched rat, belongs to Cricetomys. Organizations such as apopo use this animal for detection work.
Other rodents like cricetomys gambianus and the spiny rat show how wide the rat label can stretch when you consider behavior, appearance, and use instead of strict taxonomy.
