The 10 Largest Rats In The World

Written by Hannah Ward
Updated: October 4, 2021
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Rats are possibly one of the most widespread rodents around the world and are found pretty much wherever there are humans, with the exception of Antarctica which is too cold for them.  Often classed as a pest, they are extremely adaptable and can live in a wide range of habitats, including swampsrainforests, and fields.  With more than 60 species there is sure to be a range of sizes, with the average body size being 5 inches (not including the tail), but some can be much, much bigger.  But just how big can they get?  Here we have listed 10 of the largest rats in the world by body size.

#10: Tanezumi Rat

The first rat on our list is the Tanezumi rat which is also sometimes called the Asian rat and has a body size of 8.25 inches, not including the tail.  Found predominantly across Asia, the Tanezumi rat is closely related to the common black rat and has a similar appearance with dark brown fur.  Although they are often found in towns, they are generally associated with the destruction of banana, coconut, and rice crops, with rice being their main diet in agricultural areas.

#9: Red Spiny Rat

Largest rats - red spiny rat
Red spiny rats can reach more than 8 inches in length

Evgeny Haritonov/Shutterstock.com

The red spiny rat is only slightly larger than the Tanezumi rat, reaching a maximum size of 8.26 inches, and is typically found in a forest habitat where it eats fruit, plants, and insects.  They are found widely across Asia, including in ThailandMalaysiaMyanmar, and China. Red spiny rats have distinctive red-brown fur and a much lighter belly which is usually either white or pale yellow.  They also have “spines” on their back which is where they get their name from.  These spines are stiff hairs that stand up amongst the rest of their fur.

#8: Bushy-Tailed Wood Rat

The bushy-tailed wood rat, also known as a packrat, is easily distinguished by its unusually bushy tail, which is similar to that of a squirrel, unlike the hairless tails that most other rats have.  They grow to a body length of around 8.7 inches and are usually brown with white bellies and feet and their ears are also much rounder than those of other rats.  Although they prefer rocky areas, bushy-tailed wood rats are extremely adaptable and can live in both forests and deserts and are able climbers.  They are native to the US and are found across the western regions North America and also in parts of Canada.

#7: Lesser Bandicoot Rat

Largest rats - lesser bandicoot rat
Lesser bandicoot rats live across southern Asia

Despite their name, the lesser bandicoot rat is not actually related to bandicoots which are marsupials from Australia.  Instead, these large rodents are found across Southern Asia, including India and Sri Lanka and grow to a length of 9.85 inches.  They are most famous for the grunts that they make when they are attacking or excited which have been compared to those of a pig.  Lesser bandicoot rats are quite aggressive animals, especially when they are threatened and as well as grunting they have long guard hairs along their back which stand up to make them look more intimidating.  They live underground in burrows, usually on or near farmland and they are classed as a pest as they are extremely destructive to crops.

#6: Brown Rat

Brown Rat portrait
Brown Rat

Heiko Kiera/Shutterstock.com

The brown rat, which is also known as a common rat or sometimes a street or sewer rat, is one of the most common species of rat around the world.  Originating in China, they are now found everywhere except Antarctica and are largely classed as a pest.  Although they are called the brown rat they can be dark grey and they can reach a body size of 11 inches with a tail that is only slightly shorter than its body length.  They are often found in urban areas and will eat virtually anything that they find, from leftover food to small birds.

#5: Mountain Giant Sunda Rat

The mountain giant Sunda rat, also known as the giant rat of Sumatra, comes in at a length of around 11.5 inches excluding its tail which can be a further 10 to 12 inches long.  Their natural habitat is in forests high up in the mountains of Indonesia and Malaysia.  They are usually dark brown but sometimes have lighter brown spots on them and a layer of guard hairs which acts as a protective layer and can repel water as well as protect them from the sun.  The mountain giant Sunda rat is, like most other rats, an omnivore and eats insects and small birds as well as plants and fruit.

#4: Northern Luzon Giant Cloud Rat

Largest rats - Northern Luzon cloud rat
Luzon giant cloud rats can reach 15 inches in size!

The northern Luzon giant cloud rat is endemic to Luzon, an island in the Philippines and can reach a body size of 15 inches.  They have a particularly unique appearance and don’t even really look much like rats at all – instead they have long fur, small ears and a bushy tail.  They are usually black and white, but can be various shades of grey, or occasionally completely white.  What makes these rats even more different from their counterparts is that they spend the majority of their time in the upper branches of trees in the rainforests.  With large back feet and long claws they are able climbers and even give birth in hollows in trees.

#3: Bosavi Woolly Rat

Deep in the jungle in the heart of Mount Bosavi, an extinct volcano in Papua New Guinea, hides a species of rat so new that it doesn’t even have an official scientific name yet.  Inside the crater where the sides are half a mile high and the wildlife is virtually locked inside is a species known only as the Bosavi woolly rat which was discovered in 2009 during the filming of a wildlife documentary.  This species had never been seen before until a 16 inch long giant with a tail as long again literally wandered into the camp.  The Bosavi woolly rat is dark grey or occasionally brown and has thick fur which gives it a woolly appearance.  Little else is known about them but it is thought that they eat mostly plants and vegetation.

#2: Gambian Pouched Rat

Largest rats - Gambian pouched rat
Gambian pouched rats are the second largest rat species in the world!

iStock.com/Farinosa

Coming in at a close second is the Gambian pouched rat with a body size of 17 inches and an unusually long tail that can be a further 18 inches long.  Also known as the African giant pouched rat, they are widespread across most of Africa but are classed as an invasive species in Florida after some pets escaped and subsequently bred.   Their upper bodies are dark brown while their bellies are grey or white, and they also have a white tip on their tail.  They have pouches in their cheeks like hamsters which is where they get their name from.  They have an excellent sense of smell and there is an organization in Tanzania that trains them to detect both land mines and tuberculosis.

#1: Sumatran Bamboo Rat

Largest rats - bamboo rat
Bamboo rats are the largest rats in the world

rweisswald/Shutterstock.com

The Sumatran bamboo rat is the largest rat in the world with a body size of 20 inches.  These rats have unusually short tails compared to their body length (only 8 inches) which makes them smaller nose to tail than the Gambian pouched rat, but larger in body length and weight (8.8 pounds).  The Sumatran bamboo rat is found mainly in China, but also in Sumatra.  These giants are usually dark brown but are sometimes grey and have small ears on a quite round head, short legs, and a bald tail.  Sumatran bamboo rats prefer to live in burrows, rarely coming above ground, and are able to eat the roots of plants, using their system of burrows to find food.  As the name suggests, they feed mostly on bamboo, but also on sugar cane, and as such are viewed as pests due to the damage that they cause to crops.

Bonus: The Largest Rat Ever!

While the largest rats today live in forests in Southeast Asia, a far larger species once roamed the jungles of the Indonesian island of Timor. Excavated skeletons of the genus Coryphomys reveal a rat species that could have reached 13.2 pounds in weight. Just imagine a rat the size of a border terrier!

This size makes Coryphomys the largest rat ever recorded. The genus is extinct today, but distant relatives can still be found on islands like New Guinea.

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About the Author

I'm an avid animal lover, and when not writing I can be found on my farm surrounded by dogs, horses, and sheep.