Can rats be as big as cats?

We often read in the news media about rats being so big that they are as big as cats. Can this be true? Are people exaggerating? People tend to exaggerate when they are frightened of something. It happens all the time. Normally exaggerating the size of an animal occurs when people spot a mysterious wild cat in the distance in the half-light. It’ll be a moggy, a domestic cat but if it’s a big moggy a frightened person might see a mountain lion instead.

The same perception occurs with respect to rodents sometimes. Bethany Brookshire, the author of “Pests: How Humans Create Animal Villains”, firmly believes that people exaggerate the size of rats because they are scared of them.

She makes it clear that there has been no record of a wild, brown Norwegian rat above the weight of 2 pounds. She talked of a colleague, a rodentologist, Bobby Corrigan, who carries around a cheque for $500 which he will give to anybody who can hand to him a 2-pound rat and he has never given away the money.

Two useful tags. Click either to see the articles:- Toxic to cats | Dangers to cats

Good point. But I’ve been doing some digging around and the picture painted by Bethany Brookshire is not quite complete.

World’s smallest cat

The world’s smallest cat is not a domestic cat but a wild one: the rusty-spotted cat. It is said to be around half the size of a domestic cat. My research indicates that the smallest individual rusty-spotted cat on record weighed 0.8 kg which is 1.76 lbs. Another example weighed 0.9 kg which is just short of 2 pounds. I think we can say that the rusty spotted cat weighs about 2 pounds.

Rusty-spotted cat
Rusty-spotted cat. Cute yes. Not cute to own one though. Pic in public domain on Reddit.

As you can see, therefore, the smallest cat in the world is just slightly larger according to Bethany Brookshire than a potentially exceptionally large Norwegian brown rat.

Bosavi woolly rat

But the story doesn’t stop there because there are larger rats but they are very rare. In 2009, the Independent newspaper reported the discovery of a species of rat “as big as a cat”. Just another media exaggeration? Not quite because this rat was almost 3 feet long and it weighed 3.3 lbs. They named it the Bosavi woolly rat. It was found trapped inside the crater of Mount Bosavi in Papua New Guinea, a sort of lost world where there were 39 other undiscovered species.

So, this particular rat if it genuinely still exists is bigger than the smallest feline in the world.

Related rat species

It appears, too, that another species of rat closely related to the giant woolly rat that I have mentioned found in the same area can weigh up to 1.4 kg. The picture just below is of this rat being held by a man to allow you to scale its size. 1.4 kg is 3 pounds.

Rare giant rat related to the woolly rat from Papua New Guinea. Image in public domain.

This species the rat is therefore bigger than the smallest cat and certainly as big as a cat provided that particular cat is the world’s smallest!

That’s the full picture as I see it. The summary is below.


To summarise, very rare species of rat can be as big as if not bigger than the world’s smallest cat which is a wild species called the rusty-spotted cat.


It has to be admitted, though, that in general day-to-day life even the very biggest rat is not as big as a cat if we are referring to a standard adult cat. Normally, the biggest Norwegian brown rat is going to be as big as a sub-adult domestic cat certainly but not an adult one. However, there will be some individuals who are exceptional such as the one below. This one looks like it weighs as much as the rare species mentioned above.

This is a standard rat captured in Sweden where it had been feeding on rubbish tips. It is enormous but exceptional.
This is a standard rat captured in Sweden where it had been feeding on rubbish tips. It is enormous but exceptional. Screenshot from video.

Described as Britain’s biggest rat, the one below was caught by a rodent catcher: TP Pest Control Services. It is as big as a rusty-spotted cat I’d say.

Described as Britain's biggest rat
Described as Britain’s biggest rat. Image: TP Pest Control Services

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