Predatory capabilities of rats? (And other questions)

I have a few questions about rats.

  1. What is the maximum known size of the species?
  2. What is the largest prey a single rat could take down?
  3. What about packs of rats? Could a group of rats kill a healthy adult human?
  4. Could a big rat kill a domestic cat?

Thanks in advance for any information you can give me. These critters is fascinating!

There are many many species of rats. The most common rat associated with humans is the Norway or Brown Rat, Rattus norvegicus, but the Roof or Black Rat Rattus rattus is also pretty common. The Norway rat is larger, with a maximum weight of about 450 g, or about 1 pound.

Probably something on the order of a chicken.


Probably not, except in exceptional circumstances (a very small, wimpy, old, stupid cat).

How many rats? Obviously a big enough group could take out a human. Not that this would ever actually happen.

In principle, yes, but it wouldn’t be easy. BTW, cats don’t generally attack adult rats, probably because a rat could cause them serious damage. Additionally, Norway rats are pretty non aggressive.

Wellllll, there is the Giant African Pouched Rat. They are about cat sized–so I assume that that would be a fairly even match in terms of weight. Personally I would bet on the rat simply because I would imagine a cat would generally run away first (if it survived the heart attack upon seeing a rat that DAMN big. :smiley: )

Could they take down a human? Dunno, I suspect that that depends on how many you want to include. If worst comes to worst, you could always drop a person in a pool and fill it with rats and wait for him to suffocate. :frowning:

Thought I might include some pics:

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Rats may be omnivores, but they are not predators. Only a very hungry rat would stalk and kill prey bigger than an insect. And rats will run away from virtually all predators larger than themselves. If cornered, they can inflict some nasty bites, but I doubt there’s been a documented case of rats grouping together to hunt and kill a large predator like a man.

If you want to postulate thousands of starving rats and a barefoot human in a situation where he or she couldn’t get away, possibly. But even an unarmed human can easily outrun rats, and human wearing shoes can incapacitate an awful lot of rats by stomping pretty easily. There are scenarios in which rats can overpower a healthy adult human, but they aren’t particularly plausible outside of an H. P. Lovecraft tale.

Do you have a cite for that? I thought the only mammal humans could outrun (in speed) was the possum or something. I mean, humans are the best runners, but it’s the distance, not the speed that makes us special.

No cite, but I have been able to outrun several of my family’s dogs. I would say anything smaller than a medium sized dog will lose simply due to leg length. And I doubt a rat would be able to move faster than an equally sized dog, particularly given their smaller forearms.
Certainly the idea that we can only beat a possum is false.

Humans can outrun many small animals simply because our stride is so much longer.

I haven’t found anything for rats specifically, but this table indicates a maximum speed for humans of about 28 mph, while squirrels have a maximum speed of 12 mph. Squirrels are roughly the same body size as rats, and if anything they are faster. We have trouble catching such animals not because they are faster, but because they are much more maneuverable. There’s no question even an out of shape human could easily outrun a rat.

An average human cannot sustain a 12mph running speed for long at all. Very few untrained humans could sustain this 5min/mile speed for more than a few 100 metres, if that. In fact, even for trained humans, this is a pretty quick clip. If a rat can indeed sustain 12mph for a few 100 metres, then the rat would be able to outrun most humans.

Well, after a quick check of the literature (never let it be said that I won’t pursue the futile), it seems that rats are actually pretty slow. Even trained rats are slower than 35m/min, measured as the fastest speed they can sustain over the last 10mins of a 1hr run (Rossiter et al., 2005; J Physio 565: 993-1005). According to Sullivan & Armstrong (1978: J App Physiol 44: 358-368) a ‘fast gallop’ of c.73m/min (<3mph) is around 150% of VO2 max for rats, and this rate can be sustained for at least 2.5 mins. Although an unfit human would have trouble running at 12mph, 4-5mph is plausible - and so an average human should indeed be able to outrun an average rat without difficulty.

Well, the very idea of a pack of rats attacking a human is fairly stupid, so it’s not as if we’re in the realm of reality anyway. I doubt that ‘stomping’ rats is easy, and if they climb up your body, things get more fun still. However, in reality, certainly a human will be not be killed by a pack of rats unless something very odd is going on.

I agree, not a healthly alert human- unless they completely went bonkers in a panic attack.

However, a drunk passed out in an alley could be in trouble.

Rats are definitively scavengers. They might bite in defense or to protect territory, and they’ll attack and kill each other over food and dominance, but the only way they would be compelled to “attack” an animal as large as a man is if he were incapacitated (and they were hungry). Even the nutria (a large, aquatic rat-like creature native to South America but imported into the American South for their fur) might be aggressive toward Jimmy Carter, but likely wouldn’t stand up to a 10 year old girl yelling. One telling point is their vision; the common rat has about six feet of usable vision and maybe another twenty feet where they can distinguish anything at all. In contrast, virtually all land predators have excellent binocular vision with which to identify prey before being discovered themselves.

Rats are surprisingly intelligent (or perhaps not…we share that common scavenger heritage and it seems to have worked well for us) and can make excellent pets. They’re at least as intelligent as a cat and if properly socialized can be quite friendly. Just don’t line their cage with pages out of a Lovecraft story. :wink:


Quite so. I should have explained a little more fully that I assumed the 12 mph figure, being the maximum rate, greatly exceeded the speed a rat could run over a sustained distance. In fact, it seems that a human’s max rate (28 mph) exceeds the sustained rate (lets say 6 mph) by approximately as much as the 12 mph figure exceeds the rat’s sustained rate (3 mph). A human could outdistance a pack of rats with a quick sprint and then easily stay ahead of them at an easy jog or even a brisk walk.

We’re into the realm of nitpicking minutae, but the 28mph max for humans is not a realistic figure, either, being the top speed for a handful of the world’s best athletes. I’m a trained distance runner, and I think my max speed is well under 20mph, perhaps as low as 16mph. Also, the 3mph figure for rats was for a 150% VO2 max effort, which is not sustainable for long anyway.

But the basic story is … details aside, you are quite correct that pretty much any human can outrun pretty much any rat, under normal circumstances. I was slightly suprised that rats are so slow; my pet rats seem quicker than the science suggests.

They are quite clever critters though, as Stranger says - perhaps they could take out a human by building an elaborate death ray out of piss and bits of string…

If we’re nitpicking, it’s the maximum rate for humans, then, isn’t it?

Ha ha ha - this one could run and run …

In the last couple of posts you referred to “a human’s max rate” as being c.28mph, which would only be true if a 100m runner was racing the rat. You did say earlier that 28mph was the max speed “for humans”, but even so, the rat-race scenario would only hold if Maurice Green was lining up on the start line with the rat - which would be a 100m race I’d pay to see…

Anyway, if we use the 28mph figure, we should also use the figure from a highly trained racing rat.

Oh nonsense. Try actually reading my posts. All I said was that a human’s maximum rate was 28 mph (which is true), which I mentioned in order to give an approximate basis for comparison. I never said that any human trying to outrun a rat would be going 28 mph. For that matter I never said a human would be going even 12 mph. All I said was that a human could outrun a rat, a conclusion which I based on the great disparity between the maximum listed speeds for both.

Right, that does it, nitpicking dials to 11:

  1. The maximum speed you cited for humans is not a representative maximum speed for any given human. It is the approximate maximum for a highly trained individual, for which there is no equivalent in ratdom, given that rats don’t head off down the track to do their parachute training and weights. Comparing apples and rat-shaped oranges.

  2. The maximum speed is wrong anyway. The fastest peak speed ever attained is more like 26.5mph. In fact, your link didn’t state whether the speeds were peak speeds, sustained speeds over some distance, or what.

  3. There was - and is, AFAIK - no ‘listed maximum speed’ for a rat, although the cites I provided gave some indication of relatively fast rat-running speeds, and the speeds a rat could sustain over an extended period. You extrapolated from a squirrel, and your extrapolation was, in fact, completely inaccurate - well, assuming the 12mph figure for squirrels is correct. Who knows if that’s the case, what with their bleedin’ fluffy tails and lack of traction control…

  4. This was imprecise, too: “fact, it seems that a human’s max rate (28 mph) exceeds the sustained rate (lets say 6 mph) by approximately as much as the 12 mph figure exceeds the rat’s sustained rate (3 mph)”. Not so, the maximum and sustained rates are approximately in the same proportions for rat and human, however the amounts (wrt ‘as much as’) by which the max exceeds the sustained are quite different.

You wouldn’t let it lie, would you…

So what? Doesn’t affect my point.

Off by about 6%. Doesn’t affect my point.

Well, yeah, OK, the rat is even slower than the squirrel. Reinforces my point.


:rolleyes: :rolleyes: :rolleyes:

So what, exactly, is your point in all this, since you agree with me on the basic conclusion?