By now, of course, you've run to cover every single tiny opening in your house to keep the unceasing, steady advance of the rats at bay. But that's cool by the rats, friend; they can always just chew directly through your walls.

IRRI images In conclusion, rent property in the vacuum of space.

God, with his famously twisted sense of humor, decided to give rats inordinately strong jaw muscles, which are positioned in such a way on their skulls as to make them even more effective. So while rabbits enjoy a good piece of wood, rats have no problem going to town on brick, cement or lead. That's probably because the enamel of rat incisors is harder than platinum and even iron. In fact, because a rat's teeth never stop growing, even through their own skull, they actually have to eat your house, or die.

There are now thought to be around 80 million rats in Britain, a rise of more than 200 percent since 2007. (Note: These are 2009 numbers; 2011 numbers are written entirely in rat cuneiform, and sadly, we cannot translate them.) Even with modern pest-control methods, it's estimated that there is at least one rat per person in major cities like New York. In fact "a rat per person" is actually an official government means of estimating how many there are in a given place, and not just the worst campaign promise we've ever heard.

Wikipedia "Don't listen to him! We'll have GIANT RATS. On our MOON BASE."

Then they tried to catch him.

Despite laying over three dozen traps, calling in two dogs trained exclusively for the job and digging 15 "tracking tunnels," the researchers couldn't nab one little rat. They couldn't even get close. Even worse, at some point the rat actually managed to lose or break his tracking device, so they had no idea where he was anymore. When they eventually found Rat McClane, 18 weeks later, it was on an entirely different island over a quarter of a mile away. Until then, we had no idea rats could even swim that far.

So hey, you saw a rat in your place? Good luck finding it, when all the collective forces of technology and science have tested their mettle against it and were found wanting. But no, we're sure you and your "tie a tiny lasso and try to throw it around him" approach will have no difficulty eradicating that pest.

Wikipedia Watch out! He's going for the box cutter!

Just one tiny problem: Even if you catch it ...

But wait, how does this apply to rats? They're tiny little rodents. We kill them with a spring and a bit of metal. Rats aren't invincible ... right? Oh God, please tell us that's right, next sentence ...

Ha ha, not even close, pussies! In certain ways, rats are god damn immortal. For instance, what's the most surefire way you can think of to kill a rat? Poison, right? Well, to start with, rats only eat a small amount of any new food source at first, to make sure it doesn't make them ill. That's right: They caught on. They know you're trying to kill them, and are taking measures to correct that ... mistake.

Daz "Well, you eat one poison chocolate, and then suddenly you've eaten the whole box, right?"

On top of which, humanity is starting to come up against an entirely new strain of rat, something scientists are comfortingly calling "genetically mutated super rats," which are immune to almost every type of poison.

Alexey Krasavin "We must be in a recession. This is the shittiest cyanide I've ever tasted."

Dang! You know shit is getting real when even famously stoic science starts naming their new species like comic book villains.

...

And so do rats.

Wikipedia "Everyone goes to sleep eventually."

Sure, we all know that rats will take a few bites from corpses. (Thanks, CSI! That and "semen on everything." That's all we took away from your show.) But that's just because they're scavengers, right? Rats aren't picky when it comes to their food sources, everybody knows that. But that's not entirely true. There is one thing rats seem to love more than anything else, and given the chance they will risk everything to get it again and again: your blood.

They're basically a bunch of furry little vampires that live in your walls. A 22-year study of urban rat bites found that the most common time to be bitten was between midnight and 8 a.m., while sleeping peacefully in your own bed, unaware that a huge, diseased rodent was chewing on your face. Oh, and that's not hyperbole, either: Rats most commonly go for the face and hands.

Wikipedia This is why you don't teach them to sit on your shoulder. Or gnaw on your ears.

But this is like spiders, right? They might bite you once or twice, but it's either in self-defense or desperation. It's not like they routinely prey on human bei- of fucking course it's like that. Haven't you been paying attention to this article? Once someone is bitten by a rat, their chances of being bitten again dramatically increase.

But ... but why? If it's not defense, and there's plenty of other food, why on earth would they do it?

Wikipedia Vengeance.

We actually told you the answer already. It's just that the part of your brain responsible for keeping anxiety in check told you it was a joke. Rats will repeatedly attack the same victim because they seriously and literally want your blood.

In 1945, Professor C.P. Richter did a study to see what exactly attracted rats to humans. He gave a group of rats access to a large quantity of blood, and found that within 24 hours they had consumed it all, even though it was four times as much "food" as they would normally eat in a day. Richter's actual, word for word scientific conclusion: "[Rats can develop] a real craving for fresh human blood."

You think you can pacify them with milk, but when rats have their own temple, you know it's only a matter of time.

And, it bears repeating, these are the things that might be climbing up your toilet right at this very moment. Soooo ... might be time to invest in a good, solid, waterproof safe, eh?

For more animals we need to annihilate, check out The 5 Most Horrifying Bugs in the World and 6 Animals Humanity Accidentally Made Way Scarier.