(rats chittering) (eerie music) - [Geoffrey] For years, the Orkin pest control company has branded Chicago the rattiest city in America.

- We're gonna start in the end of the alley there.

- Okay.

- [Geoffrey] Josie Cruz says Orkin's claim is nonsense.

Just a marketing gimmick.

But she doesn't deny that Chicago has a rat problem and it's her job to lead the centuries-old battle against them.

- So we're here in this alley because we had a request for it to be baited because there's been some rodent activity.

- So someone, we're looking, but- - Right.

- Someone saw rats here.

- Well, yeah.

(dog barking) And there's different reasons why there's rats.

That's one sound that you hear there.

- The dog?

- A dog.

If they don't pick up after the dog, then you're gonna have a problem.

- Why?

I mean, I don't wanna get too graphic, but why?

- Because they'll eat the, you know, the dog poop.

They'll eat it.

Yeah.

- Like a vitamin.

- Yeah, it's good.

It's protein for them.

(playful music) - [Geoffrey] And the biggest invitation of all to a rat party is an open trash container.

- This, see this right here?

- Oh, look at that.

- This is a prime example of the rats just coming in here.

- Oh, and the bag is just there.

- [Josie] Yep, yep.

That's just perfect.

This is just a perfect spot for them.

- And can a rat get in a hole, like, that big?

- [Josie] Yes.

Quarter-size.

- [Geoffrey] A quarter-size hole.

A rat can squeeze through, like, a little hole like that?

- They're very smart.

- Do you kind of respect them?

- No, I kill them.

(everyone laughs) (upbeat music) - Josie's team member, Steve Genaro, shows us the low tech tools of his trade.

Let me see this.

So you cut a slit in the broomstick, you put the spoon in, you wrap it in electrical tape, and put a hose clamp on it.

- Dollar Tree special.

- Yeah.

- You really are saving the taxpayers money with that contraption there.

- [Josie] But it works.

- One scoop.

- Yeah.

- It's two ounces.

- And what is this stuff?

- It's a bromadiolone.

And what it is, the rat is going to eat this and then they're gonna bleed out.

(cartoon rat growling) - And how lethal is that to people?

- It isn't.

A person, a dog, a cat, human would have to eat half their body weight.

There is an antidote for this.

It's a vitamin K1.

- Now, rats are smart.

Do they stockpile vitamin K1 in their burrows?

- No, they don't.

- They're like, "Hey, Marty, get some vitamin K1!"

- Not that we know of.

We haven't been down there, so we don't know.

- And they, like, nest?

Thanks to Steve and Josie, I'm learning that an innocent gap in the pavement might be something more sinister.

Oh yeah, that's a big one.

- [Josie] It's a perfect hole right there.

Perfect burrow.

- Wow.

(upbeat music) So when you hear people say, "Oh, I've seen a rat the size of a cat," is that an urban myth?

- Yes.

- [Geoffrey] There are no rats the size of a cat?

- [Josie] No.

No.

- [Geoffrey] What's the biggest rat you've ever seen?

- I mean, we see big ones.

(sinister music) I think people get scared and they just think it was that big.

- There's so much to know here.

Do you get creeped out by rats?

- I don't, but don't put any ants or a spider in front of me, 'cause I'll run.

I'll run real fast.

- [Geoffrey] Do you like doing this?

- Yeah.

- Yeah?

What do you like about it?

- Well, I like doing it.

I'm out on the street all day long.

Citywide.

I like baiting.

I like killing the whole nest, going back, and it being fine and done, you know?

- [Geoffrey ] You guys don't look like cold-blooded killers.

(Josie and Steve laughing) - You know, it's- - Only eight hours a day.

(everyone laughing) (upbeat music fading out)