It's Curious City, where we take your questions about Chicago and the region, and investigate, report.

Explore.

From WBEZ.

100 years ago, it was widely believed that in big cities like New York and Chicago, there was a rat for every person. Think about

that. Like, maybe there's a rat version of you somewhere listening to Rat Curious City, wearing

cute little rat headphones? Anyway, that one rat per person idea has been discredited. But people

are still trying to guess the number of rats in big cities, like 12-year-old Justin.

I read in a book, The Problem that New York had with rats.

So he wanted to know about his city.

How many rats are in Chicago? And why?

I'm Jesse Dukes, and when I saw Justin's question, I thought this is going to be fun.

See, as far as I was concerned, rats are no more scary than squirrels or seagulls.

And it's always amused me how they creep people out.

But after reporting Justin's question, I am a changed man.

Y'all, we gotta talk about our rat problem in Chicago.

They can spread nasty bacteria like e-coli and rare diseases

like plague, aka the black death. They can chew into homes and through cars doing tremendous

property damage. And in restaurants, well, we'll get to that. But first, let's start with why

we have any rats in Chicago. Maureen Murray is a biologist at the Lincoln Park Zoo's Urban Wildlife Center and an expert on Chicago's rats.

She says rats can eat just about anything, take advantage of small spaces, and because of all the food, and not too many predators.

They actually reproduce faster in urban areas than in rural areas.

A single female can have more than 80 baby rats in a single year, and she could have

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