This is Fresh Air. I'm David B. and Koolie, Professor of Television Studies at Rowan University in New Jersey, Infra Terry Gross.

When birds flock near airports and get sucked into jet engines, or when deer run onto highways and cause car accidents,

or when bears wander into towns and campsites where food remains are plentiful, they cause problems for us.

In all these cases, of course, the animals are just following their instincts. They fly, they run, they forage for food, they seek mates.

But when they interfere with our way of life and break our rules, some humans, often people in ranger hats and uniforms and lab coats, have to try to figure out what to do about it.

Our guest, Science writer Mary Roach, has a book now out in paperback about the many conflicts between humans and animals, including bears, elephants, monkeys and mice, and how different societies try to deal with them.

Roach has a way of handling sometimes uncomfortable subjects with wisdom and wit. Among her six best-selling books are Stiff, the curious lives of human cadavers, and Gulp,

Adventures on the Elementary Canal, a book about what happens in the human digestive system from top to bottom.

Roach talked with Dave Davies last year when her book called Fuzz, when Nature breaks the law, first was published.

Mary Roach, welcome back to Fresh Air.

Oh, thank you so much.

You know, anybody who's owned a cat is aware of this conflict between natural instincts and rules we try to impose. What got you interested in this question?

Well, I wish I had a tidy origin story, but what happened was I was flailing around looking for a book topic as happens every few years, and I got interested in the forensics of wildlife crime, not when the animals are the quote-unquote criminals, but when the animals are the victim.

So I was, I got interested in the forensics of animal trafficking, specifically a woman who published a guide for wildlife law enforcement on how to distinguish real versus fake tiger penis that is dried, which is sold medicinally.

And I thought that's kind of a bizarre expertise, and I spoke to her, and I kind of got interested in wildlife forensics.

Unfortunately, I wasn't allowed to tag along on any open cases, and I always like to kind of be on the scene in my books. And so that was a dead end.

But as often happens, it morphed into a related topic, which I kind of turned it inside out.

What if the animals were the perpetrators of these crimes, and I'm using crimes loosely, they're obviously just animals, as you said, following their instinct.

But I got interested in this field, human wildlife conflict, which I had never heard of, and anytime I hear about a pocket of science that I've never heard of before, I get kind of excited.

And I think maybe this is a book, and lo and behold, it became a book.

And you traveled many continents, researching it. And I got to say, it is a fun read. You have a lovely touch with this stuff.

You know, you begin by telling us of a case in the 17th century of some towns in Italy, who undertook legal action against caterpillars that were munching on crops and gardens, actually issuing the summons for the caterpillars to show up and appear in court.

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