In her bestselling Animorphs series, Katherine Applegate introduced teens with the ability to morph into any animal they touch. She offers a very different take on an animal story in The One and Only Ivan (Harper). The novel is based on a real-life silverback gorilla born in Africa that lived in a glass box for 27 years as an attraction in a circus-themed mall in Tacoma, Wash., before being transferred to Zoo Atlanta, where he still resides. Ivan’s story made a splash in the media and caught the attention of Applegate, who talks about how her novel came to be.

How did you first heard of Ivan’s plight?

I read a piece about Ivan in the New York Times, I’d say almost 20 years ago—back in the days when newspapers were actually made out of paper. It was before Ivan was released to Zoo Atlanta, which I believe was in 1994. So I cut out the article and tossed it in a box with a million other story ideas.

What was it about Ivan’s story that grabbed you?

I found his story so heartbreaking, and I followed it in the media over the next few years, waiting to see what happened. Ivan had been isolated in the mall for 27 whole years, and people finally began to understand that animals in captivity require the presence of others of their kind. But Ivan was not instantly released. There was a long litigious battle and eventually there was a passionate outcry from people, including many little kids who wrote impassioned letters. He was eventually acquired by Zoo Atlanta, which has the largest population of gorillas in this country.

At what point did you decide to turn your interest in Ivan into a novel?

It was maybe five years ago. I had started writing two middle-grade novels for Anne Hoppe, my editor at HarperCollins. But I kept getting distracted by Ivan’s story—it continued to haunt me. And Anne, being wonderfully patient, said, “Why don’t you just go ahead and do the Ivan book first?” So I did.

Did the book fall into place quickly?

Well, it took a while for me to figure out how to do it. I had to decide whether or not to write a journalistic piece, or an animal fantasy, where I’d have to get more anthropomorphic. In the end, I liked the idea of giving Ivan himself a story to tell, using his actual story as a departure point. I thought that was the best approach to take to invent a story for him.

Ivan’s voice has a poetic, spare quality. Did you find it easy to slip into his voice?

Once I knew where I was going with the book, his voice did come quite easily. Gorillas may seem terrifying because of their bodies, but they are really magnificent and very gentle. I wanted his voice to convey that calm dignity that I associate with gorillas. And I tend to write short, brief snippets—I lean toward the chamber music end as opposed to the symphony end of things. I realized that Ivan’s voice was a good match for me. He is a gorilla of few words.

Speaking of words, at one point in the novel, Ivan says that sometimes he forgets what he is and wonders if he’s a human or a gorilla, and observes that, though humans have more words than they truly need, “still, they have no word for what I am.” Would you say Ivan’s struggle with his identity is a major theme of the novel?

Absolutely. In fact, I think if you’re looking for one sentence that distills the book, that sentence does it perfectly. I hate to witness animals in captivity—or see circus elephants paraded down the streets. When animals are caged, it’s a loss of what they are. Of course zoos are not a perfect solution, but it’s what we’ve come up with. Fortunately, the zoo where Ivan ended up is a wonderful place—but even that isn’t perfect.

Did you visit Zoo Atlanta in the process of writing The One and Only Ivan?

I did actually. It was a rainy, cold day, and Ivan is notoriously averse to cold weather. He was born in Africa, after all. I stood with my daughter in the rain, hoping against hope that Ivan would come out and we could catch sight of him. A lot of other gorillas did, but Ivan never did. But it was somewhat gratifying to think that finally, after all those years when he couldn’t, he can now exercise a bit of control over his life. That was kind of nice.

What do you hope kids take away from Ivan’s story?

I hope they realize that it takes a lot of courage to stay true to yourself in grim, lonely circumstances, and will take heart that Ivan found a place where he belongs. The attitude toward captive animals has changed over the years in a gratifying way, but it’s been a slow change, and some animals’ situations break my heart. At the end of the day, I’d love to see children stop begging their parents to go to the circus. That’s what would make me most happy.

Do you view this novel as a departure for you, in terms of subject and writing style?

I’d say it parallels some of the feeling of Animorphs. In those books, I got to explore what it was like to feel like an animal, so on that level it’s channeling the same kind of thing. Stylistically, this novel is more similar to Home of the Brave [Feiwel and Friends, 2007], which I wrote from the point of view of a refugee of Sudan.

Are there more animal books in your future?

Absolutely! I’m now writing a novel from a dog’s point of view. It’s one of the novels I was working on when I digressed to Ivan. It’s another middle-grade animal fantasy.

You seem to be quite at home in that genre.

Yes, I love those books. I grew up reading and rereading Charlotte’s Web and anything by Jean Craighead George. I loved any book that had to do with animals. As a writer, maybe I’ve finally found the place I’m happiest. It only took me 20 years. Maybe I’m a slow learner?

The One and Only Ivan by Katherine Applegate. Harper, $16.99 Jan. ISBN 978-0-06-1999225-4