Just as her fourth novel, Ape House, hit bookshelves last month, Sara Gruen's 2006 novel, Water for Elephants, was notching up its 98th week on The New York Times' best-seller list.
With three million copies in print in 44 countries and a movie version starring Robert Pattinson and Reese Witherspoon being released in April, Water for Elephants now ranks as one of the most-loved novels of the past decade. But even now, the Canadian-born, US-based novelist and mother of three can't tell you why it is people respond to it so powerfully. 'If I knew, I'd do it every time,' she quips.
Ape House, with its focus on bonobo ape culture, is a world away from the 1930s-era circus setting Gruen wrote about so tellingly in Water for Elephants. She was already well into another novel when, while on tour to promote Water for Elephants, she took her mother's advice, and looked at the website of The Great Ape Trust, in Iowa. The research facility is renowned for its investigation into great ape language.
'I've been interested in great apes and human discourse from 1980 when I first heard about Koko the gorilla using a version of American sign language, but I hadn't heard about bonobos before so I was really fascinated. This was something that I just knew I wanted to write about. But I knew I couldn't write about it authentically unless I got access to the apes.'
She also knew that access wasn't guaranteed, and that she was among literally thousands of people, including some of the world's most eminent scientists, who've been lining up for years to meet the trust's resident bonobos, who communicate with humans using lexigrams. 'The scientists can invite you, but it doesn't mean that you're going to get in. The apes have to invite you, because it's their home. These are not zoo animals on display,' she says.
Gruen immediately formed a bond with bonobo matriarch Panbanisha. 'I was just blown away.' Panbanisha typed out the words 'babies wash in bubbles' when Gruen held up a photo of her own children in a bubble bath. 'It's one thing to read about this and see videos and read studies. It's entirely another thing to be sitting in the forest having a tea party with an ape, who segues from asking you what you had for breakfast to requesting the return of the Easter Bunny.'
First thought to be a subspecies of the common chimpanzee, bonobos were known as pygmy chimpanzees until 1929, Gruen says. 'But their culture is very, very different from chimpanzees. They don't have the ritualised violence, the organised warfare. There's no infanticide. They don't seem to have the social problems that chimpanzees and humans do.'
It's these peaceful characteristics, along with the bonobos' unique linguistic skills, that inform Ape House, which is partly a sly satire on human behaviour. It unfolds when journalist John Thigpen visits the Great Ape Language Laboratory to interview its key researcher, Isobel Duncan, and the six bonobos that live there. After a bomb is thrown into the lab, nearly killing Isabel and 'liberating' the apes, Thigpen's human-interest story turns into a national news story that he is forced to share with a rival. Then, when the apes go missing, secretly sold to an anonymous buyer, he is sidelined completely. But when the bonobos later turn up as 'stars' of a reality television show called Ape House and owned by a local porn king, Thigpen risks all, including his marriage, to rescue them and discover who had traded them to the TV show's unscrupulous proprietor.
For Gruen, who caused a stir in publishing circles when she signed a US$5 million two-book deal with Spiegel and Grau in 2007, success has been hard won.
She'd long had ambitions to be an author, but it wasn't until she lost her job as a technical writer that she wrote her first novel, Riding Lessons, and, despite its modest success, struggled to find a publisher for Water for Elephants.
Finally picked up by a small publishing house, it became a word-of-mouth best-seller, championed by independent bookshops.
'When I learned that it had hit number one [in the best-seller list], my husband went and got a bottle of champagne. We drank it as I was folding everyone's laundry,' she says.
Even now, despite her success, she still does 'a lot of laundry. We've tried hard not to change much'.
That success has brought more pressure than freedom, but she says: 'I'm very lucky that I can now actually follow my passions.'
As to the impact of Ape House, now climbing best-seller lists, she says: 'I'm not sure that I've really taken it in yet. I feel like I've caught lightning in a bottle. I don't know why it happened; I don't know how it happened. I'm really glad it happened. I just hope I can make some kind of difference in the future for bonobos. I hope that's possible.
'I don't know if it is, but as Gandhi once said, we can judge societies by the way they treat animals.'