Panbanisha wants coffee – a tall decaf Starbucks caramel macchiato, to be exact. Midway through a demonstration of her extensive vocabulary, obligingly pointing to the correct symbols on a complex board for "yogurt," "egg," and "hurt," she switches gears and points to the symbols for "candy" and "coffee" – her term for a caramel macchiato.

"You want coffee, Panbanisha?" asks William Fields, a senior researcher at Des Moines's Great Ape Trust – a question that Panbanisha responds to with an enthusiastic series of loud shrieks. A few more exchanges, and she's made sure he knows to get enough for the other six apes, to get "marshmallow" – her word for the foam on top – and to get the drinks now!

Panbanisha is a bonobo – one of the four great ape species, also sometimes called a pygmy chimpanzee, and one of the most humanlike. She is on the cutting edge of research that's revealing a surprising amount about how bonobos learn – and how similar to their human cousins they really are.

The exploration into one of the most fascinating dimensions of the animal kingdom is taking place in a new state-of-the-art research facility on the edge of this Midwestern city. Here, in a massive concrete-and-glass structure, scientists are watching how the bonobos interact as they live in conditions not unlike suburban America.

The primates, for instance, enjoy an enviable view of the lake and forest that surround the center, which they often get to explore when the weather cooperates. Inside, they have climbing towers and a splashing pool with a waterfall they can turn on themselves. When visitors come, the bonobos decide whether or not to let them into the special visiting room, where they can exchange food or other items from vending machines. They can watch videos – favorites include gorilla films and (does this sound familiar?) movies of themselves. They leaf through books and magazines. The bonobos seem to have everything but TiVo and a Toyota Camry in the driveway.

***

At the center of the research here is language. The work at the Great Ape Trust grew out of a project begun more than 20 years ago in which researchers tried to use symbols – called lexigrams – to communicate with bonobos in a new way. They wanted to avoid criticisms of past language research, such as the possibility that apes were just responding to nonverbal signals.

They had little success with Matata, an older bonobo born in the wild. But when she was away from the research station one day, scientists discovered that her young son, Kanzi, had learned a dozen of the lexigram symbols – like "banana," "peanuts," "bite," and "tickle" – without any actual instruction, simply by being nearby. Today, Kanzi knows more than 360 lexigrams and understands several thousand spoken words of English.

"The only organisms capable of learning language are babies," says Mr. Fields, who has been with the project almost since the beginning.

The mistake other research has made, he says, is trying to teach apes words the same way they would a second language – almost like a Berlitz class for animals. What's needed is to pick it up as a first language like humans do – by constant exposure to it at a young age, as a part of their everyday culture.

Most of the study has taken place at the Language Research Center at Georgia State University in Atlanta. Today, Kanzi and his sister, Panbanisha, along with Matata and four other bonobos, have moved to their new home at the Great Ape Trust here, where researchers hope the comfortable surroundings will help the primates develop and express themselves.

Their character and curiosity is definitely coming out. Kanzi, for instance, shows a particular liking for the Victoria's Secret catalogue. "Good Night, Gorilla" seems to be a favorite book of the whole clan. Panbanisha may be the next Julia Child: She recently watched a tape of herself making eggs and noodles in the kitchen, and, as Fields looked on, she pointed to various lexigrams to narrate what would happen next.

Kanzi loves to play with his ball and the other toys, which he lugs around in his backpack. He knows how to build a fire and works with primitive tools: He'll flake and sharpen stones and then use them to cut rope.

On this day, Panbanisha dutifully – and rapidly – points to the lexigrams that a researcher requests. But she devotes most of her attention to trying to get a screw out of the battery compartment of a talking toy dog with a pair of scissors. Nearby, Kanzi is busy threading beads on a string – not an easy task with his large fingers. But he's persistent and surprisingly adept.

"I went into this as a true skeptic," says Duane Rumbaugh, who's been researching apes and language for several decades. "I anticipated failure with apes." Instead, Dr. Rumbaugh has become a true believer that apes are capable of understanding language, not just responding to visual cues.

Researchers are able to capture all the bonobos' actions because of a phalanx of cameras at the center, one of its most important features. The research team – which includes Fields, Rumbaugh, and Sue Savage-Rumbaugh (lead scientist) – is doing more than just exploring the limits of ape communication and intelligence. It's trying to understand the role culture plays in their learning. "You can't have language without culture, or without choice and agency," Fields says.

***

Watching Panbanisha put on a halloween mask to scare visitors, or seeing Kanzi goad visitors into chasing each other, it's hard not to see them as part human. And the researchers clearly feel a bond that goes far beyond scientist and subject. "It's like your own child," says Fields, as he talks about the week when Nyota, one of the youngest bonobos, nearly died. Fields didn't sleep for seven days. "Nyota loves Spiderman and Harry Potter, he didn't like Catwoman – he's really just a normal little boy."

Kanzi may be the media superstar of the group, famous from articles and photos, but Fields and Dr. Rumbaugh say Panbanisha is the analytical genius: She may understand as many as 6,000 spoken words. "Unlike Kanzi, she doesn't care about showing off what she knows," Fields says.

She's also empathetic. Fields remembers the day in Georgia when an armless orangutan whom Panbanisha felt protective of hadn't come inside, and Panbanisha got Fields's attention and reminded him to take milk to the primate – now. Another time, when Fields locked himself in a room, he sent her to tell Savage-Rumbaugh to bring a key. "These are anecdotes," says Fields. "But with cameras running all the time, you can start to get the data."

In the end, he and the other researchers will shed light not just on apes as our closest living relative, but on humans, too. "I think we can define culture in the kind of way anthropologists have been trying to do for a long time," says Fields.

And they hope that the discoveries about just how intelligent – and human – the bonobos and other apes are may help spur more efforts to save the threatened species in the wild, and offer insights into how best to do it.