LOS ANGELES - Well, here you are in 2008, standing erect on two feet, arms free, fingers and opposable thumbs ready to reach out and grasp whatever it is you want.

Yes, you, proud member of the human race, the dominant species on Earth.

And if Dorothy Hearst is right, you owe it all to your dog.

Hearst is no scientist; she's a fiction writer. But her debut fantasy novel,

Promise of the Wolves

, draws on research that suggests humans and canines (first wolves, then dogs) have a long, shared history.

"The book is based quite a bit on the theory of co-evolution," Hearst said, "which is the idea that wolves and later dogs are what made us the dominant species on the planet - that we evolved because of them, and they evolved because of us."

Like much of science these days, that theory is contentious. But it's been widely reported and discussed in the last couple of years, with some researchers asserting that humans grew stronger by taming wolves, then hunting with them.

In turn, wolves began to look less like themselves and more like dogs as selective breeding for certain characteristics also gave rise to changes in the animals' appearance.

In short, Hearst said: "We made dogs and dogs made us. Some of the genetic [research] is fairly controversial, but there is some evidence that wolves and humans have been together for 150,000 years - and other evidence that suggests it could have happened before we were even fully human."

Promise of the Wolves

isn't exactly a summer best-seller, but it's doing well; it was recently listed at 32,860 on amazon.com's sales list and had garnered 60 customer reviews.

Inspired by science, the novel also is fueled by fantasy. Set 14,000 years ago, it concerns a she-wolf called Kaala, whose desire to hunt with humans is scorned by other wolves.

And, yes, these animals have the power to communicate, a la the rabbits in Richard Adams' classic

Watership Down

, which Hearst, who lives in Berkeley, Calif., acknowledges as a significant influence.

Now 42, she grew up reading fantasy and science fiction, including genre giants such as Anne McCaffrey, Arthur C. Clarke, Isaac Asimov and Ray Bradbury. She was raised in the Bay Area of San Francisco; when college loomed, she was torn between "going into science or the arts."

"I have to admit the reason I went into the arts was that I was a really good student in English and a fair student in science. It has worked out well, because I love science at the conceptual level, but I get to a certain point where if there are unknowns, I get very frustrated.

"And what's fun about being a fiction writer based in science is that when people don't know the answers, you get to make them up!"

Despite her influences,

Promise of the Wolves

is very much her own. Readers looking for Adams' influence can find it, but the tone of Hearst's novel is a bit tougher.

She doesn't lack for literary ambition - this novel is the first in a trilogy that publisher Simon & Schuster already is referring to as "The Wolf Chronicles."

Hearst doesn't know how long the writing will take, but she is now hard at work on the second book, and her face lights up as she discusses the task at hand.

While for some writers the act of creation can be drudgery, or filled with pain, Hearst clearly relishes it. One reason might be the spirit of adventure she indulges as she works.

She admits she's not the most thorough when it comes to premeditation and outlines and such.

"I don't know that I always have much choice; my characters sometimes do things I don't expect. I know where I'm going to end up, but I'm not entirely sure about how I'm getting there."

It's been said more than once that a writer unsurprised with his or her own work won't surprise readers, either. Hearst seems determined to enjoy the element of discovery.

And her subject matter should help keep readers coming back. Canines have nosed their way strongly into the literary world lately. Recent fiction includes Toby Barlow's

Sharp Teeth

, and, of course, there's former Inquirer columnist John Grogan's mega-selling memoir

Marley & Me

. (The movie version, starring Owen Wilson and Jennifer Aniston, is scheduled for release on Christmas Day.)

What is this fascination, anyway? What is it about these slobbering pooches that captures our hearts and minds?

"It's one of the questions that led me to write the book," Hearst said. "There is no other animal we feel this way about. We love dogs more than anything else, and they're really the only animal we think of as not outside of ourselves.

"We think of them as family, as our children. I really think it is something that goes far back into our past - that the two species have been linked for a very long time."