American author Elif Batuman tweeted recently: "Every day I wake consumed by rage because Wolf Hall isn't about wolves." She can keep channelling her anger elsewhere because Sarah Hall's new novel, The Wolf Border, is about wolves.

Ghostlike, yellow eyes glimmering, lean, grey flanks rippling, they lope and streak through the heather in the pages of this absorbing novel so thrillingly and so metaphorically that you could say that Hall has created the ultimate Wolf Hall.

Her sexually predatory heroine, Rachel Caine, is a zoologist, a lone wolf from a "riven" family, who has spent a decade in the company of wolves, monitoring them on a rugged Idaho reservation, which Hall visited when she lived in the States, in her twenties, following her brief first marriage.

Pregnant after a one-night stand, Rachel returns to her native Lake District - Cumbria-born-and-bred 41-year-old Hall's literary and personal heartland - to oversee the swaggering Earl of Annerdale's desire to make his very own Jurassic Park on the country's largest private estate by rewilding his land and reintroducing the grey wolf into England, "the prerogative of wealth and wilful eccentricity". (Shades of the controversial plans of multimillionaire Paul Lister, heir to the MFI fortune, to establish a "wilderness reserve" on his 23,000-acre Alladale estate in Sutherland.)

So far, so George Monbiot, whose 2013 book Feral led to a national debate over the merits of restoring the country to a wilder state. (The last wolf was reportedly killed in Scotland in 1680.) But Hall's novel, her fifth and, I think, her best, also has the distinction of being one of the first works of fiction set against the backdrop of the Scottish referendum - in her universe the nationalists triumph. Thus our parcel of the island is released to the wild and, therefore, reclamation by the people. Dances with wolves indeed.

Hall's evocative title is based on the Finnish word, Susiraja, "literally 'wolf border': the boundary between the capital region and the rest of the country. The name suggests that everything outside the border is wilderness," she writes.

What came first, the desire to write about big politics, wolves or the whole issue of rewilding? The award-winning, twice Booker-nominated novelist is speaking from her home in Norwich, where she is nursing her seven-month-old daughter, Loy, her first child with her doctor partner, James. Talking at breathtaking speed, Hall replies: "It's funny isn't it? You think back and you ask yourself why you became so interested in wolves. I think it was because when I was very small, growing up in a little hamlet, near Shap, we would go to Lowther Wildlife Park for birthday parties. Now closed, it was only three miles from my parents' house."

In the opening chapter of The Wolf Border, Rachel dreams vividly of a childhood visit to Setterah Keep, "a ruined Victorian menagerie in the woods in the Lowther Valley" where she first encounters a wolf, a perfectly made creature: "long legs, sheer chest, dressed for coldness in wraps of grey fur... A dog before dogs were invented. The god of all dogs." This is typical of the way Hall writes semi-autobiographically and with tenderness of wolves, just as she writes viscerally about pregnancy, motherhood, babies and the sex and violence of the natural world.

Hall recalls: "The wolf was the most exotic creature they had in the park. So, yes, Rachel's opening dream is very much based on Lowther Wildlife Park and seeing a wolf for the first time. When you are a kid, a wolf is an amazing sight, so sumptuous. I sort of knew these were splendid creatures, that I was not going to find them outside roaming around. It was like a dog, but not a dog. It was incredible, a god! We all have our preferences - some people go for birds - but for me, there's just something about the wolf, the design of it is really aesthetically pleasing.

"No, I don't think they had Little Red Riding Hood connotations for me, although wolves do only exist now in most people's minds in that mythical, fairytale way. So I've had to engage in the novel with that Gothic notion that wolves are going to eat children.

"That pre-verbal memory just lodged in my mind. Having lived in North America, obviously they have wolves there, I knew about their reintroduction projects. In any case, if you come from the countryside as I do, then you'll always be interested in debates about it and the national parks. I'm very aware of modern countryside issues, such as rewilding, how as science progresses we begin to understand that a healthy ecosystem is multiform. Yet we have no big predators left so I'm interested in all of those questions because the Lake District is a very cultivated wilderness."

Additionally, after living in Wales and Ireland and Scotland - Hall read English and History of Art at Aberystwyth University and gained her MA in creative writing at St Andrews University - non-English politics have always fascinated her. "I was very, very interested by the referendum debate and how close the vote was. It's not for me to say because I'm not Scottish and I don't live in Scotland anymore but I'm always very, very excited when a country says it can do better politically and socially in terms of equality.

"It's not so much that I am pro-independence but that I'm interested in what better things can be achieved. That conversation is lacking in England and, if you come from the edges of England, you have more in common with Scotland. If you come from Cumbria, you look to Edinburgh and Glasgow because you feel much closer to Scotland. I find the whole debate thrilling. I can't believe how, whenever I go back to Scotland to stay with friends and my godmother, conversations always revert to politics. It's a complicated issue; Scotland faces massive challenges economically, the way England and Wales do.

"But there are things that Scotland possesses, like the Highlands and the wildernesses, and there is such an unequal distribution of land among the wealthy, worse than anywhere else in Europe. It's exciting that things can be done regarding land reform. Wolf-watching, too! Romania makes a lot of money out of ecotourism, for instance. I'm really interested in all these new revenue ecostreams that Scotland could possibly lead in. But, hey, I'm not a politician!"

Hall finished writing her novel before the referendum. "The polls were very, very close and I sort of thought the Yes vote would have it. I finished the final copy-editing in mid-August - my daughter was born a week later. I knew the book would either be predictive or counter-factual. In the end it's counter-factual," she laughs. "But I'd actually finished the book before I got pregnant. My second biggest worry, apart from the wolves and the politics, was whether I'd got the motherhood stuff right, because I hadn't been through it."

As well as all her pregnancy research, Hall did "a phenomenal amount" of wolf research. "For about two years I became the biggest wolf bore at the dinner table ever! 'Did you know that they can swim eight miles, everyone?' My friends would be groaning, 'Oh God!' It was like people who went to Oxford and Cambridge, how quickly are you going to mention that fact? The answer is in about 20 seconds! I'd love to be a wolf biologist. I'm quite feral anyway."

Somehow, Hall has made big politics and wolves sexy - she is, in any case, a very sexy writer as she has proved in novels such as The Electric Michelangelo, which to her surprise is adored in France, and her brilliant short story collection, The Beautiful Indifference. "Oh, thank you!" she exclaims. "Wolves are sexy. They are muscled and glossy like athletes. It's about inter-species attraction, I suppose. I don't mean bestiality, but I do get a strange thrill out of looking at them. And, yes, wolves are not, as Angela Carter has it, hairy on the inside, unlike some men."

As for writing about sex, she enjoys the challenge. "I don't know why so many novelists avoid it. Some think it's too difficult, too risky. But it's a great human transaction. It really does do some extreme things to people. It's also a mundane, habitual thing. You can't not write about it."

She'll be writing about it again - as she will about Cumbria. "I am not done with either," she confesses. She's almost finished a second collection of short stories - in 2013 she won the BBC's £15,000 prize for her wonderful short story, Mrs Fox - and reckons that writing short stories has made her a better novelist.

What about motherhood? Will that make her a better novelist? "Motherhood is such a fugue state," she replies. "I really don't know but I can't wait to find out. I hope it'll make me more organised. For now, though, it's certainly made me much more messy."

The Wolf Border by Sarah Hall is published by Faber & Faber, £17.99