Bears are not the only creatures that shit in the woods. In Wild, for which she has been nominated as best actress, Reese Witherspoon confronts her own waste product during the early stages of her long walk along the Pacific Crest Trail, which runs from California to Canada. She's playing Cheryl Strayed, who wrote a best-selling book about her cathartic walk along the trail.

It's a sign of the film's urgent desire for credibility that it shows us her character's excrement. Poo is one of the last great taboos on screen, for good reason. We go to movies to get away from things like that. But the wilderness brooks no escape, not even from bodily functions. That's the point. Every movie about going into the wilderness is about finding oneself by losing oneself. And 99 per cent of them are about himself. Men go into the wild, women do not – until now.

"When it comes to women on screen," wrote Charlotte Alter in a recent issue of Time, "the lone frontier is the last frontier. It's no big deal to see women play presidents villains, baseball players, psychopaths, superheroes, math geniuses, or emotionally stunted losers. We've even had a female Bob Dylan. But a woman, alone, in the wilderness, for an entire movie? Not until now."

She has a point, even if she stretches it by claiming that Wild is the first big movie in which a woman confronts the great solitude. Tracks, based on Robyn Davidson's celebrated memoir, got there a year earlier, and with greater solitude. The three Aboriginal girls from Rabbit-Proof Fence did it in 2002, although that wasn't so much a confrontation with solitude as an escape narrative.

Tracks and Wild have as many differences as similarities. Strayed took to the track to run away from herself and arrest a four-year binge of sex and drugs after the death of her mother. She is walking to obliterate herself, to disappear into the landscape and perhaps purify herself in the cold of the high Sierra. In fact, all the usual things that men do in wilderness movies, at least American ones. Blame Henry David Thoreau and On Walden Pond for that strain of romanticism in American life.

In Australia, our narratives are different. People become stranded in the desert or get murdered by serial killers, but they don't choose to go out there alone, for an extended period of aloneness. Yet that is exactly what Davidson set out to do in 1977 with her four camels and her beloved dog Diggity. John Curran's movie, with the fabulously adaptable Mia Wasikowska as Davidson, has a great sense of the strangeness of that quest. Witherspoon's journey is much more psychologised, full of regretful flashbacks. In Tracks, we have to guess why Davidson wants to walk 2700 kilometres across the desert. We don't find out until the last third of the movie that her mother hung herself. Clearly, this had an impact, but the movie never labours it.

When Wasikowska finally breaks down in the arms of the American photographer Rick Smolan (Adam Driver), after she has almost perished in the desert, she says: 'I'm so alone'. She has had to shoot Diggity after the dog ate poison, so her next line, "I miss her so much" sounds like she's referring to the dog, rather than her mother.

My point is that Davidson's journey is not really an escape narrative: she wants to embrace the desert and be educated by it, to learn from the Aborigines she meets and the animals that she likes more than humans. Witherspoon's quest as Strayed starts in a psychological wilderness of her own making, and travels back to mental health. Davidson's goes the other way, to the edge of madness. She wants to see if she can live without others, particularly men.

Nearly all the men in Tracks are creeps. Funnily enough, both Tracks and Wild were directed by men. Jean-Marc Vallee (whose last movie was Dallas Buyers Club) was a director for hire on Wild. Witherspoon bought the rights and developed the script with Nick Hornby adapting the book.

It's harder to find women-in-the-wilderness movies directed by women – although Meek's Cutoff (2010) is one powerful example. Kelly Reichardt directed Michelle Williams as a member of a wagon party trying to cross the Oregon desert in 1845. Their Indian-hating guide (Bruce Greenwood) gets them lost, so she forces the others to trust a captured Indian (Rod Rondeaux) to lead them to safety.

Sound familiar? Same thing happens to Wasikowska in Tracks, when she has to team up with an Aboriginal elder, Mr Eddy (Roly Mintuma), to guide her across the harshest part of the desert, avoiding the sacred sights that women are not allowed to see. In 1971, David Gulpilil was the saviour/savage in Nic Roeg's highly influential film Walkabout, saving 16-year-old Jenny Agutter and her little brother, played by the director's own son, Lucien, but not himself.

All of these stories are at least partly derived from the story of the Garden of Eden. The one thing you can guarantee: at some point, there will be a snake. Both Tracks and Wild are about women trying to live apart from men, at least for a time. In both movies, they fail, but each emerges stronger from the ordeal. Each learns what she is capable of. We can expect more of these movies. A trend has begun.