In Nicholson Baker's 1994 lit-porn novel The Fermata, his protagonist, a shy, would-be writer called Arno Strine, discovers he has the ability to freeze (or "drop") time. He uses this new-found power, as many a young fellow might, to perv on women without them knowing.
He explains the particular bonuses of his supernatural skill: "Each time I drop, I get another chance to love a chosen body as it really is: to see a woman's ass, for example, when its owner-operator is talking at a pay phone and thinking about other things than the fact that she has an ass, and her ass can therefore be completely itself."
Today, Strine would need no magical abilities to enjoy unadulterated ass in its natural state, though its "owner-operator" is more likely to be pointing her mobile at a mirror than talking at a pay phone. He would only have to follow the Instagram accounts of Kim Kardashian, whose butt cheeks caused the internet to spasm to a halt when she photographed them ballooning from beneath a white swimsuit in October 2013 (the bonus side-boob went more or less unreported), or Jen Selter, a woman who's ample posterior has earned her the sobriquet "the queen of the butt-selfie" (or "belfie") and a profile in Vanity Fair.
Bums are big right now, in all senses of the word. The waifs of the Nineties and Noughties have been crushed beneath a new idealised female form, a version of the "True Amazon" depicted by the cartoonist Robert Crumb in 2000, with a "strong back", "powerful, well-developed legs" and a "large muscular bottom, engine of the power centre" (and, as he excitedly notes in the drawing's subtitle: "This is not a fantasy, they dwell among us!").
Celebrities are bending over backwards – or rather, forwards – to display their wares, from renowned big-bottomed girls such as Nicki Minaj and Rihanna to women usually known for other assets, like Kelly Brook (breasts) and Lady Gaga (lobster telephone hats). Of course, as with any phenomenon in popular culture, from EDM to cronuts, it's possible to put forward an argument that the mega-butt's ascendency marks either the dawning of a golden age of enlightenment or End Times.
Either women are waking up to the opportunity that they're sitting on and are grabbing their assets with both hands, determining how they want to look, how they want to be seen, and reaping the benefits all for themselves; or they are little more than the Wagyu beef of the entertainment world, pumping their rumps up to prize-winning proportions, only to be sexually objectified by the patriarchy like never before.
But before all that heavy stuff, let's step back for a second, and think about the meaning of bums. In his seminal 1967 book The Naked Ape – and where would cod socio-anthropological pieces like this one be without it – the zoologist Desmond Morris posits the likelihood of an earlier evolutionary stage of sexual intercourse, when "we must have been using the rear approach". As in, doing it doggy style. To indicate that she was up for it, "the female signalled sexually to the male from behind with a pair of fleshy, hemispherical buttocks (not, incidentally found elsewhere amongst the primates) and a pair of bright red genital lips, or labia."
Morris suggests, albeit gently, that in order to shift the interest round to the front, thereby making sex more personal and men more likely to stick around, women had to develop "a duplicate set of buttocks and labia on their chests and mouth respectively."
While you're enjoying that mental image, think also what the implications might be of the fact that women today are shifting the emphasis back onto butts. Are we using enlarged arses to display a renewed interest in "coitus a tergo" (literally, "sex from behind"), because we don't care about feelings so much any more? Because we no longer need the emotional commitment from men that would ensure the survival of our progeny? Or because the success of sexual liberation means women get to behave a bit more sluttily? A bit more like, you know, men?
The counter argument, of course, is that women are leaning more and more towards meeting a male fantasy of sexual fulfillment in which female needs are entirely subsumed beneath their mate's. Certainly, there's nothing particularly enlightened about the lengths that some women are going to in order to beef up their behinds: a popular story on the website howtomakeyourbuttbigger.org, which launched last November – and shows a particular enthusiasm for a cream called Revitol – suggests rubbing a mixture of used coffee grounds and egg whites onto your rear before swaddling the whole thing in cling film, three times a week (although would-be users are warned "it can be quite itchy").
And there are the inevitable cosmetic surgery stats: according to figures released by the American Society of Plastic Surgeons, there were almost twice as many buttock-lift procedures carried out in the US last year compared to 2000, while 942 buttock implant operations took place in 2013 (no data was recorded for 2000). There are also plenty of enhanced underwear options for those not willing to go under the knife: US firm Bubbles Bodywear offers a winningly-named "Foxy Fanny Silicone Padded Panty Collection" and something called "Double-O Butt Lifters".
The padded bum phenomenon, at least, is not new. There are historical mentions of a "cul de Paris", a butt pad to be worn under a dress, that date back as far as 1725. "Women have often tried to draw men's attention to their rears, whether by swaying ostentatiously while walking, or by artificial padding for fashionable emphasis, as though their entire beauty depended on the attractiveness of their bottoms," writes Hans-Jürgen Döpp, in his book In Praise of the Backside (in which, yes, there are a lot of pictures).
"In the history of fashion, periods of slimness alternate with periods of voluptuousness. The cult of the callipygian [which means "having well-shaped buttocks", and if you learn just one thing from this piece let it be that] is always found in those periods where rounded, curvaceous, voluptuous women embody the ideal of beauty."
Kim Kardashian's infamous bum selfie
Those periods, and also those cultures: while larger bottoms might be coming into fashion in the West, other continents have been down with big bums for a while now. For centuries, the Khoisan people of Southern Africa have prized the beauty of women with a high degree of steatopygia, a genetic trait of pronounced fat accumulation around the buttocks (and if you learn two things from this piece, let that be the other). In Brazil, where G-string swimwear is practically mandatory, there is an annual Miss Bumbum competition to find the country's most formidable arse-cheeks – it was won last year by Dai Macedo, a 25-year-old model with a rear measuring 42 inches around.
In fact, argues Döpp, the worship of the bottom is not so much a national quirk as a fundamental psychological need: "The bottom is a place where instinctive drives and their sublimation can be localised, so that it could be said to represent the cradle of our culture."
Nowhere is the cradle of our culture more soundly represented in the 21st century than on the internet, and in the wake of Jen Selter, whose pictures of her ampersand of a butt have earned her 3.5 million followers on Instagram, a whole new raft of taut-cheeked young women are now making their bifurcated mark.
The likes of Canada's Caitlin Rice and North Carolina's Laura Gordon regularly post "belfies" to their 300,000 and 400,000 Instagram followers respectively, while taking a break from the many thousands of squats they've had to do to achieve their mathematically perfect curves. With Selter and her acolytes there's an assertion that this is a fitness phenomenon, that they are celebrating a healthy body and lifestyle, and that viewers can look at their pages and feel inspired. But if they think for one second that the first thing male fans are reaching for after clicking on their feeds is a celery stick they are sorely mistaken.
And really there, if you'll excuse the literal implications of the expression, is the rub.
Once upon a time, the arse was an extra – a perk accompanying another less-objectifying talent. Beyoncé has a 3.6-octave range and a 24-carat derrière. Jennifer Lopez, who is considered to be the godmother of the current butt fixation, can sing, dance, act and sit very comfortably in economy (remember: she's still Jenny from the block). Things started to slip south with Kim Kardashian – model? TV star? Shopkeeper? Who can say? – and nowadays women are becoming famous for their arses.
And that's it. No ifs, just butts.
Often the likes of Selter, Rice and Gordon don't even bother showing their faces. Selter's tuchus is more likely to get stopped in the street than she is. Their bums are their projects, their pets, their livelihoods. Their moneymakers have become exactly that. These women have turned into, as Strine describes in The Fermata, the "owner-operators" of their arses. What's the natural progression from this state? Instagram feeds run by bottoms themselves, no woman required? Perhaps mega-butts will tire of their overbearing owner-operators: maybe they'll unionise, revolt, go freelance. Strine's dream of a time when "the ass can be completely itself" might be closer than he thought.