A stealthy, non-verbal battle for space occurs every day on the subway trains of New York City.

Many men sit with their knees splayed far beyond their hips, claiming enough space for two and sometimes three people in a position colloquially known as "man spread."

"I'm seeing so many guys do this!" exclaimed Julio Dominguez, 34, a Yorkville medical technician who declines to emulate the practice.

Dominguez posits that the popular posture is an attempt to broadcast a misbegotten notion of urban masculinity that contradicts his own definition, which is "having good manners and being courteous."

"Men need space," countered Carl Roberts-King, 25, a photographer and dancer from Crown Heights who copped to monopolizing more than one seat.

"That's how men sit -- as opposed to women, who cross their legs," added Luis Tutz, 23, a dancer, videographer and engineer from Bushwick who pleaded, "I don't mean to tick anyone off. ... Honestly, when I see there's no room, I get up and let someone else sit."

But the practice indeed peeves many passengers, especially women who feel they shouldn't have to ask a man to please close his knees.

The spread of man spread in a transit system that handles 5.8 million people on an average weekday has prompted complaints on social media and the creation of blogs, often crowd-sourced, devoted to documenting privilege-proclaiming postures and to publicly shaming and ridiculing practitioners. (Men Taking Up Too Much Space on the Train, One Bro Two Seats, etc.)

Bustle.com writer Gabrielle Moss was sufficiently irked to behave as a "slouch and spreader" for a weekend on the MTA and document her experience. Few people dared to challenge her, she said, because "everyone who rides public transportation is afraid that everyone else who rides public transportation is insane."

Chivalry isn't just dead -- it's extinct, fumed Cordelia Fossett, 59, of Harlem. When she asks an offender, "Excuse me, could you please close your legs a little bit so I could have some room?" her request is complied with grudgingly, often with a sigh or shrug. "They really don't want to," make room for other passengers, she said.

No, they don't, confirmed David Givens, an anthropologist who heads up the Center for Nonverbal Studies in Spokane, Washington. Humans generally dislike being in close physical proximity with strangers, prompting some men to indulge in "guarding behavior" by extending their appendages "like a buffer" to claim extra space while simultaneously warding away others, Givens explained. (The land rush is worst in individualistic cultures; people in collectivist cultures, such as Japan, know how to finesse close quarters.)

If one guy adopts the posture, others follow because "humans are the most imitative primates on the planet," Givens noted.

Cell phones and portable music players also have roles in the scourge. Space hogs "wire themselves into their own little cocoon," and ignore the obvious, albeit non-verbal, clues from standing passengers who wish to sit, Givens said.

Abraham Adams, 28, an editor who lives in Red Hook, began his crowd-sourced documentation of men's space-hogging behaviors in "Men Taking Up 2 Much Space ..." after female friends brought the "masculine power dynamic" to his attention. "Being a responsible guy involves analyzing behaviors," that others find offensive and inconsiderate, he explained.

Adams received so many impassioned -- and furious -- responses from men ("thousands"), insisting they must sit legs akimbo to accommodate their delicate, yet cumbersome genitals, he wrote a "superpoem" excerpting their assertions, none of which can be excerpted here.

About that rationale: "Sitting with legs splayed apart is rude, inconsiderate and has no medical rationale, especially if done only during the 30 to 45 minutes of a subway ride," according to Dr. Marc Goldstein, Matthew P. Hardy Distinguished Professor of Reproductive Medicine and Urology at the Weill Cornell Medical College of Cornell University -- who should know.

Most women just resign themselves to standing.

"What can you do? I never ask anyone to move. I don't want to start a confrontation," said Harriet Hale, 48, a financial associate who commutes from Jamaica, Queens.

Freda Manning, 27, an HR coordinator from Crown Heights, would like to see the MTA "put some posters up on the train of a guy sitting like that with a slash through it," not unlike a "no smoking allowed" visual, to convey the idea that space-hogging is verboten.

Moss concluded much the same in her Bustle article, saying "we need a public shaming campaign undertaken by the transit system."

That is unlikely to happen, according to a spokesman for the MTA. But the practice is, technically, illegal, as the MTA's disorderly conduct statute prohibits passengers from occupying more than one seat when doing so interferes with the comfort of other passengers.

Violating the statute merits a $50 ticket, but the NYPD did not answer an email asking how many, if any, people had been cited for the offense.