Faculty members and administrators are well aware of the situation. Stephen M. Farmer, North Carolina’s director of admissions, said that the university has a high female presence in part because it does not have an engineering school, which at most schools tend to be heavily male. Also, he said, more young men than women in the state opt to enter the military or the work force directly out of high school.
And the university feels obligated to admit the most qualified applicants, regardless of gender, Mr. Farmer said. “I wouldn’t want any young woman here to think that there’s somebody we’d rather have here than her,” he said.

The phenomenon has also been an area of academic inquiry, formally and informally. “On college campuses where there are far more women than men, men have all the power to control the intensity of sexual and romantic relationships,” Kathleen A. Bogle, a sociologist at La Salle University in Philadelphia, wrote in an e-mail message. Her book, “Hooking Up: Sex, Dating, and Relationships on Campus,” was published in 2008.

“Women do not want to get left out in the cold, so they are competing for men on men’s terms,” she wrote. “This results in more casual hook-up encounters that do not end up leading to more serious romantic relationships. Since college women say they generally want ‘something more’ than just a casual hook-up, women end up losing out.”

W. Keith Campbell, a psychology professor at the University of Georgia, which is 57 percent female, put it this way: “When men have the social power, they create a man’s ideal of relationships,” he said. Translation: more partners, more sex. Commitment? A good first step would be his returning a woman’s Facebook message.

Women on gender-imbalanced campuses are paying a social price for success and, to a degree, are being victimized by men precisely because they have outperformed them, Professor Campbell said. In this way, some colleges mirror retirement communities, where women often find that the reward for outliving their husbands is competing with other widows for the attentions of the few surviving bachelors.

“If a guy is not getting what he wants, he can quickly and abruptly go to the next one, because there are so many of us,” said Katie Deray, a senior at the University of Georgia, who said that it is common to see six provocatively clad women hovering around one or two guys at a party or a bar.

Since that is not her style, Ms. Deray said, she has still not had a long-term relationship in college. As a fashion merchandising major, she said, she can only hope the odds improve when she graduates and moves to New York.

At colleges in big cities, women do have more options. “By my sophomore year, I just had the feeling that there is nobody in this school that I could date,” said Ashley Crisostomo, a senior at Fordham University in New York, which is 55 percent female. She has tended to date older professionals in the city.

But in a classic college town, the social life is usually limited to fraternity parties, local bars or coffeehouses. And college men — not usually known for their debonair ways — can be particularly unmannerly when the numbers are in their favor.

“A lot of guys know that they can go out and put minimal effort into their appearance and not treat girls to drinks or flatter them, and girls will still flirt with them,” said Felicite Fallon, a senior at Florida State University, which is 56 percent female.

Several male students acknowledged that the math skewed pleasantly in their favor. “You don’t have to work that hard,” said Matt Garofalo, a senior at North Carolina. “You meet a girl at a late-night restaurant, she’s texting you the next day.”

But it’s not as if the imbalance leads to ceaseless bed-hopping, said Austin Ivey, who graduated from North Carolina last year but was hanging out in a bar near campus last week. “Guys tend to overshoot themselves and find a really beautiful girlfriend they couldn’t date otherwise, but can, thanks to the ratio,” he said.
Mr. Ivey himself said that his own college relationship lasted three years. “She didn’t think she would meet another guy, I didn’t think I would meet another girl as attractive as her,” he said.
Several male students from female-heavy schools took pains to note that they were not thrilled with the status quo.
“It’s awesome being a guy,” admitted Garret Jones, another North Carolina senior, but he also lamented a culture that fostered hook-ups over relationships. This year, he said, he finally found a serious girlfriend.
Indeed, there are a fair number of Mr. Lonelyhearts on campus. “Even though there’s this huge imbalance between the sexes, it still doesn’t change the fact of guys sitting around, bemoaning their single status,” said Patrick Hooper, a Georgia senior. “It’s the same as high school, but the women are even more enchanting and beautiful.”

And perhaps still elusive. Many women eagerly hit the library on Saturday night. And most would prefer to go out with friends, rather than date a campus brute.

But still. “It causes girls to overanalyze everything — text messages, sideways glances, conversations,” said Margaret Cheatham Williams, a junior at North Carolina. “Girls will sit there with their friends for 15 minutes trying to figure out what punctuation to use in a text message.”

The loneliness can be made all the more bitter by the knowledge that it wasn’t always this way.
“My roommate’s parents met here,” said Janitra Venkatesan, a student at North Carolina. “She has this nice little picture of them in their Carolina sweatshirts. Must be nice.”