There is hardly a New Yorker who hasn’t seen Rattus norvegicus scurrying along an empty train track or rooting around a garbage bag. Although one gets a gnawing feeling that rat sightings have been in the news a lot recently, the creatures have a long history of nauseating New Yorkers.

Many watched last month as rats nearly turned a Greenwich Village KFC/Taco Bell into a Cirque de Soleil stage, resulting in subsequent fast food restaurant closings and the removal of a health inspector.

The current situation does not compare with an infamous incident in 1979, when rats attacked a woman walking on a street. Mayor Koch recalled being informed that 300 rats had crossed Ann Street: “So I said, ‘This is hard to believe. Did they wait for the stoplight to change?’ Of course not. They believed it was their turf.” He later heard there had been construction in the area. That always upsets rats, he told The New York Sun. “They don’t like to be disturbed,” Mr. Koch said.

No one knows exactly how many rats are now in New York City or were then, the curator of mammals at the Bronx Zoo, Patrick Thomas, said. He guessed there are probably more today than a hundred years ago, when the city was smaller.

Whatever their number, they get little respect. The author of “Rats,” Robert Sullivan, cites the “perverse celebrity status” of “nature’s mobsters.” Indeed, it is no compliment among gangsters to say one “ratted” on someone, and labor leaders places large inflatable rats in front of buildings where companies use practices they deplore.

Rats probably came to America with the early European explorers ships in the mid-1500s, Mr. Thomas said. But as Mr. Sullivan once said at a downtown reading, “There’s not a lot of ‘When did rats come to America?’ scholarship out there.” In his book, Mr. Sullivan notes that the first professional rat catcher was Walter Isaacsen of Brooklyn, who used poison grains in 1857.

During that century, a popular gambling activity in rough neighborhoods along the water was “rat baiting,” the public historian at the New-York Historical Society, Kathleen Hulcer, said. Sailors would bet on rats fighting to the death, “They would keep throwing more rats in for the victor to chew up,” she said. “It was a mini-gladiator spectacle.”

Not all violence occurred in betting situations. Mr. Sullivan described a florist in Murray Hill who in 1897 tried to kill a rat with some scissors and accidentally gored a policeman. Then there was the famous Rikers Island rat battle of about 1915, when rats took over the place and snakes were nearly brought in to help kill them. Problems with rats continued such that Mayor O’Dwyer even appointed a rat specialist in the mid-20th century. A former parks commissioner, Henry Stern, even tried to set up elevated owl houses in Central Park to combat rats.

Perhaps it is natural to fear creatures that can exert pressure of up to 7,000 pounds a square inch and are capable of gnawing through concrete. A professor of anthropology at the New School, Hugh Raffles, said these predators are smarter than roaches and “get into our lives” in a way that other beings such as bees do not. A professor at the University of Chicago, Martha Nussbaum, said she agreed with researchers such as Paul Rozin that entities that evince disgust are reminders of decay and animality. Mr. Koch noted that people hate rats from an early age, adding, “I believe it’s a properly directed hatred.”

One who does not hate rats is illustrator Drusilla Kehl, who has 23 so-called fancy rats as pets. She said domestic rats are as different from street rats as a pedigreed dog is from a wild dog. One thing the pet and wild rodents have in common is “they live short and breed fast.”

There is a lighter side to rats in popular culture. Ms. Hulcer once borrowed an illustrated rat Valentine from Ms. Kehl and her partner, Mark Kaplin, for a NYHS show called “Petropolis.” Ms. Kehl also said there was an upcoming Pixar film called “Ratatouille,” about a rat in Paris that wants to become a chef. She said she knows of a New Yorker who scalped a Barbie doll to make a little wig for her pet rat.