They are big. They are vicious. Some say they are albinos, because of a lack of sunlight.
They are the alligators that supposedly infest New York City's sewer system, slithering through the bowels just under the street level, feeding on rats and rubbish and terrorizing sewer workers armed with guns for self-defense.
These gators may be the city's most entrenched urban myth, one that has permeated pop culture and has become a recurring theme in books, television shows and movies.
That century-old myth has spawned hoaxes and art projects. It has even become an official quasi-holiday in the city: Alligator in the Sewer Day is in February.
And the tales are sort of true. The city rescues several alligators a year, typically former pets that have been abandoned after having outgrown their cute phase.
With every new sighting, the legend gets another boost.
Reports in The New York Times of alligator sightings in the New York area go back more than a century. A 1907 article described a worker in Kearny, a New Jersey town about 12 miles from Midtown Manhattan, who was bitten by a small gator while he cleaned out a sewer.
By the 1930s, news proliferated about sightings in and around New York City.
Alligator sightings sometimes prompted hunting expeditions, such as one in 1932 after several of the reptiles disappeared from captivity in Belleville, a town along the Passaic River in New Jersey.
The same year, the police mobilized a hunt in Westchester County, just north of New York City, after two boys brought in a 3-foot dead gator and claimed that the Bronx River was swarming with live ones.
Armed with fishing nets and chunks of calves' liver, officers combed "the jungles of the Bronx River to capture alligators for the Bronx Zoo," The Times reported, adding that the hunt was discontinued when the police realized that the boys had merely found an escaped pet.
By the 1930s, advertisements for purchasing baby gators by mail were common in magazines, including Popular Mechanics. Vacationers to Florida would also bring back the reptiles as souvenirs.
Once the cute pets got too big, the theory goes, they would often wind up in the sewer after being flushed down a toilet or dumped into a street drain.
"It was a time when all these alligators were being brought up to New York and either escaping on their own or being let loose by unhappy parents," said Michael Miscione, a former Manhattan borough historian.
The seminal New York City sewer-gator event came on Feb. 9, 1935, when some East Harlem teens spied an alligator down a storm drain and then lassoed and hauled it up with a clothesline. After the reptile - roughly 8 feet long and 125 pounds - snapped at them, they killed it with their shovels.
"Alligator Found in Uptown Sewer," read the headline in the The Times. The article speculated that it had escaped from a passing steamer in the East River and had swum into a sewer outflow pipe.
"The charm of the 1935 sighting was that it was discovered by young boys and was the talk of this working man's neighborhood of East Harlem during the Great Depression," Miscione said.
In 1937, a barge captain pulled a 4-foot, 8-inch alligator out of the East River by lassoing the animal around its "wildly waving forefeet," reported The New York Herald Tribune. "The tropical visitor was clearly exhausted and seemed in no humor to fight," the newspaper added.
A week later, a 2-foot alligator crawling along a Brooklyn subway platform shocked waiting passengers after crawling out of a trash can where it had apparently been dumped.
A police officer pounced on the reptile, managing to avoid its snapping jaws while another officer tied them shut.
By the 1960s, sewer gators had found their way into numerous cartoons and books, including Thomas Pynchon's 1963 novel "V," in which little gators could be purchased from Macy's for 50 cents and the character Benny Profane makes a living hunting albino white alligators "alive and breeding" in the sewer system.
The 2002 children's book "Alberto the Dancing Alligator" follows Alberto's journey down one toilet and through the underground water system before he surfaced in other toilets and sparked a citywide gator scare.
In a 1982 column in The Times, Anna Quindlen interviewed a New York City sewer chief, John T. Flaherty, whom she called the city's "resident expert on the most durable urban myth in the history of cities, reptiles or waste disposal."
Flaherty's list of sewer sightings includes rats, insects, stray fish, dead bodies and even street-gang clubhouses - but no gators.
Yet, he said, he constantly responded to letters from people asking about albino gators, or wondering if sewer workers did indeed carry pistols "to protect themselves from the ravages of rapacious reptiles."
In 1982, a 2-foot alligator was found swimming in a Westchester County reservoir that is part of New York City's water supply.
The city's Department of Environmental Protection, which oversees the sewer and drinking water system, organized a boat expedition to capture the gator, which workers lassoed and gave to the Bronx Zoo.
Inquiries from around the world about sewer alligators are still fielded by the department, whose mascot was once a sunglasses-sporting gator emerging from a manhole. The city sold T-shirts with that mascot and the slogan, "The legend lives ..." for years.
The gator legend also inspired the Leatherhead character, introduced in 1987, in the "Teenage Mutant Ninja Turtles" comics and video games. Flushed down the toilet as a pet, he becomes a giant mutant alligator who lives in the sewers.
In the past couple of decades, New York has had sporadic street-level sightings and rescues. Prominent ones included the 4-foot gator pulled out of Kissena Lake in Queens in 1997, and the 2-foot-long caiman caught in Central Park in 2001.
A 3-foot gator found by a dog walker in Alley Pond Park in Queens in 2003 was promptly named Alley-Gator by park officials. And a 2-foot-long baby crocodile was spotted under a car in Astoria in 2010.
At the time, a police spokesman seemed to anticipate a reporter's question
"Before you ask," the spokesman said, "no cops could confirm it came out of the sewer."
The nonprofit Animal Care Centers of NYC, which runs the city's animal shelters, has handled five alligators in the past two years, a spokeswoman, Katy Hansen, said.
Most rescues, she said, were pets. Some have come from the outdoors, she added, but none from sewers. They are rarely more than 3 feet and are placed in a sanctuary.
"People get them as pets," Hansen said, "but then they grow and people say, 'What am I going to do? It's in the bathtub.' And we have to come get them."
Experts say the water in New York's sewers is too cold and toxic for alligators to survive very long, especially if they're eating rats and raw sewage.
The conditions have led to the myths of special breeds - that the lack of sunlight creates blind, albino gators, and a steady diet of toxic waste produces giant, mutant alligators.
More simply, Flaherty, the sewer chief, said in 1982 that alligators would be likely to succumb to the volume of water rushing through mains during heavy rainfalls - or to a food source that "has been, to put it as delicately as possible, predigested."