There are roughly 1,500 rodent species around the world, many of which are benign. Others, however, have long wreaked havoc on human populations. People often wonder: Where do rats come from, and where do rats live? The following article will answer those questions, as well as offer advice on what to do if your home becomes rat infested.

Two of the most dangerous and widespread rodents are the black rat — known scientifically as Rattus rattus — and the brown rat — referred to as Rattus norvegicus. These two originated in Asia but have since infested many other regions.

Both types of rats carry disease-causing pathogens that can spread to humans through bites, scratches and food contamination. The black rat is common throughout the Orient, the Indian Subcontinent, the Middle East, most of Africa, Continental Europe and Oceania. The brown rat has spread even further, with major populations established across North and South America, Australasia, Africa and Eurasia.

Top 10 Places in America Known for Large Groups of Rats

New York City has long been notorious for its widespread rat infestations, but America's largest city has actually been ousted from the top spot in the ranking of rodent densities. According to a recent pest control survey, a big city in the Midwest has overtaken the Big Apple as the nation's rat capital.

1. Chicago, Ill. – Second City is currently ranked as America's No. 1 rat hub. Despite that distinction, city officials have found a unique way to keep the problem under control — with the help of coyotes. Tracked with radio collars, the canids are set to roam about in areas where rat densities are known to form. Since rats comprise the bulk of a coyote's diet, this new job has been quite appetizing for the wolf-like creature.

2. Los Angeles, Calif. – The City of Angels is famous for being one of the entertainment capitals of the world, and the rats have been filtering in for their own shot at fame. The critters have been no sweat for the LAPD, however, which has employed dozens of feral cats to hunt down their natural enemy. In a town where everyone's looking for a lucky gig, the felines have it made.



3. Washington, D.C. – Rodents have also been swarming in the nation's capital, where in 2014 a former morgue contractor reported having been attacked by rats at D.C.'s Providence Hospital. According to some of the hospital's employees, rats have run the building for more than four decades.

4. New York City, N.Y. – America's largest city is always bound to rank highly in terms of rodent density. With numerous shipping docks, abandoned properties and vast amounts of subway space, the Big Apple is virtually a magnet for all sorts of nibbling, disease-carrying critters. One of the most ghastly examples of infestation in NYC came to light through a 2007 viral video that revealed a swarm of rats crawling around inside a Greenwich Village Taco Bell/KFC outlet in the pre-morning hours - Watch the Video Here.

5. San Francisco, Calif. – Earthquakes aren't the only threat in the nation's steepest city — the City by the Bay is also plagued with rats. In recent years, a big part of the problem has been attributed to a 43-year-old woman named Eric J. — aka "Rat Girl" — who lives with up to 300 rats at a time. Reportedly, this rat fanatic purposely breeds rats to release into the wild. Her breeds are also said to have infested every building in which she's taken up residence.

6. Seattle, Wash. – Aside from being home to the Space Needle, the Emerald City might seem rather anonymous on the national map, but its rat count has grown to distressing proportions. Between 2008 and 2009, city officials counted 140 complaints from residents who reported spotting rats in toilets.

7. Detroit, Mich. – Reports of infestation have been on the rise in the Motor City, where the problem has been attributed to human carelessness, such as improperly stored trash, poorly maintained houses, etc. However, city officials have arranged some unique methods to get the public involved in stamping out the problem. Public awareness campaigns and lessons in garbage storing are among the solutions geared towards helping residents. In the suburb of St. Clair Shores, they've even proposed $5 for each dead rat through an urban bounty program.

8. Cleveland, Ohio – Say what you will about the Rock and Roll Hall of Fame, but Cleveland's most famous museum could have cursed the city by not inducting legendary Irish rockers The Boomtown Rats. As any knowing local is apt to sing, "It’s a rat trap Judy, and we've been caught!" Hear that, Sir Bob?

9. Baltimore, Md. – As one of the central locations for rat research — at John Hopkins University, —Baltimore was destined to make the rattiest city list. No other story illustrates the city's problem more than one case in which rodents tunneling below a stretch of pavement made the soil so weak that a garbage truck driving over-ground sank axle-deep. Within seconds, the over-spilled trash became a literal feeding ground for hungry rats. Due to the prominence of rats in Baltimore and the health problems they can cause, Baltimore County is working with a licensed exterminator to treat areas that have been affected by rats. The rat control program is called “Rat Attack".

10. Miami, Fla. – One of the nation's most vulnerable cities to the threat of rising sea levels is also a hotspot for rats. The area known for pink flamingos has not just seen an influx of rats — it's seen big rats. On nearby Grassy Key, some of the rats have measured up to three-feet long. This supposedly having stemmed from an exotic breeder who let a handful of such specimens escape in the late ’90s.

Top 10 Places in the World (Outside the U.S.) Where Rats Live in Large Numbers

London, England – In recent years, rat densities have thrived in Ol' Blighty. Due in part to the depressive effects of the 2008 recession, not to mention construction efforts for the 2012 Olympics, London is up to its ankles in rats. Unfinished structures have served as breeding grounds for infestations, as have abandoned buildings, where the critters can find darkness, nibbles and water. Perhaps the scariest aspect of London's rat problem is the size of the rodents, some of which are reported to be twice as big as the average specimen.

Paris, France – The City of Light has long been idealized as the world's most romantic mecca. While this might be based on an archaic concept of the city dating back to Hemingway's time, one thing is certain: Paris is a city of rats. Parisian officials claim that the local rat density hovers around eight million, a figure that outnumbers the city's human population four to one. The problem has gotten so bad for residents that the city has called upon everyone to step up their efforts to eradicate the critters. As part of a campaign known as Le Smash, locals are required to clamp down on rats by setting up traps, dialing catchers, laying out poisons and blocking entry points to buildings. Locals who get ratted out for not doing their part could end up facing fines.

Karni Mata Temple in Deshnoke, India – Deshnoke is home to one of the world's densest rat swarms, thanks to a custom at Karni Mata Temple in which people come to worship a breed of nearly 20,000 rats. Believed to be a holy creature at this temple, visitors consider it a blessing to be touched by the rats and sample the same foods. Some visitors even hold contests of who can spot the largest number of rare white rats among the mostly brown rodent population.

Birmingham, England – London may be the capital of … well, rats, but England's third-largest city is vying for the crown. In 2014, Brummies reportedly made 14,812 rat distress calls. Experts blame the recent surge in rats and other pests on budget cuts in the city's pest control department.

Bukit Batok New Town, Singapore –Recently the location of a viral video about a rat colony, the new town's rodent problem is supposedly due to the feeding of stray dogs, who've left food nibbles all around the MRT station where most of the nesting has occurred. Pest control experts are currently working to eradicate the burrows without harming local dogs.

Hamelin, Germany – Seven-hundred years after the Pied Piper lured millions of rats to their deaths, the critters have returned to Hamelin, and they've gnawed away at the power lines of a popular city water fountain. Heck, the little buggers have always owned the water of any turf they stake.

Guangzhou, China – Some people will eat anything. In the Chinese port city of Guangzhou, it turns out there are some people willing to eat rats. Scooping up vast amounts of the more than two billion rats displaced by a nearby lake flood, local restaurants are advertising dishes of one kilogram of rat meat for 136 yuan.

Johannesburg, South Africa – The largest city of this nation is crawling with rats — lots of them! The city has earmarked 2.5 million South African rands in its fight against the critters. So far, the city is succeeding — over 28,400 rats have been caught in the township of Alexandria alone since March 2012.

Montecristo Island, Tyrrhenian Sea – While this four-square-mile island off the coast of Tuscany — famed in a classic Alexandre Dumas novel — is uninhabited by humans, during the late noughties it saw a spike in black rats. Supposedly, vermin that arrived by ship set the population spinning. The Italian government struck back with poison pellet aerial raids, but they haven't proclaimed victory.

Rat Island in the Aleutians – For over two centuries, an isle in the Aleutian cluster of islands between Alaska and Russia was notorious for its rat infestations and was referred to as "Rat Island." The problem was introduced to this island via ships that crashed ashore with stowaway rats. In the majority of these introductions, the rodents wreak havoc on the local ecosystem by killing off domestic species. Seabirds and island reptiles are the most common victims.

Fortunately, Rat Island qualifies for a new name as of 2010, because the eradication efforts succeeded in conquering the rodent problem. Since that time, bird populations that once thrived on the island are emerging in greater numbers to reclaim the land that had long been taken from them.

When Homes Become Rat Infested

Considering how one mother rat can breed up to 15,000 offspring's annually, infestations can easily spiral out of control in cities like those listed above, all of which offer hospitable living conditions for rodents. The creatures feed on human resources, leaving it up to residents to collectively work at combating the problem. The issue is to some degree seasonal, with surges in rodent activity witnessed in fall months. These are months when temperatures start to drop, and the critters invade homes in search of water, food and shelter.

What most homeowners don't even realize is just how easy it can be for rats or mice to gain entry — such critters can slip through coin-sized holes in walls, floors and ceilings. Rodents will often start at tiny holes and then chew around the circumference until the opening is large enough to slip through. Starting in the month of October, sightings of rodents typically occur with relative frequency.

If rodent damage has plagued your home, it's important to find out which kind of rodent is responsible and have it eradicated accordingly. To get to the bottom of a domestic rodent issue, contact the rodent control specialists at Victor®.

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