"While several species of rats are native to America, such as the cotton, the Florida and the Rocky Mountain rat, the common black, brown(norway) and gray house rats are "illegal aliens of Old World origin".............."Both the black and the brown rat are believed to be natives of China".............."Westerners generally are horrified by the thought of eating rats because of their uncleanness and repulsive appearance".............."But these animals are a regular article of food in many parts of the Orient"............"Native American rats differ considerably from house rats".............."The wood rat, for instance, is cleanly in habits, eats food of an unbjectionable nature and has flesh that is said to be palatable and wholesome"................"Rats are not mentioned in the Bible and they are not referred to in Greek and Roman literature, although a medieval legend says that Abdera, an ancient maritime town in Thrace, became so overrun with rats that all the inhabitants abandoned the place and removed to Macedonia".................."The world-wide distribution of house rats resulted from world-wide commerce"............... "Some authorities suppose the Crusaders brought the black rat from the Near East"................."During the latter part of the Middle Ages this species was the common house rat on the continent".............."The brown (Norway) rat did not appear in Europe until about 1727 when great numbers of them swam across tile alga and established themselves in Astrakhan, whence they spread westward to Europe and finally to America"..............."The black rat was introduced into the New World from Europe as early as 1554"..........."There may have been members of this species on the Mayflower"................ As Chicago knows so well(and the article below expounds on), House rats are among the most destructive pests in the world"............"Despite previous studies indicating that rat populations are often larger in areas of cities with high rates of vacant or abandoned buildings, researchers found fewer rats on vacant properties in Chicago"....And where people rent rather than own their dwelling, rat populations swell, apparently due to renters not securing their trash as dilegently as homeowners............."They are hard to exterminate because they are prolific, omnivorous, agile and resourceful"................"A rat can jump vertically to a height of two feet or more........."It can drag objects from place to place by means of its tail. Rats are common disease-carriers and probably have been responsible for more human deaths than all the wars of history"

https://news.wttw.com/2018/11/28/chicago-rat-study-shows-correlation-between-rental-units-and-rodents

Chicago Rat Study Shows Correlation Between Rental Units and Rodents

Alex ruppenthal, 11/28/18

Brown(norway) Rat

Chicago’s recent designation as the country’s “rat capital” can be attributed in large part to a particular type of home: rental units.

A new study by researchers from Lincoln Park Zoo found that areas of the city with a high rate of renter-occupied units had more rats than neighborhoods where owners make up a larger portion of residents.

What’s behind the trend? Although more analysis is needed, researchers said one potential reason is that renters and off-site building managers could be less concerned with taking steps to control rat populations as compared to owners, who have more of a stake in the long-term condition of their homes.

“This discovery is quite interesting,” said Maureen Murray, a wildlife disease ecologist at the zoo’s Urban Wildlife Institute and Davee Center for Epidemiology and Endocrinology, in a statement. While acknowledging that more research is needed, Murray said the disparity is “presumably due to the responsibility of maintenance being on the property owner rather than the tenant.

The study, published Wednesday in the journal Frontiers in Ecology and Evolution, notes that rats have been estimated to cause more than $27 billion in damage to consumer goods each year in the U.S. The rodents can also transmit harmful pathogens to humans.

Public rat complaints in Chicago have increased by nearly 40 percent over the past decade, up to nearly 46,000 complaints last year alone, giving Chicago the most rat complaints per capita of any U.S. city, according to the study.

In examining the city’s rat problem, Murray teamed up with Arlington Heights-based Landmark Pest Management to determine whether areas with more rat complaints actually have more rats. The objective was based on an understanding that rat complaints might not accurately reflect the number of rats in a certain area, given that the likelihood of reporting complaints can be driven by factors such as income, location and trust in local government.

Working with Landmark’s pest management staff, Murray’s team trapped brown rats in 13 community areas that were selected to represent a wide range of average income levels and development.

In each area, rats were trapped in the two alleys with the highest number of complaints, as indicated by data from the city’s Department of Streets and Sanitation.

Black Rat

After recording the number of rats trapped in each location, researchers compared their results to nearly 370,000 complaints made to the city’s Bureau of Rodent Control between 2008 and 2018.

They found that despite the various factors influencing whether residents file complaints, areas with more complaints did in fact have more rats. The finding, researchers said, demonstrates that public rat complaints can be an effective tool for cities to use in targeting rat prevention efforts.

Another finding shows – unsurprisingly – that alleys with more rat complaints and rats trapped also had larger amounts of uncontained garbage. This shows that city-wide rat control initiatives must consider strategies not just for rats but also for underlying issues of waste management, researchers said.

“Stash your trash,” Murray said in a statement. “The easiest way to ensure rats stay at bay is to secure trash in closed bins.”

Despite previous studies indicating that rat populations are often larger in areas of cities with high rates of vacant or abandoned buildings, researchers found fewer rats on vacant properties in Chicago. Researchers said the finding is in line with a growing appreciation for the ecological value of vacant lots in cities, a phenomenon that could be ripe for further study, they said.

“Rats – whether we like it or not – are a part of our ecosystem,” Murray said in a statement. “They are a fascinating species that we actually have relatively little research available on, and we aim to change this.”

The Lincoln Park Zoo-Landmark study is ongoing, and researchers plan to explore questions related to stress levels in rats, disease prevalence and indicators of risks to public health.