A\u00a0new report\u00a0by the apartment search service RentHop has named Chicago the \u201crat capital\u201d of the country. To come to that conclusion, researchers examined the number of rat complaints in Chicago and three other cities during 2017.\r\nKey findings from the report: Chicago\u2019s whopping 50,963 complaints last year put it well ahead of New York City (19,152), Washington, D.C. (5,036) and Boston (2,488).\r\nEven after looking at the number of complaints per 100,000 residents, Chicago still ranked number one.\r\n\u201cThe abundance of garbage and buildings in The Windy City makes it a great location for these rats to seek shelter and food for survival,\u201d the report states.\r\nHere are five things to know about Chicago\u2019s rat population:\r\n1.\u00a0The rat breed found in Chicago is the brown rat, also known as the Rattus norvegicus \u2013 the Latin name for the Norway rat. The black rat, also called the tree rat, used to dominate Chicago\u2019s streets but is now found on the West Coast, said Don Opitz, an associate professor and interim dean at Depaul University\u2019s School for New Learning.\r\nAlthough there aren\u2019t many differences between the two breeds, brown rats are considered to be more dominant, and \u201cthat\u2019s because of how successful the brown rat has been in defending its territory. It has edged out the black rat, and that\u2019s why the black rat has fled to the West Coast,\u201d said Opitz, who teachers the course \u201cLiberal Arts in Action: Rats in the City.\u201d\r\n2.\u00a0According to the city\u2019s\u00a0Department of Streets and Sanitation, the brown rat\u2019s average life span is 6-12 months. Female rats begin reproducing at about 2-3 months old, but can start as early as 48 hours old. They produce 4-7 liters per year with each litter containing 8-12 pups.\r\n3.\u00a0Brown rats prefer to live in burrows, they\u2019re excellent at swimming and climbing, and they\u2019re most active at night.\r\n\u201cThere\u2019s really nothing distinctive about the rats that makes them different from gerbils, or mice or other rodents that we keep as pets,\u201d Opitz said. \u201cIn fact, rats are very smart and they\u2019re probably the smartest rodents.\u201d\r\n4.\u00a0Despite the number of complaints listed in RentHop\u2019s report, DSS said it received 42,670 requests for rodent abatement. The difference in numbers comes after factoring in duplicate requests and proactive abatement jobs completed by crews, said Marjani Williams, spokeswoman for DSS, in an email to Chicago Tonight.\r\nShe also said projections for 2018 already show a reduction in the number of rat complaints.\r\n5.\u00a0Chicago\u2019s rodent abatement measures include poisonous pellets and two pilot programs: one that uses dry ice in burrows, which later melts and turns into carbon dioxide to suffocate the rats; and another that uses ContraPest, a poison that makes rats infertile.