June 3, 2009 -- Urban rats rarely stray from their own alleyways, found a new study, but a few adventurous individuals make city-wide treks. Understanding how rats move around may aid efforts to eradicate them, said lead researcher Gregory Glass, an infectious disease biologist at Johns Hopkins University in Baltimore. The mangy rodents spread diseases, damage buildings, and cause psychological stress. "It's a public health issue at a number of different levels," Glass said. "People just don't like rats running around." As attention-grabbing as rats can be among homeowners, scientists know surprisingly little about their basic biology, said Lawrence Heaney, Curator of Mammals at the Field Museum in Chicago. Most rat research so far has involved simply watching what the animals do at night. Based on those studies, scientists have long assumed that rats are homebodies. "They just don't go far," Glass said. "They come out of their burrows. They walk to the nearest trash can and grab something to eat. They go to the nearest puddle and drink some water. They walk around a bit. And they go home." Related Content:
Yet, every time rats are eradicated from an area, new ones eventually move back in. So, at least some rats must be traveling further distances. To get a more accurate idea of how mobile Baltimore's city rats really are, Glass and colleagues turned to genetics. The scientists collected DNA from more than 275 rats that lived in 11 areas of the city. By comparing key regions of the animals' genomes, the researchers were able to see how closely related each rat was to the others, both nearby and far away. Analyses revealed that Baltimore's rats tend to mingle mostly within their own small communities. Inside those neighborhoods -- which spanned about 100 meters, or the length of a city block -- rats are more genetically similar to each other than they re to rats that live in other parts of the city. Get More NewsSpiders, Scorpions Among World's Oldest CreaturesMany creepy crawlies have been on Earth much longer than previously believed.Blood-Sucking Vampire Bats Sing DuetsWhite-winged vampire bats "harmonize" with separated roost mates.Oldest Hebrew Writing Possibly FoundAncient inscriptions on a 3,000-year-old pottery shard could make history.Rare, Prehistoric-Age Reptile Found in N.Z.A tuatara has been spotted on the New Zealand mainland for the first time in 200 years.Iceman Has No Living RelativesOetzi, the 5,300 year-old frozen mummy, left no living genetic legacy.SLIDE SHOW: Landscapes of TerrorWhat makes a place feel scary? There are scientific explanations.It's Official: People Are Warming the PolesHumans are conclusively to blame for polar warming, say scientists.Eight-Armed Animal Preceded DinosaursWhat may be one of Earth's first animals was no bigger than a coaster and had eight arms.Phoenicians Live on in People's GenesOne in 17 Mediterranean men may be descended from ancient Phoenicians.Pesticides, Fertilizers Linked to Frog DeclineA pesticide is found to promote parasites among amphibians.Hubble Telescope Taking Photos AgainThe Hubble Space Telescope is once again snapping stunning photos of the universe.Andean Mummy Hairs Show Hallucinogen UseScientists find direct evidence of hallucinogenic drug use among ancient Andeans.Opals on Mars Reveal Planet's Long Wet PastOpals found on Mars suggest the planet has been wet for much longer. |
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