Scientists find city rats are loyal to their 'hoods'

May 26, 2009
Rats in Baltimore, and likely other urban areas, are loyal to their neighborhoods. Credit: City of Baltimore

In the rat race of life, one thing is certain: there's no place like home. Now, a study just released in Molecular Ecology finds the same is true for rats. Although inner city rodents appear to roam freely, most form distinct neighborhoods where they spend the majority of their lives.

Like any major city, Baltimore has many lively neighborhoods - each with its own personality. But scientists from the Johns Hopkins Bloomberg School of Public Health say humans aren't the only Baltimoreans loyal to their 'hoods. The researchers found that rats typically stay close to home, rarely venturing more than a city block. In the face of danger, however, some rodents can travel as far as 7 miles to repopulate abandoned areas.

Wild Norway rats - also called wharf rats, sewer rats or brown rats - can weigh nearly 2 pounds and transmit a variety of diseases to humans. Despite expensive eradication efforts, the number of rats in Baltimore has remained unchanged over the past 50 years. To understand why, researchers trapped nearly 300 rats from 11 residential areas of Baltimore and conducted genetic studies to see how the rats were related.

The scientists found that East Baltimore rats are separated from their unrelated West-side counterparts by a large waterway known as the Jones Falls. Within these hemispheres, rat families form smaller communities of about 11 city blocks. Each community is further divided into neighborhoods that span little more than the length of an average alley. And to a rat, this is home sweet home.

The findings suggest that while rats rarely migrate, neighborhood eradication efforts may backfire by encouraging the rodents to repopulate other areas and further spread disease. When you smell a rat, the researchers say, the best solution may be to tackle the problem on a much larger scale - perhaps by targeting entire families at once. Rat race won.

More information: Commensal ecology, urban landscapes, and their influence on the genetic characteristics of city-dwelling Norway (Rattus norvegicus), L. C. Gardner-Santana, D. E. Norris, C. M. Fornadel, E. R. Hinson, S. L. Klein and G. E. Glass DOI: 10.1111/j.1365-294X.2009.04232.x

Source: Wiley (news : web)

Explore further: Nature offers video of 10 cutest animals of 2014

add to favorites email to friend print save as pdf

Related Stories

Smelling a rat to catch a rat

Mar 24, 2008

A novel experiment using laboratory rats to attract wild rats could pave the way for “rat perfumed” bait capable of reducing the millions of rats threatening New Zealand’s native species, say Massey ...

Scientists discover 21st century plague

Nov 24, 2008

Bacteria that can cause serious heart disease in humans are being spread by rat fleas, sparking concern that the infections could become a bigger problem in humans. Research published in the December issue of the Journal of ...

If you're feeling helpless, it's best to be alone

Jan 02, 2008

If you're going to experience a period of helplessness, it's best to be alone. New research at the University of Haifa found that laboratory rats that were on their own when exposed to uncontrollable conditions, which create ...

Recommended for you

Nature offers video of 10 cutest animals of 2014

1 hour ago

(Phys.org)—The journal Nature has released a video that ventures a bit from its traditional strictly-science approach to technical journalism—it's all about the cutest animal stories of the past year ( ...

Big data and the science of the Christmas tree

4 hours ago

Often called the "Cadillac of Christmas trees," the Fraser Fir has everything a good Christmas tree should have: an even triangular shape, a sweet piney fragrance, and soft needles that (mostly) stay attached ...

Study shows starving mantis females attract more males

Dec 17, 2014

A study done by Katherine Barry an evolutionary biologist with Macquarie University in Australia has led to the discovery that a certain species of female mantis attracts more males when starving, then do ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.