Roof Rat General Information
(black rat, ship rat)
Rattus rattus Linnaeus
History of Roof Rats in Maricopa County
Roof rats were first discovered in East Phoenix’s Arcadia District in 2002. Not native to Arizona, the
rats are believed to have been transported to Maricopa County from one of our neighboring coastal states.
In 2004, roof rats were spotted in cities in towns all over the Valley. This confirmed to the County that the
rats were being transported unknowingly either through residents moving from one home to another or perhaps from
residents moving into the Valley from our neighboring coastal states.
Although roof rats have not been found to have disease, they are known to be very destructive,
gnawing through wiring and destroying citrus.
In the County’s early experience with roof rats in Arcadia, we attempted to use all of our government
resources to eradicate the rat problem. To do this we put up over 6,000 bait stations on every telephone pole
and tree on public land in Arcadia. The result was that the rats consumed only about 1 percent of the poison
in the bait stations.
On the other hand, residents that were cleaning up their yards and placing bait stations and traps on their own
property were having much more success at ridding their homes of rats. What was learned about the rats is that
they are rodents of routine and unless absolutely driven to a foreign pole or tree, they prefer to stay right
in a residential backyard.
This experience has allowed the County to have a deeper understanding of what it takes to eradicate rats on a
residential property. Eradication of roof rats in any neighbor hood is a team effort and requires the relentless
effort of the whole neighborhood. This website is a primer to educate residents about just what it takes to keep
roof rats out of your neighborhood.
Please Note: Maricopa County does not provide bait stations or traps to the public. Bait stations can be
purchased at cost through Barry Paceley at http://www.roofrat.net.