Seattle-Tacoma Ranks Ninth on America’s Most Rodent-Infested Cities

April 05, 2018
Some lists are good to make, some aren’t. Sprague’s hometown of Tacoma and the Seattle metropolitan area were ranked as the ninth most rodent-infested city in the United States, according to a recent report.
 
The rodent most responsible for earning the Puget Sound region its dubious ranking is the rat. Norway rats were, for a long time, the most prevalent species impacting commercial facilities such as breweries, seafood processing and dairy plants, and food storage and distribution centers but the region now deals with both Norway and roof rats.
 
Unlike its ground burrowing relative, roof rats live high on the exposed structural beams, rafters and shelving inside a facility and in trees and bushes outside.
 
Sprague’s Technical Director Jeff Weier was recently interviewed by Seattle Magazine on the topic.
 
When asked what is driving up the rodent activity in the Puget Sound area, Weier said that increased development and construction has caused the physical disruption of rodent nesting sites thus displacing them and leading to more intrusions inside structures. 
 
“There used to be open fields and lots everywhere and they’re all being filled in with structures,” Weier told the magazine. “And, of course, when we build in their environment, we invite them in, basically.”
 
 
When it comes to rats, there is quite a dossier on the disease-carrying, food-spoiling and wire chewing Norway and roof rat. The aggressive Norway rat is the most commonly encountered of the pair but don’t underestimate the roof rat’s destructive capabilities. Roof rats often chew through insulation and wires and can threaten a building’s structural integrity.
 
Here are some interesting rat facts:
  • Rats in urban areas normally live 5 to 12 months.
  • Active rat burrows have a smooth, well-worn appearance at the entrances due to the high traffic volume.
  • Rats do not like sudden changes or new objects to their environment. This behavior is known as “neophobia.”
  • Norway rats will venture up to 450 feet from their nesting sites in search of food.
  • Norway rats are adept swimmers and often use waterways (i.e. sewers) as a means of moving between feeding and harborage sites.
rat walks on branch in summer park

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