In this one building in Iraq, our network started to deteriorate and finally became unusable. We found packet loss just from our room to the switch was basically total. Our "office" -- an old game butchering room when Saddam used it as a hunting lodge -- had the nicest wiring of any office on that base, everything in panduit (flat surface mounted conduit) and properly spaced.
We pulled off the panduit covers and suddenly mice went scurrying everywhere. Our cables were naked, in many places down to pure copper. There were little piles of CAT 5 insulation and nest debris for about 30' on 3 separate runs.
At ISAF HQ in Kabul, there was no problem with rodents. They had a catch, neuter, and release program for stray cats.
At another base in Kabul, we started to see mice everywhere. Then a mama cat moved into our logistics tent and dropped a litter of 4 kittens. Shortly, all the mice disappeared. One evening I went behind the logistics tent and mama was teaching one of the kittens to hunt. The mouse was long since dead, but the kitten would through the mouse in the air and then pounce on it as it landed.
...and the eco-whackos say we're the only species that hunts for sport.
Obviously, they've never seen cats.