Technically, they aren't rats, but "muskrat catcher" is a profession in parts of Europe. https://en.wikipedia.org/wiki/Muskrat#In_human_history:
"In some European countries, such as Belgium, France, and the Netherlands, the muskrat is considered an invasive pest, as its burrowing damages the dikes and levees on which these low-lying countries depend for protection from flooding. In those countries, it is trapped, poisoned, and hunted to attempt to keep the population down"
http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/All/agd...