by the 1970s, the siberian chipmunk inhabited suburban forests and urban parks in belgium, france, switzerland, germany, italy, the netherlands, and austria. this is mostly caused by owners releasing these animals because they no longer wanted them as pets, or the owners purposefully freed the chipmunks to live naturally in the wild. other siberian chipmunks escaped from captivity and inhabited the forested areas of europe. the dutch chipmunks for example are escapees from a former zoo in tilburg. when the zoo was shut down and all animals were moved away, many chipmunks got forgotten due to their underground residence. while thousands of animals were introduced to new environments, their naturally slow spreading, 200 to 250 meters per year, prevented them from rapidly moving to areas far beyond where they escaped.