Gray squirrels are so plentiful in cities today that it is difficult to imagine urban life without them. But their introduction to Minneapolis parks in the early 1900s was carefully orchestrated by park superintendent Theodore Wirth. Reporter Susan Du joins host Eric Roper to discuss how Wirth supplanted red squirrels with gray ones -- and the pitfalls of attempting to control nature.LINKS:Did a famed parks leader import gray squirrels to Minneapolis — and have the red ones killed? (January 2023 Curious Minnesota story)