It was in the late 19th century that landscape parks really took root and cities began implementing wide expanses of green space. With an understanding that nature and fresh air were efficacious curatives for the maladies that ailed, “pleasure grounds” and urban parks became a place to enjoy the health-giving effects of nature.

And as parks became more prominent, squirrels became the focus of attention, as Etienne Benson of the University of Pennsylvania writes in the Journal of American History. Urban reformers, who thought of the squirrel as a rural mascot, wanted to bring the animal in to places like Manhattan’s Central Park in order to create “a bucolic atmosphere that was entertaining, enlightening, and salubrious.” In 1847 three squirrels were released in Philadelphia’s Franklin Square and were provided with food and boxes for nesting.