By AP/KWMU
Springfield, Ill. – Illinois has added the rare Franklin's ground squirrel to its list of threatened species.
The action by the Illinois Endangered Species Protection Board makes it illegal to kill the grayish-brown mammal.
Board president Dan Gooch says there's evidence that the squirrel's population is dwindling and it could become extinct if something isn't done.
The Franklin's ground squirrel is also known as the "whistle pig" because of the distinctive trill it makes.
The Illinois State Museum web page notes that the squirrel, which also goes by the name of spermophilus franklinii, usually lives in grass that is taller than lawn grass but short enough to see over when standing on hind feet.
The species is rare in Illinois because of the disappearance of the prairie.