Long before the Chicago Cubs and famous pizza, Illinois was a marshland in a balmy and exotic tropical climate. That was 300 million years ago during a time when Illinois wasn’t Illinois, but part of a supercontinent called Pangea. A time when Illinois was inhabited by a monster ­ yes, a monster, among other unique and now extinct creatures.

Illinois 320 million years ago.
illustration by Alice Prickett

It may seem hard to believe, but at that time Illinois was located just a few degrees north of the equator and was covered with a mixture of swampy lands and warm, shallow seas. Just off the shore of this sea lived the Tully Monster ­ a mysterious creature whose fossils are said to predate dinosaur remains by at least 72 million years.

To this day, scientists are still unsure as to the kind of animal the Tully Monster was. The creature could be a relative of worms, snails or even something else, but no one knows for sure. However, scientists do agree that the Tully was a soft-bodied marine carnivore that grew to be as long as a foot in length. Its description may not be that of typical pop-culture monsters ­ big, hairy, enormous teeth ­ but it was a monster nonetheless … A monster that has baffled scientists since its discovery in the 1950s at a coal strip mine near Grundy County, Illinois.

Join us as we explore what the Tully Monster really was, how it lived and why it is now extinct.