ABC canceled the series in 1994, which caused the Children's Television Workshop to plan its own TV channel so that it would not have to rely on other companies to air its shows.

Whenever a situation in modern times involves physics principles, Phil remembers when a similar event occurred long ago in the prehistoric valley of Woollyville with his fellow mammoths and his Cro-Magnon friend Cro, who lived with a family of Neanderthals.

The show's (and lead character's) name is an Occitan word for "cave"; it alludes to Cro-Magnon, the location in France where the earliest anatomically modern humans were first discovered.

Even though the show received high ratings and drew the largest audience in its time slot,[8] ABC cancelled the series after two seasons.

In response to the cancellation, the Children's Television Workshop started planning its own TV channel where it could air Cro as well as other shows from its library.

The CTW's senior Vice President, Gary Knell, said that "the lesson for us was that we can't rely entirely on other channels to put on programs which are educational as well as entertaining.