The studio described the movie as a "pre-historic themed 3D computer-generated animated comedy adventure."
Cage is to play a caveman, the leader and protector of his family, while Reynolds will portray a nomad, an outsider whose new ideas challenge the patriarch's authority.
"We are thrilled that Nicolas Cage and Ryan Reynolds are lending their considerable talents to 'The Croods' and know that they will both bring a perfect blend of humor, enthusiasm and emotion to their lead roles," Bill Damaschke, co-president of production for DreamWorks Animation, said in a statement Thursday. "Our filmmakers are creating an amazing world that is full of fascinating characters, creatures and stunning environments that is truly unlike anything we've done before at DreamWorks Animation."
"The Croods" is set for release on March 30, 2012.