“It isn't every day that one can see a group of cowhands attempt to rope a dinosaur,” comments Ray Harryhausen on this wonderful monster-western in which a prehistoric reptile, Gwangi, is captured in his lair by a circus owner, and then escapes to the streets. “(We) all felt strongly that the period should take place about 1900, as modernization would simply present many cliché problems in disposing of Gwangi with present-day weapons....”
The Valley of Gwangi had its inception in 1942, to be produced by Willis O'Brien (Harryhausen's “mentor,” who used Dimensional animation as far back as 1925 in Lost World), but was abandoned by RKO after a vast amount of preparation had already been done (much of which has since been lost). This Gwangi (shot in Spain) includes a scene in which a pterodactyl plucks a man from a running horse, an elephant battle, and Gwangi's fight with a Styracosaurus. But the highlight is the sequence in which Gwangi defies the cowboys. Harryhausen writes (in “Film Fantasy Scrapbook”), “The timing of a scene such as this requires the utmost precision in eyelines and positions.... (It) took over five months before the animation camera....”