On Marc Singer's first day of filming, Billy Jayne (at the time his last name was Jacoby) was filming the scene where young Dar first learns that he could control animals. The bear happened to be a Russian bear, and the only bear working in Hollywood at the time. As soon as he came out, the bear broke loose and attacked his handler, sending the rest of the crew fleeing into nearby vehicles for safety. As soon as the bear was recaptured and the handler was carried off for medical attention, the crew turned and told Marc that they were ready to film his scene.
According to director Don Coscarelli, the original camera negative for this film is lost. Contrary to standard practices, it was stored in a private house which was sold, and it is not known what happened to the cans which housed the negative. Coscarelli has asked the public for help.
The eagle often refused to fly on cue. To shoot footage of it in the air, it was dropped from a trapdoor in a hot air balloon.
Producer Dino De Laurentiis liked the movie and offered Don Coscarelli to direct Conan the Destroyer (1984). Coscarelli declined because he thought the script was bad.