Irwin Allen followed up his well-received documentary The Sea Around Us with the equally entertaining Animal World. The film begins with a thumbnail history of life on earth, then shows the audience how ancient habits and instincts die hard. Willis O'Brien and Ray Harryhausen, the team responsible for the stop-motion animation in 1949's Mighty Joe Young, lavish their expertise on the film's opening dinosaur-battle sequence. The "actuality" footage is culled from 27 different countries, representing the handiwork of nearly 100 naturalists and filmmakers. Highlights include several life-and-death struggles in Africa, a battle between an eel and an octopus, and the birth of a starfish. After watching Animal World, one genuinely regrets that Irwin Allen abandoned the documentary form in favor of such TV silliness as Lost in Space and such cumbersome movie blockbusters as The Towering Inferno.