With flashing red eyes and a swiveling head, Yuuji Ohta's robot wolf bares its white canines and lets out an array of ghastly growls. A matted coat of brown synthetic fur covers its life-size body.

This futuristic creature is part of everyday life for Ohta, president of a company that manufactures machine tools in rural northern Japan. While he started making mechanical wolves as a hobby, the side venture has become a serious business in recent years. As the country's human population declines, the number of boars, bears, deer, monkeys and other wildlife is rising, encroaching on areas where people live and work. This version of the robot wolf is stationary, but the next will be able to chase animals away.

Ohta's fake wolf illustrates a silver lining of Japan's demographic retreat — or the potential for a big missed opportunity. The country desperately needs to pour investment into robots and other technology that caters to its aging and diminishing population. The big question is whether Japan can wring out the advantages from the circumstances it faces.