The rapidly expanding deer and wild boar population in Japan is having a serious impact on the nation's agriculture and ecosystems. The population of deer was estimated at 3.25 million and that of wild boars at 880,000 across the country as of 2011. The government has proposed an amendment to the law on animal protection, calling for efforts to reduce the number of wild animals to appropriate levels. The challenge is how to secure the manpower and other resources to meet the targets.

The deer population has sharply increased as many of the nation's aging hunters have retired. The government also believes that their habitat has expanded as a widening area of Japan's farmland has been abandoned with the decline in the number of farmers and that changes in ecosystems due to global warming has reduced the number of deer that die of starvation in winter.

These animals' growing numbers have caused severe damage to agricultural production, which is estimated to reach ¥20 billion annually. Signs of the impact on ecosystems have also been found in many of Japan's national parks, where trees have withered after their bark was eaten by deer, alpine plants have been consumed and mudslides have taken place in areas where vegetation has been stripped away by foraging animals. To prevent further damage, these animal populations need to be controlled.