Less than 20 years ago, the only challenges for the 100 residents of the tiny island of Kakara, off southwest Japan, were the elements and ensuring the fishermen’s catch could get to market on time.

Today, the islanders are outnumbered three to one by wild boar who feast on their gardens and are becoming increasingly aggressive and territorial.

The problems facing the residents of Kakara are being repeated across Japan, with boar numbers exploding as rural populations decline.

Japan's rapidly ageing and shrinking population is part of the reason behind the increase in wild boar, as older rural populations die out, leaving towns and villages empty. Meanwhile, young people are also moving to the cities in search of work. The number of people with shotgun licenses has also fallen sharply in recent years.

And as the people leave, the boar are moving in.

The first boars apparently swam to Kakara, which covers a mere 1 square mile and sits between Fukuoka and Saga prefectures, but have been in hog heaven ever since.

They have found a place with no natural predators and plenty of crops, such as pumpkins and sweet potatoes, that the local people grow in their back gardens.