InsideJapan News Network

Rhesus monkeys at a Japanese zoo have been put on a strict diet after some became so overweight they could not move around their enclosure.

The monkey's are a popular attraction at Ohama Park in western Japan and have received international media notoriety as a result of their obesity.

Park superintendent Syoji commented: "We don't really know the exact reason why the monkeys grew fat, but we reckon it's because the monkeys are not only fed once a day by us, but also because this park is open 24 hours a day to visitors, who throw food into the enclosure."

Zookeepers have halved the animals' calorie intake after some of the monkeys were found to be at least three times heavier than average, according to the Reuters.

In addition to the monkey island, Ohama Park also includes a sumo wrestling hall, a swimming pool and a baseball field.