The hot springs of discord

In the centre of the island of Honshu, Japan, temperatures can fall to -20 °C in winter. To cope with this bitter cold, the Japanese macaques of Jigokudani have taken to bathing in the natural hot springs that have made the place famous. However, of the two hundred monkeys that make up this population, only about forty enjoy this privilege. When an individual not belonging to this dominant caste attempts to enter the pools, like this macaque here seen face-on, they are violently repelled. For ethologists, the Jigokudani site offers an opportunity to study conflicts within animal societies and the alliances that such tensions are likely to engender.