Men and women practise what is known as a “walking marriage” – an elegant term for what are essentially furtive, nocturnal hook-ups with lovers known as “axia”. A man’s hat hung on the door handle of a woman’s quarters is a sign to other men not to enter. These range from one-night stands to regular encounters that deepen into exclusive, life-long partnerships – and may or may not end in pregnancy. But couples never live together, and no one says, “I do”.

“For Mosuo women, an axia is often a pleasurable digression from the drudgery of everyday life, as well as a potential sperm donor,” says Waihong.

Women own and inherit property, sow crops in this agrarian society, and run the households – cooking, cleaning and child-rearing. The men provide strength, ploughing, building, repairing homes, slaughtering animals and helping with big familial decisions, although the final say is always with Grandmother. Although men have no paternal responsibilities – it is common for women not to know who the father of their children is, and there is no stigma attached to this – they have considerable responsibility as uncles to their sisters’ children. In fact, along with elderly maternal great-uncles, who are often the households’ second-in-charge, younger uncles are the pivotal male influence on children.