When it comes to the fascination with exotic species, the ancient Egyptians seem to have got there first. Archaeologists working at a cemetery in Hierakonpolis, a thriving city by the Nile in the fourth millennium BC, have uncovered a zoo’s worth of skeletons of baboons, hippopotamuses, leopards, elephants and crocodiles. These were not pampered pets; the remains reveal scars from beatings and broken bones from tethering.

The rather cruel menageries of old have given way to modern zoos that prioritise conservation and welfare — but the propriety of keeping non-human primates in captivity is being questioned anew. Last week, London Zoo went into lockdown when a male gorilla escaped his enclosure. Kumbuka, a western lowland silverback, had managed to reach a secure keepers’ area and was tranquillised before being returned to his domain. Visitors later said he had seemed agitated beforehand.

It is a happier ending than that enjoyed by Harambe, a gorilla at Cincinnati Zoo, who was shot dead in May after a young boy fell into his enclosure. There are, incidentally, two earlier cases where gorillas have protected children in similar circumstances.