A wild bull, a Barbary sheep and S-shaped motifs discovered on two mummies in the British Museum have been revealed as the world’s earliest known figural tattoos.

Researchers say the discoveries on two naturally mummified bodies that date from between 3351 and 3017BC mean they will have to rewrite the story of tattooing.

Daniel Antoine, the curator of physical anthropology at the British Museum, said: “Incredibly, at over 5,000 years of age, they push back the evidence for tattooing in Africa by a millennium.”

The findings, published in the Journal of Archaeological Science, concern a mummified man and woman from Egypt’s predynastic period, the era before the country’s unification by the first pharaoh in 3100BC.

The male mummy, known as Gebelein Man A, is something of a gallery favourite. He is one of the best-preserved mummies in the world and has been on display almost continuously since his discovery around 100 years ago.

He is known to have had ginger hair; in 2012, it was revealed that he had probably been murdered, apparently stabbed in the back.

What had not been examined previously were some indistinct dark smudges on his upper right arm that have now been revealed as tattoos of a bull and of a sheep. They may have been worn as symbols of power and strength.

Before the discovery, archaeologists had thought tattoos were restricted to women.

On the female mummy, known as Gebelein Woman, researchers found a series of four small S-shaped motifs that were more difficult to interpret. They could be crooked staves or throw-sticks, batons or clappers used in ritual dance.

Tattoos were a part of many ancient cultures. Before the latest discoveries, the oldest surviving examples were mainly geometric tattoos on an Alpine mummy known as Ötzi the Iceman. He dates from the fourth millennium BC, so is approximately contemporary with the Gebelein mummies.

Antoine, one of the lead researchers on the paper, said use of CT scanning, radiocarbon dating and infrared imaging “has transformed our understanding of the Gebelein mummies. Only now are we gaining new insights into the lives of these remarkably preserved individuals.”