LONDON, March 2 (Xinhua) -- Researchers have discovered the world's oldest known figurative tattoos on two 5,000-year-old mummies from Egypt, according to a latest study.

The illustrations were a wild bull and a Barbary sheep on the upper-arm of a male mummy, and an S-shaped motif on the upper arm and shoulder of a female.

The findings pushed back evidence for the practice in Africa by 1,000years, and overturned the previous belief that only females wore tatoos in the ancient past for fertility or even erotic reasons.

The two mummies were found in Gebelein in the southern part of Upper Egypt about 100 years ago. Earlier researches indicate that they lived between 3,351 and 3,017 BC.

Preserved and exhibited in the British Museum, the tatoos on the male mummy were thought to be unimportant smudges until infrared scans revealed that they were tattoos of two slightly overlapping horned animals. They may have been worn as symbols of power and strength.

According to previous researches, the male mummy had probably died of murder with an apparent stab wound in his back.

Before the latest discovery, the oldest surviving examples were the tattoos on the Alpine mummy known as Otzi, who is thought to have lived between 3,370 and 3,100 BC. But his tattoos are vertical or horizontal lines, rather than figurative ones.

The discovery has been published in the Britain-based Journal of Archaeological Science.