Egypt's Sacred Baboon Wears the Color of Moonlight

Run the silvery coat of a hamadryas baboon through a spectrometer, and the readout matches moonlight. The sacred ibis's white plumage matches it too. In ancient Egypt, those two different animals stood for one god.

The god was Thoth, who oversaw the moon, writing, wisdom and magic. Most Egyptian gods took a single animal form. Thoth took two, and scholars have long wondered why.

The ibis was the easier case. Its curved bill echoes a crescent moon, and its feathers come in black and white. Earlier work traced Thoth's Egyptian name to North African words for a bright or white thing and tied that to the bird's brilliant feathers. The baboon was harder to explain.

A team from Dartmouth and the University of St Andrews set the human eye aside, since people judge color through a cultural filter. They used spectroscopy, which measures the wavelengths of light a color gives off. The ibis and the baboon both came back matching moonlight. The findings, which appeared in the journal Time and Mind, support the idea that both animals were made divine because their coloring resembled moonlight.

The choices Egyptians made point the same way. Primatologist Catherine Hobaiter, who led the study, notes that Egyptians knew at least three kinds of ibis and picked the white one. They knew two baboon species, plus vervet and patas monkeys, and picked the silver-white baboon.

That still leaves the bigger puzzle. Most African cultures take a dim view of baboons, largely because they raid crops. Ancient Egypt may be the only culture that went past revering baboons and made them gods. Anthropologists and primatologists can't fully say why.

Across most of Africa, a baboon near the crops is a pest. In Egypt, the right shade of silver may have gotten one promoted to god.

Read the full story at University of St Andrews, July 23, 2026

Hot Take: Modern researchers didn't trust human eyes with color, so they brought a spectrometer. Egyptians went by eye, faced a lineup of at least seven birds and monkeys, and matched the machine twice.