The part that can be measured
Nathaniel Dominy, an anthropologist at Dartmouth College, and Catherine Hobaiter, a primatologist at the University of St Andrews, used spectrometry on twelve animal specimens from the American Museum of Natural History and measured the wavelengths of light reflected from baboon fur and ibis feathers. The species are the sacred baboon Papio hamadryas, the sacred ibis Threskiornis aethiopicus and the olive baboon Papio anubis. The reported result is that the reflected wavelengths are nearly identical to moonlight. The study was published online in the journal Time and Mind on 14 July 2026.[1]
It is worth recalling why the question existed. The moon god Thoth is represented by two animals that resemble each other not at all: a monkey and a bird. No visible property binding both to the same god was found for a long time. Now an instrument offers a candidate answer to a three-thousand-year-old question of iconography: what unites them is their coloration.[1]
The part that cannot
There are two propositions here and only one was measured. That the wavelengths reflected by fur and feathers are nearly identical to moonlight is a physical fact. That the ancient Egyptians chose these animals because of that resemblance is an inference no spectrometer reaches. A plainer reading also remains available: the list of animals held sacred was long, and in a long list two members may overlap in coloration by chance. The authors keep that caution, offering the interpretation as what may explain the connection and acknowledging that opportunities to understand these minds are rare.[1]
Something does change, though, and it is not the theology. Until now a question of iconography was answered with texts, reliefs and tomb paintings; now an instrument joins the list. That the study was done jointly by an anthropologist and a primatologist is no accident either: answering the question required reading both the animal itself and the culture that made it sacred. This is a widening of what counts as evidence, and a widened repertoire does not make an explanation proven.[1]
The question that stays
The difference between one striking overlap and a pattern is something that can be counted. If other pairings of animals held sacred are measured the same way and a similar match in coloration appears, the chance reading weakens; if none appears, this pairing stands alone, and that is an answer too. The measurement can tell us which wavelengths the animals reflect. The mind that chose them we still read only from the pictures it left, and where those pictures fall silent, staying cautious is the condition of curiosity.[1]