Research last year revealed a gender bias toward male horses in key equestrian disciplines, with mares being stereotyped as moody or bossy.
Now, scientists have found that this preference for males appears to date back nearly 4000 years.
The work was led by paleogenomicist Antoine Fages at Paul Sabatier University in France.
For their research, Fages and his colleagues set out to unravel the roles that male and female horses played in the history of the human-horse relationship.
Their work was based on analysis of ancient DNA in the skeletal remains of 268 horses spread across Eurasia, dating back as far as 40,000 years, to determine the sex of each animal. The most recent remains dated to about 1300 years ago.
The horses, at sites sprinkled across Eurasia from Britain to Siberia, all had links to humans. Some had been deliberately buried, often in relation to human burials, while the remains of others were found among rubbish, most likely the victims of hunting.
The researchers found even sex ratios until around 3900 years years ago.
Fom then on, they found a striking over-representation of males, which was particularly obvious in human burials. Stallions (or geldings) were clearly more prized for sacrificial rituals, possibly because of symbolic attributes linked to masculinity, warfare, power, protection and strength, they said.
The research team said their findings suggest early horse hunters pursued both sexes equally.
But even after domestication by members of the Botai culture around 5500 years ago on the Eurasian steppe, the earliest horse herders managed males and females alike for more than a thousand years. The Botai were known to both hunt and manage horses in herds.
Then, gender bias became entrenched around the start of the Bronze Age to a startling degree. The study team identified three times more stallions than mares among the bones analysed.
This, they said, followed the emergence of gender inequalities in human societies.
“Our observations show that the emergence of a gendered vision of the world in the Bronze Age also extended to the domestic animal sphere,” they concluded.
“Whether this only applies to the horse, as the animal of prestige by excellence, or also extends to other domestic animals, such as dogs, pigs and cattle, remains to be investigated.”
The study team comprised Fages, Andaine Seguin-Orlando, Mietje Germonpré and Ludovic Orlando.
Horse males became over-represented in archaeological assemblages during the Bronze Age. Antoine Fages, Andaine Seguin-Orlando, Mietje Germonpré, Ludovic Orlando. Journal of Archaeological Science: Reports Volume 31, June 2020, 102364, https://doi.org/10.1016/j.jasrep.2020.102364