Early-born domestic foals might have a cool start in life, with chilly winds and even snow welcoming them into the world. But there appears to be a payoff for those rough few months: Researchers in the Czech Republic have determined that the season’s older weanlings become—and tend to stay—more dominant in the social hierarchy.

The team found that one of the most important factors in determining a domestic weanling’s dominance level was his age, said Martina Komárková, PhD, of the Institute of Animal Science’s Department of Ethology, in Prague-Uhríneves. They observed 66 Kladruber (a breed of Czech sport horse) mare and foal pairs in eight herds over two foaling and weaning seasons, and four of the resulting herds of foals when they were three years old.

Dominant mares can be more aggressive to the foals of lower-ranking mares, and they can even help their own foals win a conflict with another foal, Komárková said. Because foals are capable of learning from their mothers, it seemed logical that the foals would learn dominance from them, as well. However, at least in modern domestic settings, that does not appear to be the case, she said.

“This doesn’t mean that foals can’t learn hierarchy status in other (more natural) situations,” said Komárková. “Foals observe their mothers (and, in nature, their fathers, too), and they learn behavioral schemes which they apply later in life. In our study, we suggest that the early abrupt weaning may disrupt the learning process.”

In standard breeding programs, handlers wean foals from their