Some mares have a greater 'maternal instinct' than others. All mares with foals should have a certain baseline level of protectiveness and attention directed toward their foals. | Photo: iStock

A: This question opens up a lot of avenues to interesting equine behaviors. I can’t say for sure that your mare isn’t showing any maternal behaviors toward this Miniature. However, I would find it unlikely that she’s mistaking a mature, but very small, horse for a foal. Your mare just probably really likes this new horse. Perhaps she had no other buddies, or perhaps she didn’t really get along with other horses she was with. It would be good to carefully identify the specific behaviors she is showing and see if they correspond with actual maternal behaviors or just common social behaviors among cohorts.

Adult humans seem to find baby (both human and animal) features—such as big eyes, chubby cheeks, a large head, and a rounded body shape—very compelling. This is, theoretically, an adaptation so we have a strong nurturing instinct even for young not our own. The degree to which this is true in horses, as far as a mare generalizing her attachment to any other that has babyish features, I don’t know. However, we can look at other behaviors and see that, broadly, mares tend to show specific maternal attachments only toward their own foals.

Certainly some mares have a greater “maternal instinct” than others. All mares with foals should have a certain baseline level of protectiveness and attention directed toward their foals. But certainly there’s variation among mares in how permissive they are toward humans or other horses interacting with their foal, tolerance of the foal wandering about, and distance they’ll travel away from the foal