I heard someone make this comment, but I haven’t had much luck finding a confirmation or refutation of it, basically, that once a horse starts labor contractions, she can actually postpone the delivery for a number of hours.
Yes, it’s quite true – though you have the details a bit wrong.
A mare can postpone the start of labor, and will usually choose to postpone it until the mare is alone*. But once the labor contractions start, they can NOT be postponed. In fact, they are very rapid in horses – a birth hardly ever takes longer than 30 minutes, often much shorter. The foal will be standing & nursing within an hour, and when it’s a few hours old it will be able to follow along with the herd as it travels.
All of this – the postponing of birth, then the quick birth process, and the rapid development of the foal – are important survival traits for a nomadic herd animal that is a prey species.
The Horse Breeding section on Wiki (Horse breeding - Wikipedia) has some info on this.
- Mares are very ‘shy’ about this, even with people they know well. It’s a common story for horse owners to tell of carefully watching & waiting for hours night after night, then taking a 5-minute bathroom break, and coming back to find a newborn foal in the stall. Many horse breeders installed closed-circuit cameras in their foaling stalls as soon as these became reasonable in price. Thus they can watch the mare via the camera, and then hurry out to the barn when she actually goes into labor.
Even after reading the OP, I still somehow thought this was about the Pony Express.