I love horses. I have a rather special fondness for the Icelandic horse as I am part Icelandic but also because these are the horses the Vikings used. Not the huge terrifying animals that go together with the ridiculous huge terrifying image of Vikings. Icelandic horses are small, cute, intelligent and tough. From the early steppe breeds, I think. In Iceland, if you take one out you cannot bring it back in. And, I think, vice versa. They are very careful about keeping the breed stable.
Humans could learn a lot about human breed stability from this method .