In Siberia, annual temperatures fluctuate between + and winter may last for 8 months. Yakutian horses are kept unstabled year-round, and in the roughly 800 years that they have been present in Siberia, they have evolved a range of remarkable
morphologic,
metabolic and
physiologic adaptations to this harsh environment. • While smaller than modern highly derived horse breeds, they are larger than other primitive horse breeds (
Bergmann's rule); at the same time they have a compact build with a stouter trunk and legs that are relatively short in proportion to the horse's size (
Allen's rule). • Their winter coat is extremely dense and reaches a hair length of . • Their metabolism adjusts to seasonal needs. In fall they accumulate large fat reserves, in winter the metabolic rate is lowered, and in spring they show an increased carbohydrate metabolism, making use of the freshly sprouting grass. • They show an increased production of
antifreezing compounds. • They may further avoid frostbite by reducing the volume of circulating blood during times of extreme cold, as indicated by an increased responsiveness of their genetic networks involved in
oxidative stress responses,
vasodilation, and
blood coagulation. Genetically they show indications of
convergent evolution with other inhabitants of the Far North like
mammoths regarding their adaptation to the extreme cold. == Uses ==