Despite their dense coat protecting down to -40°C, what is often the primary limitation for yaks?

The availability of sufficient grazing in the extremely arid high steppes.

Yaks possess an extraordinary adaptation to cold, evidenced by their dense coat capable of providing protection even when temperatures plummet to -40°C. This superior cold tolerance means that the cold itself is generally not the limiting factor for their survival or distribution. Instead, the key constraint lies in sustaining their massive dietary needs within their ecological niche. The high steppes where they reside are often extremely arid, meaning that finding enough forage—sufficient grazing material—becomes the crucial bottleneck that dictates where they can thrive, even more so than surviving the intense cold.