Zandalari hunters automatically know how to tame Direhorns. Hunters of other races must learn the skill from an Ancient Tome of Dinomancy which is a rare drop from Zandalari Dinomancers on the Isle of Giants in Pandaria. This skill is NOT account-wide.
4 possible appearances:
Location & Notes:
Located in Passage of Time, Thaldraszus. Found on a shelf along the cliff just south of Tyrhold.