Heck horses are dun or grullo (a dun variant) in colour, with no white markings. The breed has primitive markings, including a dorsal stripe and horizontal striping on the legs. Heck horses generally stand between 12.2 and 13.2 hands (50 and 54 inches, 127 and 137 cm) tall. The head is large, the withers low, and the legs and hindquarters strong. The hooves are strong, often not needing shoeing. The gait of the Heck horse is high stepping, which makes them comfortable to ride and which is considered attractive while being driven. The breed is described as being calm, friendly, curious and intelligent, although very independent. The physical description of tarpans was very similar - strong, approximately the same height, and with the same coloration and primitive markings.