It was a lightly built, pony-like mammal of about 1.5 m (5 ft) long. Hyracodon's skull was large in comparison to the rest of the body. Hyracodon's dentition resembled that of later rhinoceroses, but it was a much smaller animal and differed very little in appearance from the primitive horses of which it was a contemporary (32-26 million years ago). It had a short, broad snout and its long, slender limbs had three digits. This small, fast-running creature was a close relative of the largest land mammal that ever lived, the 8 m (26 ft) tall Paraceratherium.