They are smaller than normal warhorses and cannot bear the weight of the armor a warhorse usually wears. Dornishmen claim the mounts are able to run for a day and night and another day, and never tire.
In The Conquest of Dorne King Daeron I Targaryen remarked that the Dornish love their sand steeds equal to their children, and wrote that the Knight of Spottswood had his sand steeds stabled in his very own hall.
A Storm of Swords
A Feast for Crows
Nymeria Sand rides a golden sand steed to meet her uncle, Prince Doran Martell, en route from the Water Gardens to Sunspear. Tyene Sand works on an embroidery of Oberyn armored in red atop a sand steed.
The Winds of Winter
This information has thus far been released in a sample chapter for The Winds of Winter, and might therefore not be in finalized form. Keep in mind that the content as described below is still subject to change.