Mounts can be ridden to increase your movement speed when traveling around Sarnaut. Mounts also have a small amount of health that must be decreased by enemies' attacks before your mount disappears and you are dismounted.
Mounts can be fed special mount feed which will increase their movement speed and maximum health. It will also give them experience which will eventually increase their level. At higher levels mounts will move faster and have more health. However, a mount can only gain so much experience per day! Moving your mouse over the experience bar will warn you when your mount no longer gains experience when fed.
Mounts also have a rank that is represented by the stars in the top left-hand corner. The more stars there are, the higher the rank of the mount is. The rank of a mount is permanent, and higher ranked mounts has an increased movement speed and maximum health.
All of the mounts are stored in your stable. You can access your stable through your Character Info window, or by simply pressing "J". Your stable has a limited number of slots. One stable slot is usually given to your character when you acquire each new mount.