Official description:
Cumberland Island Horse is one of the wild horses.
Tame this horse in order to age it, train it, take it for rides, and enter it into competitions. You can also ask other owners of a wild horse to help you progress faster. Help others in return and increase your horse's skills.
Once tamed, this horse will give you 10 passes each year until age 80. The reward can appear on any of the buttons for horse care when waking up.