The horses were brought to Cumberland by humans over time -- they are not indigenous to the island and are descended from domesticated animals. This is why they are considered feral, rather than wild.
Between 125 to 175 wild horses roam Cumberland Island ... the are wild and adapted to the environment. These animals have been part of the island since 1742, when Spanish soldiers released ...
Visitors can glimpse some of the numerous plant and animal species that reside on the island and ... Read more about Commercial Spaceports Could Threaten Canaveral and Cumberland Island NPCA at Work ...