These are just two of the wild horses for which Cumberland Island is known. Some reports have as many as 150 horses, with an assumption that there are more than have actually been counted.
The horses are not very scared of visitors, but there are warnings not to touch them, as they are still wild. They’re not under veterinary care, and so “survival of the fittest” is what keeps the herd in pretty good condition. I saw some that looked like they had battle wounds, and they certainly were not groomed; however, considering the hostile environment of heat, scrub brush, mosquitoes, etc. that they live in, they looked pretty healthy.