i believe the log fences in the pictures were already in place when gary and i got to great adventure. their job was to keep the elephants and rhinos contained in their areas. they held up well considering these large animals used them as scratchers and did not give in to their weight. when you make the long turn around the pond, about halfway in the turn, look right and uphill you'll see two gates up there. those lead to the elephant- rhino barn. the one on the left is the rhino side and the other is the elephant side. up that hill is two seperate paddocks for the animals to wander in while in the off season so the barn can be cleaned out. with nearly 30 elephants and 16 rhinos they can really make a mess. some of the animals did pick on others of their own species, that's why there is two paddocks, didn't want the large rhinos picking on the small elephants. i'm assuming those fences came down when all the animals grew to full size and that type fence wouldn't contain them anymore. back in the early, early 70's at a park in mesquite texas called world of animals the rhino section had a cable fence that the rhinos used as rubbing posts and ended up with notches worn into their horns. these rhinos were the 6 largest at great adventure at the time the park opened in 74 and could be identified by their horns from a pretty good distance. i hope that answers your question.