The precise ancestor of the okapi is still a little hazy. However, we do know that the okapi and the giraffe came from a common ancestory. This ancestor is called palaeotragus. It was believed to have a large body and a short neck and roamed throughout Europe and Asia. However, as it began to migrate to Africa, its current body couldn't thrive in the extreme heat or dense forest, and eventually this species died off.
Before the Palaeotragus died off it split into two new species. One being the giraffe of the savannah, and the other being the elusive okapi of the dense rainforest.
The Okapi has adapted in a myriad of ways from its late ancestor the palaeotragus. Due to its environment of the dense Ituri rainforest, it's coat is adapted to be oily, allowing the rain to slide, so to speak, right off it's back.
