The Giraffidae is a still extant family, consisting of the Okapi and giraffes, but also of many extinct ancestors that existed all the way back to the Miocene epoch. Most species were (fairly) large in body size and had elongated necks and legs. They were strictly herbivorous, mostly browsing on leaves from bushes and trees. They inhabited both dense forests and (semi)open landscapes.
Distribution & Fossil evidence
Fossils of Giraffids have been found in many places on Eurasia and Africa. They probably evolved from small, Chevrotain-like species during the Early Miocene and eventually the evolutionary branch split at about 16 million years ago. From here, the neck vertebrae started to elongate in the branch that would result into the giraffes and shorten in the branch that would result into the Okapi.
There are many species of Giraffids known to science and many of them were fairly large in size.