Giraffidae

The artiodactyl family of Giraffidae contains the okapi (Okapiajohnstoni) and giraffe genera, which shared a common ancestor 11.5 million years ago. Based on the giraffe population structure and phylogenomic analysis, four separate giraffe lineages diverged 230–370 thousand years ago, suggesting there are four giraffe species. Giraffids can be challenging to image because of their size. Radiographs of distal limbs are diagnostic for multiple conditions, but radiographs or US of the thorax and proximal limbs may be limited by anatomic considerations or equipment and logistical constraints. The giraffe heart has relatively thick muscles of the left ventricle and interventricular walls. Female giraffids have a bicornate uterus and are nonseasonal breeders. Transabdominal pregnancy US in giraffids can be performed using a low frequency macroconvex probe with training either in an open chute or along a fence. Giraffids usually do not have a gallbladder.