[2] The youngest species date to the Early Pleistocene, becoming extinct following the arrives of modern equines of the genus Equus to the Old World.

[3] Hipparionines varied widely in size, with the smallest species like Hipparion periafricanum having a body mass of only 23 kilograms (51 lb), considerably smaller than living equines,[4] while the largest species had body masses over 300 kilograms (660 lb).

[5] In the Old World hipparionins were initially browsers and mixed feeders (both browsing and grazing), over time there was increasing proportion of pure grazers, though the groups ecology remained diverse, with mixed feeding being the dominant ecology during the Pliocene.

[2] Hipparionins in the western Mediterranean during the Vallesian and Turolian exhibited noticeable niche partitioning, with smaller forms being mixed feeders while larger species had more grazing diets.

In contrast, contemporaneous eastern Mediterranean hipparionins did not exhibit such niche partitioning.