New Studies on the Gaits Displayed by Miocene, Pliocene, and Pleistocene Fossil Horse Trackways

Abstract

The authors here apply a refined methodology to determine the gaits of fossil equids. Miocene trackways of Cremohipparion near Jumilla, Spain, contain three sets of tracks of equids trotting at around 2.9–3.4 m/s, crossed by another three sets of tracks of perhaps younger equids at play galloping at around 5.2–5.6 m/s. Other Miocene trackways include three sets of Hippotherium near Osoppo, Italy, galloping at around 6.2–6.5 m/s, and one of Scaphohippus from Barstow, California, in the United States, likely engaged in a rack (or less likely a trot) at 2.1 m/s. Pliocene trackways include one Hipparion near Elche, Spain, trotting at around 3.5 m/s, and three trackways of Eurygnathohippus from Laetoli, Tanzania, of equids racking (with one perhaps engaged in a running walk) at around 2.1–3.1 m/s, including tracks of what is likely a foal being supervised by its mare. Finally, a Pleistocene trackway of Equus near Cardston, Alberta, Canada, shows a horse in a gallop at around 6.6 m/s. Hence, Miocene to Pleistocene fossil trackways reveal that equids in the past possessed standard gaits (trot, gallop) as well as alternative lateral gaits (rack), and had similar herding behaviors found in modern horses today.