It lived in North America during the Miocene and Pliocene epochs during the Hemingfordian to the end of Hemphillian from around 17.5 to 4.9 million years ago.

[7] Teleoceras went extinct in North America alongside Aphelops at the end of the Hemphillian, most likely due to rapid climate cooling, increased seasonality and expansion of C4 grasses, as isotopic evidence suggests that the uptake of C4 plants was far less than that in contemporary horses.

[9] Teleoceras has high crowned (hypsodont) molar teeth, which has historically led to suggestions that the species were grazers.

There is also a rarity of young adult males preserved at Ashfall, which may be accounted for if they formed bachelor herds away from females and dominant bulls.

Their skeletons show evidence of bone disease, ie hypertrophic pulmonary osteodystrophy (HPOD), as a result of lung failure from the fine volcanic ash.

[11] The greatest concentration of Ashfall fossils is housed in a building called the "Rhino Barn", due to the prevalence of T. major skeletons at the site, of which most were preserved in a nearly complete state.