Horse' legs evolved for travel, not speed

[Still Waters]

Palaeobiologists from the University of Bristol and Howard University have uncovered new evidence that suggests that horses' legs have adapted over time to be optimised for endurance travel, rather than speed.

The ancestors of horses (including asses and zebras) had three toes on each foot. Because only single-toed (monodactyl) forms survive today this anatomy has been perceived as a superior evolutionary outcome, enabling horses to outrun predators.

But our interpretation of equine evolution may be biased by our own history with horses: performance at the racetrack has been less important for human history than the endurance of horses at slower speeds, and such endurance may have been the critical factor in horse evolution.

https://phys.org/news/2019-04-toe-horse-legs-evolved.html