Do you ever worry about being out on the trail after dark? It's a legitimate concern; after all, if humans can't see well in low light, how well can a horse?

Researchers already know that horses have the physical equipment for scotopic (night) vision, with more rods than cones and a reflective structure in the retina. Experience tells us that they continue to graze, interact, and move about at night. Wild mustangs can even be seen running at full gallop over rough terrain while negotiating sagebrush, rocks, hills, and gullies with only starlight to guide them.