The Incas first had horses only after the Spanish arrived in Peru. Before that the Incas used the llama for transportation purposes. Since they did not have horses then, Inca's walked the trails with the llama as a companion. The Inca roads were used by people to relay messages, which were carried via books, a knotted cord called the quipu, and by memory. The trails were also used for the transportation of goods. The Inca system traverses the Andes mountains and reaches a height of 5,000m above the sea level. The trail begins in Ecuador, passing through Cusco and in what is now Tucuman, Argentina. The coastal trail, El Camino de la Costa, which is 4,000 km in length was linked with Camino Real by many other routes and ran parallel to the sea.
Horses originated on the North American continent. But during the last ice age (!5,000-10,000 years ago), the species migrated back to Asia over the Bering Strait ice bridge, and they disappeared from the Western Hemisphere. Not until the Spaniards arrived in the early 16th century did horses return to their ancestral grounds. Precolumbian people, including the Incas, did not have animals large enough to be ridden. Llamas -- called "the ship of the Andes"-- could only carry up to about 60 pounds, not an adult human's weight. So they were only used as pack animals. Consequently, there were no road per se in the Americas, only trails for llamas and humans, such as the famed Inca Trail leading to Macchu Picchu. Precolumbian people also did not develop the concept of a large wheeled vehicle with an axle strong enough to bear substantial weight. However, they did produce wheeled toys; an example is a small toy dog in the Rufino Tamayo Museum in Oaxaca, Mexico. North American Indians used dogs as pack animals and also fashioned travois: Two long poles attached to the dogs sides on one end, and meeting in a point at the other, with a hide platform stretched between for gear. Once horses were reintroduced, Indians quickly saw their advantage for hunting, transport, nd warfare, with the U.S. Great Plains peoples becoming the most adept horsemen and horse traders. One of the ways archaeologists date rock art is if horses are included in the images; if so, they are post-16th century.