Although pokemon riding has long been known around the world, from Ponyta cavalry in warfare to surfing across seas on water pokemon and the air on flying-types, nowhere is this tradition more developed than in Kalos, and Kalos teems with pokemon riders because of the Skiddo.
Skiddo are extremely friendly pokemon and grow quickly; it does not take them long after birth to grow large enough to carry an adult human rider. Although rarely used in warfare - except in logistics - they have carried trainers and their goods across Kalos for millennia, for they run far faster than humans even when carrying a rider's weight. Their speed allowed the Skiddo to connect the vast region of Kalos in a way which much of the world would have to wait for bicycles to approach, allowing for a large if decentralized state and regional networks of trade for virtually the entire history of Kalos. Skiddo, being grass pokemon, have little difficulty running through tall grass even in times of anarchy and nonexistent road maintenance, and are fast enough to escape most thieves and predators; in periods of fragmentation or anarchy, when no government could protect the roads, Skiddo proved instrumental in bringing Kalos back together.
Other terrain, such as spikes or snow, is impassable for Skiddo and humans alike, and in many parts of the world these obstacles serve as barriers which delineate one region from another, or human settlement from wilderness. But with Skiddo riding well-established in Kalos, it was only a modest conceptual leap to do the same with pokemon such as Rhyhorn and Mamoswine, and historians credit Skiddo for allowing the people of Kalos to master every type of terrain.