Since November 1861, later accounts often distorted the variety and number of horses used by the Pony Express. The horses chosen depended greatly on region: fleet-footed thoroughbreds worked well on the central prairies, while half-broken California mustangs provided the strength and endurance needed for the arid deserts and rugged mountain ranges of the West. Alexander Majors, one of the three founders of the Central Overland California and Pike's Peak Express Company's Pony Express, selected the California mustang for those qualities and described it as alert and energetic as its riders. Because more than 100 stations were spread along the route, enough relay horses had to be kept to meet the system's demands. As the company prepared to begin service, it estimated that about 75 horses would be needed to make the nearly 2,000-mile trip from Missouri to California, yet a little more than two months before the first riders departed from St. Joseph and Sacramento, Russell, Majors, and Waddell began buying 500 of the best horses available, paying as much as $200 each for some, and one advertisement sought 200 gray mares four to seven years old, no more than fifteen hands high, well broken to the saddle, and sound. A modern horse in good condition might gallop five to eight miles on flat ground, and over the Sierra Nevada a horse and rider might cover five miles. Pony Express mustangs could travel about 10 miles an hour and at times gallop as fast as 25 miles per hour, though the distance they could go before exhaustion varied with heat, health, and water. Skilled riders kept a steady pace and usually galloped only to escape danger, and despite the difficulty of riding half-broken mustangs, riders believed that in a race for life such mounts could leave danger far behind. Mark Twain later wrote of about eighty riders in the saddle night and day between Missouri and California, forty going east and forty west, with four hundred horses at work daily, and in 1901 farrier and station keeper Levi Hansel recalled that shoeing the half-wild California mustangs at Seneca, Kansas, could take half a day for a single horse.