From 1829 to 1848, the Old Spanish Trail was a heavily used trade route connecting the Spanish-speaking communities of northern New Mexico with those in southern California. Pack trains of 100 or more mules, their packsaddles bulging with woolen goods woven in New Mexico, made annual treks between Santa Fe and Los Angeles. New Mexican traders bartered these goods for horses and mules and drove large herds back to Santa Fe. Over time, the trail also became the primary route for trappers, explorers, prospectors, and outlaws crossing the Intermountain West. American Indians witnessed the pack trains and left images pecked in rock. Mule packers, or Arrieros, were responsible for the woolen goods of many families, which represented an entire year's income, and mules were valued for their strength, endurance, ability to fare better than horses where water was scarce and forage poor, and their tough small hoofs that withstood rocky, boulder-strewn terrain.