Audio. Jaguars are the largest of South America's big cats. They once roamed from the southern tip of that continent north to the region surrounding the U.S.-Mexico border.Today significant numbers of jaguars are found only in remote regions of South and Central Americaâparticularly in the Amazon Basin.udio. Jaguars are the largest of South America's big cats. They once roamed from the southern tip of that continent north to the region surrounding the U.S.-Mexico border.