What early trade disadvantage did pre-columbian civilizations such as the maya, aztec, and inca have?

One disadvantage of Pre-Columbian civilisations is that they had no animals that could be used to carry things - such as donkeys or horses, so the goods could not be transported as well as in the Old World - those animals simply did not evolve in America or disappeared by that time. People often had to transport the goods they wanted to sell on their backs.