Llamas

The horse was unknown in South America before the Spanish arrived, so heavy loads were typically carried either by porters or by llamas. While llamas cannot carry such heavy loads as horses or mules (their weak backs also make them unsuitable as riding animals), their sure-footedness fits them perfectly for the steep and narrow mountain trails of the Andes, allowing them to travel over terrain that would be impassable to horses.

For more information, see:

Llamapaedia

Hattiesburg Zoo

Hanover Zoo

Philadelphia Zoo

Llama Market