From an account by Spanish priest Pedro Simón of an expedition led by Luis Alonso de Lugo against the Tairona Indians of Colombia, 1535:

At dawn, as they lay hidden in the cornfields which surrounded the village, awaiting the moment to attack, they heard an ass bray. They knew that the Indians did not possess such animals, and did not believe that an ass could have climbed the high crags which barred the way from the coast. … When the place had been pacified and looted, they enquired about the ass … The Indians said that it had come in a ship, which had been wrecked on the coast. … They had killed those of the ship’s company who got ashore, but had kept the ass, and had carried it up into the mountains, trussed with ropes and slung between two poles, along with all the other loot they found in the ship. … So our soldiers, deeming it inappropriate and contrary to native custom that such articles should be in the hands of Indians, collected them all up, along with everything else that took their fancy, including the ass, and took it back to the coast. But the trails were rough, more suited to cats than men, and the descent was as hard as the ascent had been, so they made the Indians carry the donkey down just as they had brought it up; and very useful it turned out to be. Surely, as the first of its race to penetrate those mountains, it deserved to be numbered among the conquistadores. It served in other entradas later, and finally in the expedition which Hernando de Quesada, brother and deputy of Gonzalo Jiménez de Quesada the discoverer, led in search of El Dorado. It was ridden by Fray Vicente Requejada of the Order of Saint Augustine. … The ass served the friar well until, on the return march, they all ran out of food and, in the extremities of hunger, killed it for food. They left not a scrap of it. They collected its blood, made sausages of its guts, and even devoured its hide, well boiled. It had served them well in life, and served them better still in death, by its timely rescue from starvation; a salutary reminder of the hardships which in those days were the daily lot of discoverers.

See An Ass Cast Away and Hoof Positive.