The first paleontological dig in the Americas

The first known Europeans in the New World to see fossils of large land animals were Hernán Cortés and his lieutenants. In the fall of 1519 they began their march inland to the Aztec capital of Tenochtitlan. Their path over the Sierra Madre Mountains led through the territory of Tlaxcala. Tlaxcala was one of the last remaining Nahua states to remain free of Aztec rule and its leaders had no intention of letting anyone's army enter their territory. An army was sent to stop the invaders. Although the Tlaxcalans had an opportunity to destroy the Spanish force, internal politics of the state led them to accept an offer of peace from Cortés. While the Spanish rested in Tlaxcala, the leaders of the state made every effort to curry favor and impress the strangers. The Spanish were fed and entertained. The leading houses allowed their daughters to be baptized. They promised an army to aid Cortés in his assault on Tenochtitlan.

At some point during the three weeks the Spanish stayed in Tlaxcala, a group of Spaniards began to question their hosts about their history. Bernal Díaz del Castillo, who wrote a history of the campaign described their answer. 

They said that their ancestors had told them, that in times past there had lived among them men and women of giant size with huge bones, and because they were very bad people of evil manners that they had fought with them and killed them, and those of them who remained died off. So that we could see how huge and tall these people had been they brought us a leg bone of one of them which was very thick and the height of a man of ordinary stature, and that was the bone from the hip to the knee. I measured myself against it and it was as tall as I am although I am of fair size.

 The Spanish helped themselves to the bone and sent it to the king on the first treasure ship. The bones of both Columbian mammoths and American mastodons have been excavated in that part of Mexico, but a bone as long as the one Díaz described probably came from an earlier mastodon species such as Rynochotherium tlascalae. In researching her book Fossil Legends of the First Americans, Adrienne Mayor went searching for this femur. Although museum officials in Spain couldn't identify that specific bone, they didn't exactly rule out its being there. The records for those years are just too sparse to be sure. It very well might be sitting, unlabeled, in a warehouse somewhere in Madrid.

Díaz wasn't the only Spaniard to report on the presence of large bones and legends of ancient giants. Cortés himself had a collection of bones at his estate. Later travelers, José de Acosta and Antonio Hererra y Tordesillas, also recorded the Tlaxcala legend and were shown giant teeth and bones. However, the most interesting report didn't come from Mexico, it came from Ecuador.

The conquest of the Inca Empire was nowhere near as easy as that of the Aztecs. For almost forty years, the Viceroyalty of Peru was plagued by civil wars and uprisings—not to mention actual plagues—among both the indigenous populations and their Spanish conquerors. In the 1540s, two very different men were thrust into the chaos. One was a soldier, Pedro Cieza de Léon, and the other a clerk, Agustin de Zárate. What they had in common was a strong sense of curiosity for the natural world. Near Quito, they both recorded the same story told by the local population. Long ago, horrible, deformed giants arrived on the Santa Elena Peninsula from across the sea. They raped and murdered the coastal people and ate all the food in the area. The people were defeated in every attempt to fight the giants, until: 

All the natives declare (wrote Cieza) that God our Lord brought upon them a punishment in proportion to the enormity of their offence. While they were all together, engaged in their accursed [sodomy] a fearful and terrible fire came down from heaven with a great noise, out of the midst of which there issued a shining angel with a glittering sword, with which, at one blow, they were all killed, and the fire consumed them. There only remained a few bones and skulls, which God allowed to remain without being consumed by the fire, as a memorial of this punishment.

 An angel destroys the Santa Elena giants in the 1700, French edition of Zárate. Source.

 Neither Cieza nor Zárate was able to go to the peninsula to see the bones. Cieza heard from enough from Spaniards who had seen giants’ bones in other parts of the Americas to accept that the story must be true, though probably exaggerated. Zárate wrote that the story seemed too fantastic to believe until he heard of another Spaniard who had been to the peninsula. 

Withal, what the Indians told about these giants was not fully believed until, in the year 1543, when the captain Juan de Olmos, a native of Trujillo, was lieutenant governor at Puerto Viejo, he caused excavations to be made in the valley, having heard of these matters. They found ribs and bones so large that, if the heads had not appeared at the same time it would not have seemed credible [i.e., that the remains were] of human beings.

What Olmos did was quite advanced for his time. He could easily have ordered the natives to bring him a few bones. Instead, he went to the place where the bones had been reported and examined them in situ. He recovered the complete bones of an individual and tried to reconstruct what it might have been based on the knowledge and worldview that he had. Europeans at the time still firmly believed in giants. The first intellectual challenges to the belief in giant wouldn't happen until the next decade. The debate over the historical reality of giants would continue well into the Enlightenment two hundred years later. That the skeleton did not perfectly match the proportions of a human skeleton wasn't a problem. Giants, by definition, were monsters. That it looked heavy-limbed and twisted was to be expected.

Both the central highlands of Mexico and Ecuador have remained rich sites for proboscidean fossils. In 1802, Alexander von Humboldt collected giant bones in Ecuador and in Mexico which he identified as resembling the elephant of the Ohio country. He also mentioned that the local people called one of the locations the Field of Giants. Humboldt sent the bones to his colleague Georges Cuvier in Paris. In an 1806 paper, in which he coined the name Mastodonte for the genus that included the Ohio animal, Cuvier determined that Humboldt’s bones represented three separate mastodon species (one of which he named M. humboldtii) and a giant ground sloth. Since then, several other proboscideans have been identified in Central and South America (the exact number is in constant flux). Some look quite different from the familiar mammoth and mastodon from further north. Some had four tusks. Some had short, almost fang-like tusks. Most paleontologists who work in the area probably don't realize that Latin America paleontology long predates its Anglo American sibling. Most don't know that the field began with a few soldiers who took time off from their wars to look at the world around them and ask questions.