On June 6, 1800, nearly a year into his scientific journey through South America, Alexander von Humboldt arrived at a mission on the Orinoco River called La Concepción de Uruana. It was a stunning site. The village sat at the foot of granite mountains, amidst huge pillars of stone that rose above the forest. Weeks before, Humboldt had seen mysterious etchings on the summits of such rocks—painted, the natives told him, by ancestors carried up there by the waters of a great flood.
Although weakened by bouts of fever and hunger, Humboldt was in fine spirits. In the preceding months he had watched the Leonid meteor shower fill the sky, experienced his first earthquake, and confirmed the communication of the Orinoco and the Amazon rivers through the Casiquiare Canal. He had collected electric eels and watched the dissection of a manatee. If at times the mosquitoes were so thick as to obscure the horizon and prevent his reckoning of latitude, or if other times ant hordes filled his canoe, he pushed on, spurred, he wrote, by an uncertain longing “for what is distant and unknown.”
Humboldt and his botanist companion Aimé Bonpland (and Indian servants, and pressed plants, and jars of preserving spirits, and a chattering menagerie of birds and monkeys in cages on his boats) stayed at Uruana for only one day, conversing with the missionary Fray Ramon Bueno and visiting the Otomac villagers. For all of nature’s splendors, it was the people of Uruana that most caught Humboldt’s attention: “a tribe in the rudest state,” “considered dirty even by their neighbors,” “ugly, savage, vindictive, and passionately fond of fermented liquors,” and yet presenting “one of the most extraordinary physiological phenomena” Humboldt had ever seen. The Otomacs ate earth, “a prodigious quantity” of it. During the two to three months of the rainy season, when the high and turbulent waters of the river made fishing difficult, they claimed to eat nothing but.