I cited Swedish explorer Erland Nordenskiold in a post last week and forgot to mention the role he played in one of the last great natural history adventures of the 19th century.
In 1895 a former merchant sea captain named Hermann Eberhardt, farming on the shores of a inlet called Ultima Esperanza (“Last Hope”) in southern Chile discovered a giant cave on his property. Inside he found a large fresh-looking skin covered with long reddish-gray hair and embedded with bean-sized bones. Scientists identified it as that of an extinct Mylodon ground sloth. Further excavations uncovered bones with bits of dried tissue still attached, plus evidence of human habitation.
Today we know the bones and skin were preserved by the climate inside the cave, but to Professor Florentino Ameghino of the Buenos Aires museum, the skin appeared fresh. He remembered a story a friend had told him of seeing a strange animal while exploring in the area. Ameghino linked the story and the skin to a legend of a large nocturnal beast local natives called iemisch, with giant claws it used to dig burrows where it slept during the day. Ameghino concluded the iemischwas a living Mylodon ground sloth. His announcement created a world-wide stir. (Ameghino, 1898)
Erland Nordenskiold was a voice of reason in the hullabaloo and conducted the first systematic excavation of the cave. However, publication of his study only added fuel to the fire. He determined the evidence of human habitation lay in a distinct horizon above and separate from the older lower horizon with its sloth bones, dung and dried grass.(Nordenskiold, 1900). Modern radiocarbon dating of the dung indicates the cave was occupied by sloths from about 13,500 years B.P. to 10,500 B.P. (Markgraf, 1985).
Others concluded from the large quantities of the dung and finely chopped “hay” that sloths had been kept captive inside the cave by natives fattening them for slaughter, behind the stone wall Nordenskiold had reported. Some even suggested the sloths had been domesticated (Allen, 1942). Today we know the sloth “corral” was merely fallen rock from the ceiling (Naish, 2005)
In 1900 the Daily Express sponsored an expedition to Patagonia to capture a living Mylodon. The venture was mismanaged however and the leader, HV Hesketh-Prichard, quit before reaching the cave. He dismissed the idea as a hoax (Hesketh-Prichard, 1902).
Nordenskiold offers us a lesson on the sloth project–finding three sloths in close proximity doesn’t make them a familyno matter how good it looks. Only careful excavation, painstaking attention to stratigraphy and detailed chemical analysis will do that. . . . Dave
Ameghino, F. 1898. An existing ground-sloth in Patagonia. Natural Science 13: 324-326.
Heuvelmans, B. 1995. On the Track of Unknown Animals. R. Garnett (transl.) Kegan Paul International.
Markgraf,V. 1985. Late Pleistocene faunal extinctions in southern Patagonia. Science 228: 1110-1112.
Naish, D. 2005. Fossils explained 51: Sloths. Geology Today 21: 232-238.
Nordenskjold E. 1900. La grotte de Glossotherium (Neomylodon) de Patagonia. Bulletin de la Societe Geologique de France: 29: 1216-1217.