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Paleontology

Luzia living with the sloths

The huge South American mammals were contemporaries of the oldest human fossil of the Americas

An old suspicion has now been confirmed: Luzia and the enormous ground sloths, the South American “elephants”, were contemporaries and occupied the same piece of land. The name of the woman is in reference to the fragment of the oldest human skeleton found in the Americas, the skull f the young woman who lived some eleven thousand years ago, and was found in the mining region of Lagoa Santa, rich in pre-historic sites.

The animal, the ground version and an improvement on the current sloths that live in the trees, is possibly the most spectacular of the extinct animals that made up the megafauna of this portion of the south of the continent. The doubt about the coexistence of man with these hairy quadrupeds – who, depending on the species, could weigh up to five tons and reached six meters in total length – has been removed with the release, in April, of the result of a carbon-14 test to which was submitted a fragment of the rib of a ground sloth unearthed in the surroundings of Lagoa Santa, of the species Catonyx cuvieri, one of the thirteen identified in Brazil up until now.

“The examination showed that the sloth inhabited that area some 9,990 years ago”, says the bioarcheologist Walter Neves, from the Institute of Biosciences of the University of São Paulo (IB-USP), who will send off the examination to the North American laboratory Beta Analytic. Neves is coordinating the FAPESP thematic project that is proposing a new theory for the occupation of the Americas.

Mammals of the order of the Xenarthra, which originated and developed in South America and whose representatives of today are restricted to three groups of animals – tree sloths, armadillos, and tropical anteaters -, the ground sloths, came about around about 50 million years ago. However, it is not known exactly when they went into extinction – if it was before or after the presence of man in this part of the continent.

With the result of the carbon-14 dating, it has been proven in an explicit manner, that the sloths still walked through the woodlands of Brazil, their habitat, some ten thousand years ago, consequently after the first registrations of human presence in the Americas. Shortly afterwards, the giant sloths and human beings must have had some degree of living together for some time. The hypothesis that the ground sloths and man had been together side by side in the State of Minas Gerais was brought up in the middle of the 19th century by the Danish naturalist Peter Lund, who made lots of excavations in Lagoa Santa and found fossils of these large animals.

During the last decade, the paleontologist Cástor Cartelle, from the Federal University of Minas Gerais (UFMG), has also been defending this thesis, long before the result of the carbon dating test was ready. “We have the bones of sloths with marks of cuts that must have been made by humans”, says Cartelle. Shortly, new cabon-14 dating tests will be ready, carried out on the bones of other species of sloths rescued from the soil in Minas Gerais, thus increasing the evidence of the living together between humans and this prodigious animal.

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