Researchers at the University of Florida reported in 2005 that the Ground Sloth, a species of large-bodied mammal believed to have died out during the megafaunal extinctions, lived until only 5,000 years ago and may have died out as a result of human predation, rather than climate change.
In 2005, University of Florida researcher David Steadman reported in the Proceedings of the National Academy of Sciences (PNAS) that evidence of the existence several species of giant sloth has been found in the West Indian islands of Cuba and Hispaniola as recently as 4,400 years ago, about the time of the first human occupation of the area. Nineteen different species of sloths once roamed the Americas, but they were previously thought to have died out approximately 11,000 years ago. Steadman argues that the coincidence of timing is strong circumstantial evidence that while climate change may have decimated the population, human predation assisted the extinction of ground sloth in the Americas.
Megafaunal Extinctions and the Ground Sloth
Animal extinctions are a fact of the earth’s history, having taken place at numerous times over the millennia. Best known to the public are the dinosaur extinctions, which probably took place as a result of large-scale climate change which may have come about because of a meteor collision. Toward the end of the Pleistocene, between about 40,000 and 10,000 years ago, at least 85 genera of large-bodied mammals went extinct, including woolly rhinoceros and giant deer in Eurasia; saber-toothed tigers and woolly mammoths in North America; giant kangaroos in Australia; and some species of giant bovids in Africa. More recently, animal species extinctions have included passenger pigeon and dodoes. The widespread disappearances of these animals are not merely academic curiosities, of course; if other species can go extinct, perhaps human kind can do the same. Therefore, the reasons for faunal extinctions are of importance to our continued occupation of this planet.
The American continents have been the frequent target for investigations concerning megafaunal extinctions, in part because the Americas were the last big land mass occupied by the human race. The two most prominent reasons for extinctions in the Americas have included climate change at the end of the Ice Age, and interaction with humans, consisting of some combination of hunting, habitat destruction, and disease.
Ground Sloth for Dinner?
Although evidence of humans eating ground sloth has not been found to date, Steadman's research suggests that it may have occurred. It will be interesting to see if evidence does turn up eventually, particularly if butchering techniques are identified. While Steadman’s research certainly provides additional light to the continued study of megafaunal extinctions, most researchers would agree that the reasons for the disappearance of so many animals in so many different places over so many thousands of years are complex, and cannot be attributed solely to human predation.
Sources and Further Information
Steadman, David W., et al. 2005 Asynchronous extinction of late Quaternary sloths on continents and islands. Proceedings of the National Academy of Sciences 102(33):11763-11768.
