They weren’t on the continents, but scattered through the islands of the Caribbean. South America’s ground sloths, such the enormous Eremotherium, soon followed – the youngest dung and tissue samples found on the continent date between 10,600 and 10,200 years ago.īut for another 5,000 years, ground sloths survived. While Steadman and colleagues stressed that the dates represent “last appearance dates” rather than actual time of species death, the youngest known sloth remains from North America date to about 11,000 years ago. Megalonyx and other giants from North America were some of the first to go. They were one of the great success stories of the Ice Age – with 19 genera ranging through South, Central, and North America, as well as Caribbean islands at the end of the Pleistocene – but, as reported by paleontologist David Steadman and colleagues in a 2005 study, 90% of the existing Ice Age sloths disappeared within the last 11,000 years. Extinction is a process, not a single fell swoop.Ĭonsider the times when the giant ground sloths disappeared. Should a species be considered extinct when its very last member perishes, or when the population sinks below a level from which they can recover? And in these fading families, should the explanation for extinction be the cause of death of the last individual, or do we assemble a more complex picture that considers factors that made the population vulnerable in the first place? Both science and storytelling influence our answers to these questions, but one thing is abundantly clear. They very last of their kind, both protected and made vulnerable by life on islands, were still shuffling 4,200 years ago.Ĭalling the time of death for any species or lineage is always complicated by definitions and details. The shaggy, ground-dwelling sloths that inhabited almost the entire span of the New World didn’t all topple over at once. It’s nice and neat, falling just after the close of the last Ice Age and during a time when humans were spreading to new continents. That’s the oft-repeated cutoff date for when much of the world’s Ice Age megafauna – from mastodons to Megatherium – faded away. When did the last of the ground sloths disappear? The standard answer is “about 10,000 years ago”.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |