La vague sans précédent d’extinctions de grands mammifères durant les 66 millions dernières années est liée à nos ancêtres.
19 avril 2018
Homo sapiens, Néandertal et d’autres parents humains récents pourraient avoir commencé à chasser les espèces de grands mammifères de grandes tailles jusqu’à extinction au moins 90.000 ans plus tôt que prévu.
Elephant-dwarfing wooly mammoths, elephant-sized ground sloths and various saber-toothed cats highlighted the array of massive mammals roaming Earth between 2.6 million and 12,000 years ago. Prior research suggested that such large mammals began disappearing faster than their smaller counterparts — a phenomenon known as size-biased extinction — in Australia around 35,000 years ago.
With the help of emerging data from older fossil and geologic records, the new study estimated that this size-biased extinction started at least 125,000 years ago in Africa. By that point, the average African mammal was already 50 percent smaller than those on other continents, the study reported, despite the fact that larger landmasses can typically support larger mammals.
But as humans migrated out of Africa, other size-biased extinctions began occurring in regions and on timelines that coincide with known human migration patterns, the researchers found. Over time, the average body size of mammals on those other continents approached and then fell well below Africa’s. Mammals that survived during the span were generally far smaller than those that went extinct.
Unprecedented wave of large-mammal extinctions linked to ancient humans | Nebraska Today | University of Nebraska–Lincoln
L’article original provien du journal Science : Felisa A. Smith, Rosemary E. Elliott Smith, S. Kathleen Lyons, Jonathan L. Payne. Body size downgrading of mammals over the late Quaternary. Science, 2018