The answers may even help biologists eke out lessons about how modern elephants might cope as habitats shrink and hunting pressures rise. “How resilient were these populations - or not?” “How did these big herbivores respond to climatic shifts, both before and after humans arrived?” asks Hendrik Poinar, a geneticist and anthropologist at McMaster University in Hamilton, Canada. Scientists hope to better understand the extinct elephants’ role in ancient ecosystems. A recent analysis of the chemistry of European mammoth bones reveals that those animals probably struggled with dwindling food sources as the climate warmed, which probably hastened the animals’ demise.Įxcavating some of the last known sites where mammoths and humans coexisted points to how early Americans gathered around a kill, making the most of the giant carcass to feed themselves. Tiny scratches on the teeth of mastodons from North America suggest that they ate a surprisingly varied diet of grasses, twigs and other plants, depending on their environment. Scientists are exploring what plants these megaherbivores ate as they rambled across the landscape, and how they competed with other animals - including humans - as climate changed and the last ice age ended some 11,700 years ago.Ĭlues to these mysteries lie in ancient teeth and bones. Now, researchers are knitting together these scattered discoveries into a more coherent picture of the lives and deaths of mammoths and mastodons. These foot bones are from Ernie, a mastodon measuring 3.2 meters at the shoulder, the tallest ever found in North America. Scientists have found the remains of mastodons and their relatives, the mammoths, throughout the Northern Hemisphere - from huge tusks buried in the Alaskan permafrost to mummified baby mammoths in Siberia ( SN Online: 7/14/14). Excavators are working to dig up the rest of Ernie’s bones before this winter, with an eye to reassemble the ancient beast, the researchers reported in October in Albuquerque at a meeting of the Society of Vertebrate Paleontology.Įrnie is a jaw-dropping example of the ancient elephants that once roamed Earth. He would have dwarfed today’s large African elephants, which average up to six tons. The researchers emphasise that the pathway to extinction for the woolly mammoth was long and lasting, starting many millennia before the final extinction event.Ernie is still the biggest mastodon ever found in North America. "And shows that species extinctions are usually the result of complex interactions between threatening processes." "It also refutes a prevalent theory that climate change alone decimated woolly mammoth populations and that the role of humans was limited to hunters delivering the coup de grâce". "Our analyses strengthens and better resolves the case for human impacts as a driver of population declines and range collapses of megafauna in Eurasia during the late Pleistocene," he said. "Our finding of long-term persistence in Eurasia independently confirms recently published environmental DNA evidence that shows that woolly mammoths were roaming around Siberia 5,000 years ago," said Associate Professor Jeremey Austin from the University of Adelaide's Australian Centre for Ancient DNA.Īssociate Professor David Nogues-Bravo from the University of Copenhagen was a co-author of the study which is published in the journal Ecology Letters. The study also shows that woolly mammoths are likely to have survived in the Arctic for thousands of years longer than previously thought, existing in small areas of habitat with suitable climatic conditions and low densities of humans. However, until now it has been difficult to disentangle the exact roles that climate warming and human hunting had on its extinction," said Associate Professor Fordham. "We know that humans exploited woolly mammoths for meat, skins, bones and ivory. Signatures of past changes in the distribution and demography of woolly mammoths identified from fossils and ancient DNA show that people hastened the extinction of woolly mammoths by up to 4,000 years in some regions. "Using computer models, fossils and ancient DNA we have identified the very mechanisms and threats that were integral in the initial decline and later extinction of the woolly mammoth." "Our research shows that humans were a crucial and chronic driver of population declines of woolly mammoths, having an essential role in the timing and location of their extinction," said lead author Associate Professor Damien Fordham from the University of Adelaide's Environment Institute. An international team of scientists led by researchers from the University of Adelaide and University of Copenhagen, has revealed a 20,000-year pathway to extinction for the woolly mammoth.
0 Comments
Leave a Reply. |