By Subodh Varma
NEW DELHI: Despite going through two ice ages, a volcanic super-eruption and the arrival of humans, most of the big mammals of India like bears, leopards and wolves have continuously lived in the region for 200,000 years, a new study of fossils has revealed.
This is in sharp contrast to northern Eurasia, Australia, Madagascar and the Americas, where nearly two-thirds of mammals died 10,000 years ago.
The researchers from universities in UK, USA, Australia and Karnataka searched for animal fossils in caves in southern India to find out since when these animals have been roaming the Indian countryside. The fossils were buried deep in ancient sediments in the caves. Some of the caves' chambers contain ten-metre-thick sediments, made up of layers of mud slowly deposited over thousands of years. The fossils were dated to build a timeline of the animals, just as it has been done for animals in the Americas, Europe and Australasia, but not, until now, for the Indian subcontinent.
Professor Michael Petraglia of the University of Oxford, who led the study and his colleagues found that 20 of 21 mammal groups from at least 100,000 years ago are still living in India today.
'We managed to successfully date this long sequence going back 200,000 years. We saw a broad-scale continuity of fauna and in the wider perspective, our findings conflicted with other major extinction events,' said Petraglia, according to a report in Planet Earth Online.
'The relative stability of rainfall and topography across the Indian subcontinent as a whole meant that habitat survival in patches facilitated faunal recombination, migration, and general long-term persistence,' write the authors. The study has been published in the scientific journal Proceedings of the National Academy of Sciences (PNAS).
The research indicates that many of India's well-known animals may have been more able to adapt to ecological pressures than mammals elsewhere. The study also highlights the importance of connected habitats and could help protect some of today's most endangered Indian creatures.
Researchers think India's mammals survived crises by moving between connected safe havens, known as refugia. More stable weather in the area over the last 200,000 years compared to other parts of the world could also have played a part in the mammals' persistence.
This study contradicts the prevailing view that widespread extinctions affecting far-apart places like North America, Europe and Australia must have been worldwide phenomenon, caused by single problems like climate change or overhunting. Such extinctions occurred in the Late Pleistocene age which lasted from about 2.58 million years ago till about 11,700 years ago.
'Most of the research on mega-faunal extinctions over the last 30 or 40 years has focused on North America, Australia and Madagascar, so that has shaped our thinking on the topic. These places saw much more extremes of climate change than the Indian subcontinent did. These and human factors may have led to big changes in faunal populations,' said Petraglia according to Planet Earth Online.
'But it now seems that major extinctions during the Late Pleistocene weren't a worldwide phenomenon after all, which was surprising,' he adds.