By Sid Perkins
Normal 0 false false false MicrosoftInternetExplorer4 The biomass lost via the extinctions of large mammals such as mammoths and giant ground sloths during the last 50,000 years has largely been replaced by that of one species, Homo sapiens. The unprecedented success of humans is in large part possible only because people take advantage of fossil fuels, a new study suggests.
About half of the mammalian megafauna species — loosely defined as those tipping the scales at 44 kilograms or more — have died out in the past 50,000 years, says Anthony D. Barnosky, a paleoecologist at the University of California, Berkeley. That leaves only about 180 non-human mammalian species of that size on Earth today, he reports in the Aug. 12 Proceedings of the National Academy of Sciences.