It makes for a dramatic narrative: Roughly 252 million years ago, a mass extinction event killed up to 96 percent of marine life, earning an infamous name in the geologic record, "the Great Dying." However, a new study suggests that this cataclysmic event has been overestimated. In the February issue of EARTH Magazine, read how a University of Hawaii paleontologist is improving our understanding of mass extinction events by exploring the effects of natural variability on background extinction levels, revealing a clearer signal in the noise.

EARTH Magazine explores new research on the "P-T" mass extinction to look at what caused it, and how it can inform our understanding of today's ongoing extinction event.

As we celebrate National Fossil Day, EARTH Magazine brings you a story set in Pleistocene South America, and was home to large megafauna species like giant sloths and saber-toothed cats. At some point as the climate warmed and human settlers began hunting, the megafauna living in Patagonia and Tierra del Fuego went extinct.

Alexandria, VA - Saber-tooth tigers, dire wolves and woolly mammoths conjure up images of a past when large beasts struggled against the elements, each other, and even against humans for survival. Thousands of these creatures met their demise in the muck of the La Brea tar pits in Los Angeles, where they slowly sank into the tar and were fossilized. Now, scientists are using traces from hungry, bone-eating insects on these fossils to investigate how long it took for the giant beasts to be swallowed up by the sticky, oozy substance.

In the Late Quaternary, Australia was home to an array of megafauna. The half-ton Palorchestes azael, the rhinoceros-sized Diprotodon, and even the giant koala, Phascolarctos stirtoni, roamed Australia's interior. However, between 50,000 and 45,000 years ago, they all vanished. Although recent studies indicate human colonization as a potential cause of their extinction, the exact mechanism has never been resolved. Now, geologist Gifford Miller from the University of Colorado at Boulder and his colleagues believe they have uncovered the answer.