RENO -- A new study says more than 500 black bears have returned to parts of their historic range in the Great Basin of Nevada where the species disappeared about 80 years ago.

Scientists say new genetic testing confirms the bears are making their way east from the Sierra ranges north and south of Lake Tahoe along the California line.

In some cases, recent generations have moved hundreds of miles to sites near the Utah line.

The researchers say it's a rare example of large mammals recolonizing areas where they'd been wiped out.

The new data provides ammunition for advocates of increased protection of wildlife corridors for a number of species in the basin, a vast stretch of desert and mountain ranges that covers most of Nevada, half of Utah and parts of Idaho, Wyoming, Oregon and California.