Topic: William Ripple

SAN MATEO, Calif., June 22 (UPI) -- More large predators such as cougars are needed in wild lands in the western United States to enhance overall wildlife populations, two scientists say.

CORVALLIS, Ore., May 3 (UPI) -- Scientists said the disappearance of cougars from Yosemite National Park in the 20th century disrupted the entire ecology of the valley.

CORVALLIS, Ore., July 27 (UPI) --

BOULDER, Colo., Feb. 23 (UPI) -- A series by UPI examining the relationship of humans to the environment. This week: Despite its longstanding bad reputation, wolves can work some wonders on local ecosystems.