On a wooded hillside along the banks of the Allegheny River, Gabrielle Marsden brushed up against an oblong leaf: Asimina triloba—the American pawpaw. The deciduous tree bears North America's largest ...

A 9-year-old zebra was found dead in her stall Tuesday morning at the San Francisco Zoo after apparently falling ill Sunday, leaving the zoo with only one zebra, according to zoo officials. Also ...

Answering questions about zebra mussels and tree claims. Answering viewer-submitted questions about zebra mussels and tree claims. Is there a natural predator for zebra mussels? Tree claims hold wild ...

A wild scene unfolded on Staten Island Wednesday when a zebra and a pony were spotted running along a busy roadway after they apparently escaped from a Christmas tree seller. Part of their journey was ...

Pittsburghers Preserving Pawpaw Trees, Some Hope It Will Lead to More Zebra Swallowtail Butterflies On a wooded hillside along the banks of the Allegheny River, Gabrielle Marsden brushed up against an ...

A wild scene unfolded on New York's Staten Island Wednesday when a zebra and a pony were spotted running along a busy roadway after they apparently escaped from a Christmas tree seller. Part of their ...