Sloths may seem like quirky tree-dwellers today, but their past reveals a dynasty of giants that once roamed the Americas.

Visits to the world’s tallest tree in Redwood National Park in California are now off-limits after hikers damaged the forest and left a mess, rangers reported. There’s no trail to Hyperion, dubbed the ...

A new study shows how African elephant poop helps make American-made guitars -- and how poaching of elephants is contributing to a decrease in ebony trees.