Their canvas is a stretch of dingy concrete wall along Manila's main highway, where millions of vehicles stream past every day, belching exhaust that helps to create a noxious, unhealthy smog.

Rhinos have roamed the Earth for millions of years, but at the turn of the century there were only about 50 white rhinos left in the world. All were in South Africa. Over the course of several decades, South Africans brought the white rhino back from the brink of extinction.  Through incredible conservation work, there are almost 20,000 white rhinos today.

Rhinos have roamed the Earth for millions of years, but at the turn of the century there were only about 50 white rhinos left in the world. All were in South Africa. Over the course of several decades, South Africans brought the white rhino back from the brink of extinction.  Through incredible conservation work, there are almost 20,000 white rhinos today.

Decades after President Theodore Roosevelt triggered a Teddy bear craze, the black bear nearly went extinct.

U.S. Forest Service researchers have confirmed what has long been suspected about a valuable tree in Alaska's Panhandle: climate warming is killing off yellow cedar.

Scientists say preliminary tests indicate radiation didn't cause lesions and other symptoms associated with sickened or dead ringed seals found along Alaska's northern coast last year. Radiation was considered because of the timing and size of the nuclear power plant accident in Fukushima, Japan, that followed a tsunami last March.

News research shows that when it comes to a potent class of cancer-causing toxic chemicals, many American parking lots are a lot worse than some industrial centers.

Science editor Alan Boyle's blog: Experts report that the problems caused by hydraulic fracturing for natural-gas production, known as fracking, are not unique to the controversial process.

Internal documents have been leaked from the Heartland Institute, a Chicago nonprofit think tank, showing its funding of leading scientific critics of global warming and a plan to teach climate change skepticism in schools.