The remains of a new 10-meter-long predatory dinosaur discovered along the banks of Argentina's Rio Colorado is helping to unravel how birds evolved their unusual breathing system. Paleontologists led ...

Recent evidence suggests that oxygen levels were suppressed worldwide 175 million to 275 million years ago and fell to precipitously low levels compared with today’s atmosphere, low enough to make ...

Scientists have unearthed the remains of a large meat-eating dinosaur with a breathing apparatus much like a modern bird, fortifying the link between birds and dinosaurs and helping to explain the ...