Donald Trump  as he announces his candidacy for the US presidency:  his comments about Mexicans   have made him stand out in a crowded field of Republican candidates. Photograph:  Christopher Gregory/Getty Images

It’s hard to say what’s more shocking: the outrageous remarks property magnate Donald Trump has made since he announced his presidential candidacy or (...)

Diver Susan Bird working at the bottom of Hoyo Negro, a large dome-shaped underwater cave on Mexico’s Yucatán Peninsula. She carefully brushes the human skull found at the site while her team members take detailed photographs. Photograph: Paul Nicklen/National Geographic

Cave divers have discovered one of the oldest human skeletons yet found in North America. Near perfectly preserved, the bones yielded DNA that has hel(...)

A newly hatched  loggerhead turtle on a Cyprus beach. Photograph: Reuters/Andreas Manolis

Scientists have developed a robot that mimics the movements of a newborn sea turtle as it struggles across the sand towards water. They hope th(...)