Science

A female orca named Wikie swims with a calf in 2011 at Marineland in Antibes, France. Wikie was the central animal in a study, published Wednesday, about orcas' ability to imitate human speech. Valery Hache/AFP/Getty Images hide caption

Middle Palaeolithic artifacts recently excavated from Attirampakkam, an archaeological site in present-day southern India. The artifacts suggest the technique used to make them spread across the world long before researchers previously thought. Sharma Centre for Heritage Education, India/Nature hide caption

Ocellated turkeys stand out for their bright blue heads and iridescent feathers. They're still around the Yucatan today. Wolfgang Kaehler/LightRocket via Getty Images hide caption

Smoking is the No. 1 cause of death among people with severe mental illness. Luis Diaz Devesa/Getty Images hide caption

What scientists believe to be our oldest ancestor, the single-celled organism named LUCA, likely lived in extreme conditions where magma met water — in a setting similar to this one from Kilauea Volcano in Hawaii Volcanoes National Park. Danita Delimont/Getty Images/Gallo Images hide caption

The moon rises between two office buildings in Bangkok, Thailand. Lillian Suwanrumpha/AFP/Getty Images hide caption

Some of the "milks" on offer by Elmhurst Milked, which operated as a traditional dairy in New York for nearly 100 years. These days, Elmhurst has replaced cows with nuts, oats and rice. Courtesy of Elmhurst Milked hide caption

The IMAGE spacecraft undergoes preflight testing in March 2000. NASA hide caption