These amphipods were discovered by scientists from the University of Aberdeen in waters more than 4 miles deep, north of New Zealand. Similar shrimplike crawlers may lurk at the bottom of the Challenger Deep. Oceanlab/University of Aberdeen/AP hide caption

itoggle caption Oceanlab/University of Aberdeen/AP

Sugar, coffee, fruit juice for babies, oil and salt inside a market subsidized by the government in Havana on July 11, 2013. Enrique De La Osa/Reuters/Landov hide caption

itoggle caption Enrique De La Osa/Reuters/Landov

Rob Knight, co-founder of the American Gut Project at the University of Colorado in Boulder, works in the lab where the samples are processed. The American Gut Project hide caption

itoggle caption The American Gut Project