Big brown bats like this one are relatively common in urban areas, sometimes roosting in buildings. Contrary to popular belief, bats rarely carry rabies and are not rodents. They belong to the order Chiroptera, which means "hand-wing." Courtesy of Robert Marquis hide caption

itoggle caption Courtesy of Robert Marquis

Researchers raised two groups of walking, air-breathing Polypterus senegalus — one on land and one on the water. They discovered that each group was able to adapt to be best suited to its environment. A. Morin, E.M. Standen, T.Y. Du, H. Larsson/McGill University hide caption

itoggle caption A. Morin, E.M. Standen, T.Y. Du, H. Larsson/McGill University

A technician tests fluid samples from Ebola-infected patients at a field lab, run by Doctors Without Borders, in Kailahun, Sierra Leone. Tommy Trenchard for NPR hide caption

itoggle caption Tommy Trenchard for NPR

The granulated surface of the lake bed known as the Racetrack is a favorite destination for tourists — and for scientists who want to investigate trails left by the meandering stones. Momatiuk - Eastcott/Corbis hide caption

itoggle caption Momatiuk - Eastcott/Corbis

A scientist tests a patient's blood for Ebola at the European Mobile Laboratory in Gueckedou, Guinea. The first cases reported in the outbreak occurred in a small village about eight miles outside Gueckedou. Misha Hussain /Reuters /Landov hide caption

itoggle caption Misha Hussain /Reuters /Landov