Clint Muhlfeld, an aquatic ecologist with the USGS, holds a native Westslope cutthroat trout in Glacier National Park. Noah Clayton/USGS hide caption

itoggle caption Noah Clayton/USGS

Kalron and his team have set up video cameras that transmit real-time images of the bai via satellite. Courtesy of Maisha Consulting hide caption

itoggle caption Courtesy of Maisha Consulting

A female forest elephant charges, in Dzanga-Sangha Special Reserve in the Central African Republic. Michael K. Nichols/National Geographic/Getty Images hide caption

itoggle caption Michael K. Nichols/National Geographic/Getty Images

Pat Leiggi (right) of the Museum of the Rockies prepares to move a leg bone of the T. rex at the Smithsonian's Natural History Museum in Washington, D.C., on Tuesday. Maggie Starbard/NPR hide caption

itoggle caption Maggie Starbard/NPR

Magellanic penguins strut their stuff on the rocky shoreline of Argentina's Punta Tombo, home to the largest colony of the birds in the world. Craig Lovell/Corbis hide caption

itoggle caption Craig Lovell/Corbis

A close-up schematic of leaks near the U.S. Capitol shows high leak densities east of the building, but few leaks over the National Mall, where very few natural gas pipelines exist. Robert B. Jackson/Environmental Science and Technology hide caption

itoggle caption Robert B. Jackson/Environmental Science and Technology

Ask not for whom the wolf stalks ... Holly Kuchera/iStockphoto hide caption

itoggle caption Holly Kuchera/iStockphoto

Say aaaaaah! Dental caries and other signs of oral disease are plain to see in the upper teeth of this hunter-gatherer, between 14,000 and 15,000 years old. The findings challenge the idea that the original paleo diet was inherently healthy, says paleo-anthropologist Louise Humphrey. It all depended, she says, on what wild foods were available. Courtesy of Isabelle De Groote hide caption

itoggle caption Courtesy of Isabelle De Groote

Even when a flood obliterates homes, as Superstorm Sandy did in 2012 in the Rockaway neighborhood of Queens, N.Y., the urge to rebuild can be strong. Spencer Platt/Getty Images hide caption

itoggle caption Spencer Platt/Getty Images

In Jiaonan county, the Qi wall incorporates outcrops of bedrock. Linda Nicholas/The Field Museum hide caption

itoggle caption Linda Nicholas/The Field Museum