Fishermen drag a net in Lake Malawi in 2012. About the size of New Jersey, the lake is home to hundreds of fish species and is considered one of the most biologically diverse lakes in the world. Ding Haitao/Xinhua/Landov hide caption

itoggle caption Ding Haitao/Xinhua/Landov

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

The World Trade Organization has maintained the EU's ban on products from Canada's seal hunt. Earlier this year, activists from PETA simulated slaughtering a seal in a protest at the Canadian Consulate in Los Angeles. Joe Klamar/AFP/Getty Images hide caption

itoggle caption Joe Klamar/AFP/Getty Images

The egg definitely came before the chicken in this case — the skeleton is from a modern adult kiwi, the egg from its much bigger, long-extinct cousin, Aepyornis maximus. Kyle Davis and Paul Scofield/Canterbury Museum hide caption

itoggle caption Kyle Davis and Paul Scofield/Canterbury Museum

In this image from the June issue of National Geographic, Jose Armenta and his wife, Eliana, relax with their Boston terriers Oreo and Sassy, and Zenit, a German shepherd they adopted from the Marines. Adam Ferguson/National Geographic hide caption

itoggle caption Adam Ferguson/National Geographic

When your best friend weighs several tons, sometimes a trunk hug will have to do. Scott Raffe/Courtesy of Shotwell Media hide caption

itoggle caption Scott Raffe/Courtesy of Shotwell Media

Unlike humans, an octopus doesn't have constant awareness of each arm's location. Each appendage sort of has a "mind of its own," research shows. Joe Parks/Flickr hide caption

itoggle caption Joe Parks/Flickr