Smithsonian curator of fossil marine mammals Nick Pyenson and a team of collaborators are heading into Chile's Atacama Desert, shown here. They'll study a rich bonebed of fossil marine vertebrates that lived off the Chilean coast around 8 million years ago. The bonebed was once a seafloor that preserved the skeletons of many familiar marine animals that live offshore Chile today, as well as completely extinct animals, such as toothed seabirds, aquatic sloths, and walrus-like dolphins. The team, which includes key Chilean collaborators, is trying to understand how marine communities in the geologic past were structured differently from those of today's ocean. To do this, they'll study the bones and rocks from the bonebed pictured here. Follow the team's latest updates on the Pyenson Lab blog.