River Otters in Olympic National Park, Wash.

River otters in Olympic National Park trigger a movement-activated camera without activating the wire mesh box trap (left) used by scientists to capture the animals to attach radio transmitters and monitor their movements. The Lower Elwha Klallam Tribe is leading a project to study how the otters are responding to the restoration of the Elwha River, where two dams were removed in 2011.