Ashley Ahearn

The Cascades frog used to occupy alpine zones from California to the Canadian border, but its range is shrinking as global temperatures increase and snowpack declines. Scientists are hiking deep into the mountains of the Northwest to study the tiny frog, which makes a call that has been described as a "chuckling" sound.

Scientists are worried about the elusive members of the weasel family that live in parts of Olympic National Forest in Washington state. To see whether martens are endangered, volunteers are installing remote camera traps to take photos of the animals.