YOUNG: It’s Living on Earth. I’m Jeff Young.

CURWOOD: And I’m Steve Curwood.

Coming up: the rest of the story behind the 1909 North Pole Expedition. But first this Note on Emerging Science from Lindsay Breslau.

BRESLAU: Haunting and beautiful, a wolf's cry pierces the darkness of a Montana night. The wolf believes it's answering a call from a fellow Canis lupus, but it’s been hoodwinked. The "call of the wild" it replies to is a recording played by a small box on a nearby tree.

BRESLAU: The Howlbox runs on solar power and plays a recorded howl twice a day, at dawn and dusk. As soon as it emits a cry, the box switches into record mode to capture any responses. It then goes into "sleep" mode until the next programmed recording.

The gray wolf of the northern Rocky Mountains was removed from the endangered species list in March, and it is now up to the states to keep tabs on the wolves, as well as fund the project. The Howlbox is cheaper and less invasive than traditional tracking methods like radio collars and aerial monitoring. It's one of several new inventions by the University of Montana, the Nez Perce tribe, and other organizations, to reduce the cost of tracking.

University researchers will continue to test the Howlbox this summer on a large wolf population in Idaho. They hope the call and response device will be a howling success and make tracking easier, especially in isolated areas.

That's this week's note on emerging science. I'm Lindsay Breslau.