This week's dirt: New species for 2012 includes sneezing monkey, zebrafish "smell fear", harvestman spider managed to cross the Pacific Ocean 82 million years ago, tomatoes contain more genes than humans, and more.

The couple answer your questions about their time in the Frank Church-River of No Return Wilderness, wolf sightings, and the making of the PBS Nature film.

In this video, a family of bison ward off a pack of wolves as they begin to feed on a fallen calf. Watch a scene from the PBS Nature film, Radioactive Wolves.

The ghost city of Pripyat was once a thriving metropolis. Today, it's a city that is green, in an unnerving and unintentional way.

Scientists study wolf pups living outside Chernobyl's Exclusion Zone in an effort to assess the health of those populations born inside the radioactive area of Chernobyl. Watch a scene from Radioactive Wolves.

A romantic adventure becomes something much greater in the Frank Church-River of No Return Wilderness. Watch the full episode of the PBS Nature film, River of No Return.

Packs, howls, and bows. Facts and stats about the gray wolf: the largest member of the canine family and ancestor of the domestic dog.

After reaching Chamberlain Basin, Isaac and Bjornen come across white-tailed deer and their first glimpse of wolves in almost two months. The wolves and deer pay no attention. They're already intent on an ancient game. Watch the video.

Isaac and Bjornen come across a group of wolf pups exploring their home, right off a trail in Idaho's Frank Church-River of No Return Wilderness. Watch video.

Isaac and Bjornen play harmonica deep in Idaho's Frank Church-River of No Return Wilderness, while the area's wildlife listens, surrounded by the brilliant natural landscape. Watch video.