Thor earned a master's degree from the University of Vermont's Field Naturalist Program and completed his doctorate in 2006 through a joint program at the University of Idaho and the Centro Agronómico Tropical de Investigación y Enseñanza (CATIE), Costa Rica. His dissertation research described the effects of forest fragmentation on the pollen dispersal, seed dispersal and conservation genetics of rainforest trees. Thor is a member of the Human Ecosystems Study Group with current research interests in plant-animal interactions, native bees, and the ecological impacts of warfare. He works as an author and independent conservation biologist. His book FEATHERS won the 2012 AAAS/Subaru SB&F Prize for science writing, as well as a 2012 Pacific Northwest Booksellers Award. His first book, THE IMPENETRABLE FOREST, won the 2008 USA Book News Award for nature writing. Hanson lives with his wife and son on an island in Washington State, and is currently working on a new book about the evolution and natural history of seeds, due from Basic Books in 2014.