He is most famous for his photography of wildlife in the Greater Yellowstone Ecosystem, as he has lived inside the zone in Jackson, Wyoming, for over 40 years.
After moving to Nederland, Colorado, in 1970, he spent a couple of years there living in an abandoned mining shack with no facilities, with two dogs and a raccoon.
He honed his photography skills and studied at the University of Colorado Boulder Mountain Research Station.
The university is near Nederland, which made it easy for him to study arctic alpine ecology while living in the shack.
Mangelsen desired to create a documentary featuring the Platte River, so he returned annually in the spring to film the sandhill crane migration.
Not long after, the International Institute of Photographic Arts retained a permanent collection of 21 prints of his work.
[6] An exhibition of his work was on display in September 2018 in the Durham Museum "Thomas D. Mangelsen: A Life in the Wild", and it premiered in Omaha, Nebraska.
It was a traveling exhibition that highlighted 40 "Legacy Reserve" photographs taken from the approximately four million shots of his career.
One example is his book The Natural World: Portraits of Earth's Great Ecosystems, featuring a foreword by primatologist Jane Goodall.
The book was awarded the Benjamin Franklin top honor in the Coffee Table/Large Format category by the Independent Publishers Association in 2007.
[4][3] Mangelsen's life work is best summed up in his own words: May these images inspire you to experience and preserve the wonders of our natural world.
[3]On May 6, 2018, Mangelsen, who lives in Jackson Hole, Wyoming, appeared on an episode of CBS 60 Minutes with reporter Anderson Cooper.
The previous September, for example, he waited a long time for a subject to arrive at a spot in Grand Teton National Park in Wyoming.
"He especially likes the dangerous kind", whether it be getting too close to male polar bears who were play fighting or photographing a Bengal tiger from atop an elephant.
In 2015, Mangelsen collaborated with Bozeman, Montana, author Todd Wilkinson to create the book Grizzlies of Pilgrim Creek, An Intimate Portrait of 399, The Most Famous Bear of Greater Yellowstone.
[6] In 2017, United States Fish and Wildlife Service officials removed grizzly bears outside the Yellowstone Park and the Grand Teton National Park in Wyoming, Montana, and Idaho from the endangered species list, also known as the Greater Yellowstone Ecosystem.
[11] In July 2018, Mangelsen helped fuel a movement that five women quickly organized called "Shoot'em With A Camera—Not A Gun."
Mangelsen has lived in Wyoming for over 40 years and has been actively involved in bear conservation in the state during that time.
[12] Then, in September just weeks before hunting season was to begin, a federal judge in Montana restored protection to all of the bears in the Greater Yellowstone Ecosystem.
The judge ruled that the United States Fish and Wildlife Service officials were "arbitrary and capricious" when they removed protection from the bears under the Endangered Species Act.
[13] In 1994 and 2000 Mangelsen won the British Broadcasting Corporation’s Wildlife Photographer of the Year Award.
[22] The award recognizes an individual or organization that has effectively communicated the values of the National Park System to the American public.
[25] His book Grizzlies of Pilgrim Creek, An Intimate Portrait of 399, The Most Famous Bear of Greater Yellowstone won several awards.
In 2015, the Los Angeles Times recognized it as a "Mesmerizing Coffee Table Title"; in 2016 it received the Foreword Indies Book Award, the High Plains Book Award, and the Outdoor Writers Association of America, Excellence in Craft Contest.