Not all heroes walk on two legs.

Three years ago, photographer Charlotte Dumas took a look at the search and rescue dogs of 9/11, a decade after the animals worked to find survivors in the rubble of the twin towers and the Pentagon. The result is her “Retrieved” photo series.

“These animals were all at the same place at the same time, one decade ago, for the same reason: to work,” Dumas wrote on her website. “That experience unites them, and was the incentive for me to pursue this subject and to photograph the dogs.”

Dumas says that the images on the news of these dogs relentlessly searching the rubble day and night stuck with her. Many years after their service, these dogs live all over the U.S., and, with the help of FEMA, Dumas tracked down 15 of them to create these striking portraits of retired canine heroes.

“I can still recall these images clearly,” she wrote on her website. “The dogs searched and comforted, they gave consolation to anyone involved. Seeing these pictures, I was also comforted. They somehow emanated a spark of hope amidst this scene of destruction.”