Keystone species anchor our ecosystems — from the ancient, towering sequoias to the sweeping migrations of caribou. Since our founding, #NatGeoExplorers have worked to document and protect the United States’ wildlife and landscapes. As we celebrate America’s 250th anniversary, we embark on the next chapter of that work to preserve the country’s iconic species. If you could live a day in the life of any wild American icon, which would you choose? Photos by Explorers JoelSartore (1), CarltonWard (2), AmyToensing (3) and Ronan_Donovan (4)