A pair of gray foxes (Urocyon cinereoargenteus) is at home in a tall ironwood tree, high above the Sonoran Desert floor. The species first evolved more than 7 million years ago in the lush tropical forests that once covered what is today’s American Southwest. Since that time, this anatomically distinct fox has accumulated an impressive array of un-fox-like adaptations for life in the canopy, including primate-like flexible wrists and cat-like paws with long, curved claws that allow it to grip tree branches. This arsenal allows this uniquely arboreal fox species to sneak up on birds roosting near the tips of branches and to drag heavy objects—here, the skeleton of a fawn—into the canopy. Fox pairs use the skeletons as pungent scent posts to mark their territories. Particularly after rain, the smell of these “skeleton trees” can be quite powerful and can carry great distances.

Tucson, Arizona

Alexander V. Badyaev

A professor of evolutionary biology at the University of Arizona, Badyaev is also a regular contributor to several international natural history magazines. His scientific work, nature photography, and popular science writing have been recognized by major international awards and fellowships. Most recently he was a Kavli Fellow of U.S. National Academy of Sciences, a Fellow of American Association for the Advancement of Science, and a winner of the BBC Wildlife Photographer of the Year Awards.

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