I don’t know how long it had been observing me, but now it peered at me with some alarm. Then the little animal–only slightly larger than a house cat–threw back its head, gave a single, shrill bark, and disappeared in a trot over a ridge. I chased after it over the hummocky tundra, but when I got to the top of the ridge, the fox was nowhere to be seen. The polar desert stretched out for miles in front of me–no trees, no shrubs, no deep valleys, just the gently rolling land, tufts of arctic grasses, and scattered wildflowers. Yet the fox was gone.