Otter tracks in hydrothermally heated mud next to %26quot%3Bfrost flowers%26quot%3B at the edge of the Yellowstone River. %26quot%3BThe tracks are at the end of an otter slide down a snow slope that leads up to where an otter has eaten several fish leaving only shards of skin%2C the coarser bones%2C and a nearby midden of urine and scat%2C%26quot%3B Fuller says.