While we were visiting the Chincoteague National Wildlife Refuge last month, we spent most of our time beach combing. On our last day, we got to the beach in the morning when the tide was out and the tracks left behind by the night time visitors to the mud flats were still undisturbed.
What are these tracks of? Pets are not allowed in the refuge, which rules out dogs. According to a little brochure I picked up at the Visitor's Center, red foxes (Vulpes vulpes) are common in the refuge, coyotes (Canis latrans) are rare and there are no wildcats.
The drawing* below compares fox and coyote tracks. According to Stokes & Stokes, the crucial difference is the straddle length (the sideways displacement between two steps; the distance between the horizontal lines in the drawing), which is shorter in the fox.
In the track photographed on the beach the foot prints have a very short straddle; they are almost on one line. Therefore, I believe they belonged to a red fox. Similar tracks were all over the mud flats that morning. Either one or several foxes had been active the previous night. Here is a closer view of a pair of prints (the ruler is 15 cm long).
*Stokes & Stokes. 1986. A Guide to Animal Tracking and Behavior. Little, Brown & Co.