The toes on a domestic dog will often splay out more in deeper mud like that. That's what leads me to think either a large coyote or a small wolf.
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“Trouble rather the tiger in his lair than the sage among his books. For to you kingdoms and their armies are things mighty and enduring, but to him they are but toys of the moment, to be overturned with the flick of a finger.”
― Gordon R. Dickson, Tactics of Mistake
― Gordon R. Dickson, Tactics of Mistake