Since I can remember there have been cases of dogs and coyotes cross breeding out here in the southwest. Usually a male coyote with a female dog. We had one that was a Shepard mix. The appearance was Shepard but it was smaller and lighter of frame with a bushier tail and behaved like a Coyote. Extremely intelligent animal, one of the smartest dogs we ever owned but a bit unpredictable and would switch to wild in an instant when in certain situations.
I was about to mention the Coydogs that are not uncommon in the Southwestern states...