Coyotes: While coyotes are generally a grayish-brown color, they can have a reddish hue, particularly in areas with sandy soil. However, they aren't typically described as "very thin" in appearance.
Other potential candidates:
* Feral dogs: These are domestic dogs that have gone wild. While they can be thin and exhibit various colors, they are not native to Arizona and are less common than coyotes.
* Red wolves: These are endangered wolves found in the southeastern United States. They are not present in Arizona.
Important note: If you see an animal that you think is a wild dog, it's best to observe it from a safe distance and avoid approaching it.
If you have concerns about a particular animal, it's always best to contact your local wildlife agency or animal control.