What animal is dark brown with black mane shaped like coyote?

The animal you are describing is likely the black-maned version of the domestic horse, specifically a breed such as the Mustang or an Arabian horse. However, if you're referring to a wild animal, it could resemble a coyote, but there are no direct wild animals that fit that exact description. In general, horses can have a variety of coat colors and mane styles that might evoke that image.