At first glance, a Coyote looks a lot like a Red Fox. Their size and coloration are about the same. The most obvious difference between these two animals lies in their tails. The tip of a Coyote’s tail is dark, while a Red Fox has a white-tipped tail. Also, a Coyote runs with its tail down, and a fox runs with its tail pointing straight out behind it. Another distinction is in their calls: both yip, but the Coyote quite often emits a series of barks and howls prior to its yipping calls.

http://enature.nationalgeographic.com/articles/detail.asp

The Coyotes of the east tend to be much larger than its western cousin. This is mainly due to the fact that Eastern Coyotes are crossed with the Gray Wolf which gives them considerable size and mass. But for the most part, Eastern and Western Coyotes have the same behavioral patterns. If anything the Eastern Coyote are more cautious/shy.

Tip of the tail is the big difference. Coyotes are black tipped. Foxes are white. Sometimes coyotes are bigger though I've seen some small scrawny ones. In the Eastern states the red coloring of foxes usually is quite bright, beyond any redness of a coyote. The fox usually has a pointier snout.

They run differently- a fox has its tail straight out behind it when it runs , a coyote runs with its tail betwen its legs. Coyotes are larger and taller than foxes. Their running gait is also different, with a coyote having more of a circular motion behind

Here is a red fox i feed chicken wings and catfood.Foxes are not related to wolves they are actually closer to cats .A gray fox which is more commonly in the south can climb trees .Their northern red cousins cannot.