Originally Answered: What's the difference between Wolves and Coyotes?
Wolves and coyotes are different species. There are three species of wolf - the grey wolf (Canis lupus), which is the species most people think of when they hear the word 'wolf', the red wolf (Canis rufus) and the Ethiopian wolf (Canis simensis). There is only one species of coyote (Canis latrans). The maned wolf (Chrysocyon brachyurus) of South America is inappropriately named - it is not a wolf, and is only distantly related to other canids, hence its being placed in its own genus.
The grey wolf is found throughout North America and Eurasia in a wide range of habitats, and has numerous subspecies including the European wolf (C. l. lupus), Canadian wolf (C. l. occidentalis), Alaskan wolf (C. l. pambasileus), Arctic wolf (C. l. arctos), Mexican wolf (C. l. baileyi), Iberian wolf (C. l. signatus) and Arabian wolf (C. l. arabs). It is the largest member of the family Canidae at up to 175lb. They are highly variable in colour and can be grey, black, white, brown or any combination of these. All individuals of the Arctic subspecies are white. They live in packs, which are family groups, led by a dominant pair called the alpha male and female. These two are the pack's only breeding pair. The rest of the pack is made up of their siblings and/or offspring. Most packs have less than 10 members, though up to 30 has been known. They are able to take large prey such as moose or bison by working together.
The red wolf is found only in the south-eastern US, and weighs a maximum of 90lb - it is intermediate in size between a grey wolf and a coyote. It is generally more reddish in colour than either the grey wolf or the coyote, though this is variable. It has a similar social system to the grey wolf, but does not rely on group hunting to such an extent - red wolves often hunt singly or in pairs for small prey, though they will work as a team to bring down larger game such as white-tailed deer.
The Ethiopian wolf, as the name suggests, is found only in Ethiopia. It weighs only about 40lb, and though it lives in a pack, each individual hunts small prey such as rodents for itself. It is a sandy-yellow colour, and looks less 'wolf-like' than either the grey wolf or red wolf, with a narrow, pointed muzzle and larger ears. It was once thought to be a species of jackal, and was called the Simien jackal, but genetic analysis shows it to be more closely related to the wolves than the jackals.
The coyote is found only in North America. It is a smaller animal than a wolf, weighing up to 35lb. It is greyish-brown in colour, with larger, more pointed ears and a narrower, more pointed muzzle than either the grey or red wolf. It often lives in pairs, and may occasionally form small packs. It mostly hunts small prey, but packs can take down larger animals. It is highly adaptable and is often found in urban areas, making a good living off the waste food humans throw away - if you see a dog-like animal in a city, it's highly unlikely to be a wolf (wolves are extremely shy and wary of humans), but it could well be a coyote or a fox (or a stray dog, of course).
All members of the genus Canis - wolves, dogs, coyotes, jackals and dingoes - can interbreed and produce fertile young, showing that they are very closely related. Indeed, the red wolf was once believed to be a grey wolf-coyote hybrid, rather than a species in its own right. However, wolves, particularly grey wolves, usually see coyotes as competitors, and kill them.
Here are some images: