Wolf Traits ID--Part One
I use sort of a checkpoint system for "wolf traits"; I look for the things mentioned below...nothing is completely exclusive to wolves--anything found in wolves can be found in dogs as well--, but an animal with *many* of the traits listed below may be part wolf...especially if it was sold as a wolfdog. (I rarely expect a stray animal--that came to humans to be caught, no less--to be a "true" wd...it does happen, but in my experience, most shelter strays labelled "wolves" are just mixed breed domestics that someone thought "looked sort of wolfy" ;)
Note that these are "
WOLF traits", not "wolfdog traits". Wolfdogs are a mix of wolf and dog, and can take after either animal on any given feature.(!) A "high content" wolfdog will have almost all of these physical traits. A low content wolfdog may not have any more of the traits than a northern mixed breed dog!  Behavioural traits are more subjective, of course...as behaviour is determined in part by how the animal was raised.
Coming at it from many angles, taking ALL aspects of the animal into consideration, you usually get a decent idea of what you're dealing with.  You still can't always tell though...especially if all you have to go off is a photo or two. And BEWARE--there are a few dog breeds that do have many wolf attributes! There is a LOT of overlap between wolves and dogs. That said, here are some pointers:


Ears: small, rounded, shoeleather-thick, heavily furred inside (not big & pointy like GSD ears). Erect at just a few weeks of age; wolf pups do not have flop-over ears. (Malamute ears are set further out on the head than wolf ears. Husky ears are pointier at the tips, and set high on the head. GSD ears, of course, are much larger and thinner!)

Eyes: light/pale (but NOT blue!), almond-shaped, slanted/"Chinese-looking"/obliquely set in the head...usually are
yellow, green, orange, or amber...occasionally light brown. Very intense look about them. Presence of a tapetum--i.e., the eyes reflect back brightly when a light hits them dead-on from a distance. "Red-eye" (caused by lack of a reflective layer in the eye) is a dog trait. See
http://www.wolfdogproject.com/eyes for more detail.

Nose, Lips, Eyeliner, Gums: always black, not pink or spotted. Very important for communication purposes, and are supposed to be highly visible from a distance.

long, curved...large in proportion to dog teeth.

Head: large in proportion to the body. Snout is long and tapered, as opposed to the malamute "snub nose". Forehead is very flat, the stop is not at all pronounced. (i.e. if you run your finger up along the top of the muzzle, on a *dog* you hit a "wall" at their forehead. On a wolf, you glide right up to the top of their head without any speedbumps.)

Back: straight, no downward slope like a GSD.

Body: very elongated, tall, and narrow (not barrel-chested like a sibe).

Legs: very long for the dog's overall size. Front legs close together at chest, shoulder blades--as viewed from the back--should be close together, causing knees to be held more in towards the chest. Toes pointing slightly out(rather than pointing forward like a dog). Back legs are 'cow hocked'. Unusually long pasterns.

disproportionately large. Not "large" like GSD paws, but more like "enormous" (esp. in arctics!) Toes are very long, and the overall footprint is more elongated than most dogs. (By comparison, sibes have a very round--almost catlike--pawprint.) Fur between toes. Toenails and pads of paws are black. No rear dew claw.

straight and bushy. Looks like a bottle brush. No curl (most dog breeds have some curl), and no "flag tail" as seen in GSDs. Wolves' tail ends above the hock, unlike GSD whose tail extends below the hock.

Fur: double-coated. Stiff, long, black-tipped outer guard hairs; has a mane/ruff around the neck area, and longer "cape" hairs on the back (near the neck). Thin & wiry coat in summmer, but grows a thick coat for winter. Not normally super-soft or extra-fluffy like some domestics...though there is some evidence that diet/illness can affect this.

Colours of fur: each hair is banded with several colors along its length, as opposed to being one colour all the way through. That's what gives the well-blended sable appearance. Sharp markings, such as those seen on siberians, are a dog trait. Even on a white or black animal, the wolf saddle or "cowl" (further forward than a GSD saddle) should be slightly visible.
Wolves are never one solid coulour (i.e. pure white), and they get a grizzled appearance as they age. Precaudal mark on tail is plainly visible (even in black or white animals), and made up of stiffer hairs than the rest of the tail. The gland--not just the mark--is also present. Markings are symmetrical: never a black spot over one eye, nor one tan ear and one white one. "Eyebrows" are visible, but are well blended as with the rest of the coat. Mask comes down the bridge of the nose, and around the eyes, i.e.
"closed faced". "Open faced" or other odd markings signify mal or husky. No intentionally bald areas, such as the bald tummy on some dog breeds.

Cottonwoods has an excellent "Buyer Beware" page w.r.t. wolfdog content.

Pictures are worth a zillion words!  :) The best way to learn to phenotype wolf content is to look at MANY wolves, wolfdogs (of varying, known, verified content) and fully domestic dogs...both in person, *and* in photos. I suggest checking out these two sites:
http://www.interl.net/~iowolfer/page4.htm     for reference.
And for comparison, look at some northern breeds...you can start here:
More wolfish looking breeds HERE.
You can search for "Alaskan malamute", "Husky", and "Samoyed" on
Google's Image Search.  Malamutes in particular range from very wolfish, to more plush and bear-like.  ;)
German Shepherds also look quite wolfy! Shepherds, being popular, tend to vary substantially from their breed standard, and also by their line, and/or country of origin.
New: Come over HERE to see some of the range available in shepherds, malamutes, and huskies! :)
Most especially, study
wolves!  In person is best, but here are some links to wolves/extremely high content wolfdogs. 1 2 3 4 5

Misc. wolf tips: Pures are only fertile part of the year; pups ONLY born in the spring. On a male, testicles are smaller in summer when they are not fertile. Pups are always born greyish-brown or black, even those animals that will be white when grown.