I agree with Black Spot. Especially in the Wolf drawing, there's a real lack of some nice contrast. The darker shade in your drawing is the nose, which is good - that's the darkest in the photo as well. But in the photo there are other areas as dark as the nose, like around the eyes, inside the ears, the folds in the fur and the background. Don't be afraid to go dark; contrast in the right places makes a piece pop and lets you direct the viewer's attention where you want them to look. As far as pencil strokes go, though, yours are really good - they follow the direction of the fur and create a nice texture. He looks almost pet-able.
The fox is better in that aspect (although the tail is a little pale compared to the photo), but what's missing there is some a well-defined and detailed outline. The legs, for example (it's most visible there), look more like rubber boots because you flattened the small hairs that made them feel like fur.
The legs look ok, I guess...it's hard to say because from this angle they don't even look right in real life, not to mention a quick pencil sketch.
I suggest 2 things:
1. If you want to improve this kind of pencil work, get a softer pencil, like 2B or 4B (or higher, if you want. I always found the real soft ones harder to work with), and don't be afraid of contrast.
2. Try figure drawing, from life or from photos. As challenging as it may be drawing things you're not closely familiar with like wild animals, it's even more challenging to draw things you see every day, and getting them to look right.
thanks to everybody posting, that's a nice observation, none pointed me out the lack of contrast in the pictures, i used for the wolf picture a 4h pencil,a 2h and a 2b pencil, but yes, i suppose i should work with darker pencils in my next pictures
the paintover was a nice thing as well, makes me see things i didnt saw before, thanks a lot!
Good work so far. Your sense of proportion seems pretty good. Adding more of a value range (darker darks, lighter lights and plenty of middle values) is a great suggestion in the previous replies. The fox legs aren't quite as good as the fox and wolf faces right now but that's all about practice I think.
Keep drawing drawing drawing and update that sketchbook!
The toughie with drawing the furry friends from a photo, is that you don't get to see how they're put together - anatomy has to be kind of a seperate study to get down first.
Like the fox. The eyes of a canine (like most other mammals) are set into an eye socket. Keeping that in mind will help the eye from looking as though it's floating on the surface of the head. Looking at pictures of skulls will help nail the shading.
The legs have 'elbow' joints which are a bit hard to see in the ref you used. Look carefully, and find some more pictures. That'll help keep your legs looking real.