It is always, without question, better to draw from a photograph than from another drawing. I would even say it's better to draw from a photograph than to simply follow a tutorial. If you want to know and study what a wolf really looks like, you're going to need actual, real pictures.
I looked around a bit for a picture you could work from best, and here's what I found. It's suprisingly close to your picture in angle and perspective.
Here are some redlines to guide you with your editing, so you'll know where to look and what to work on.
A few pointers:
- The length of the muzzle
- The size of the nose
- The placement and size of the eyes
- The placement and length of the fur
- The placement and shape of the ears
Study wolves carefully if you look to draw them right. Actual wolves, not drawn ones. You don't want to copy other people's mistakes ;).