One of the biggest problems that all artists strive to overcome is perception vs. reality. In order to draw with "good anatomy", you will have to get over your perception of what you think an animal or object looks like in your mind, and instead draw what you are actually, physically seeing.
Because our brains can alter things and perceive them in different ways than what the actual thing is. I hope I'm explaining that okay.
Anyways, the very best way to do this is to go out and draw things from life. Looking outside and drawing the landscape around you, the bird in your yard, or your dog as it runs around outside. Drawing things from life allows you to get a better understanding of them. It helps you to see the motion, movement, and how things (like joints and muscles!) function and flow together, which will be reflected in your drawing. Once you understand how something works, you will be able to identify in a drawing, "Oh, the dog in that drawing, its legs wouldn't work very well, they would act like jello/wouldn't give him balance." If you can't draw something from real life because you don't have the animal in front of you, then you should still at least watch videos of the animals online before you resort to just drawing based off of a still image. Don't give up and go straight to the still images. Drawing something based off of a moving picture challenges your brain to actually comprehend the animal, its structure, and how it functions. You can really tell the difference when something is drawn based off of a still screen vs. from real life/movement. And //never// practice anatomy based off of another artist's drawing. Every artist still has their individual perception that is reflected in their drawing(it's called "style"), and so you shouldn't assume their anatomy is perfect, its not.
I recommend drawing a rough skeleton and/or joint points during your sketching phase, as this helps you form the actual body. Another good way to practice anatomy is taking pictures of dogs/wolves/what have you off of google and trying to draw the skeleton of the animal on top of the picture.
