How do you learn to draw animal heads from any angle? Practice drawing them from three. If you master the front, side and three-quarter views, you will be able to interpolate any other head position. This also help you to visualize the head as a three-dimensional object rather than outlines around a flat shape. In this demonstration I construct three generic predator heads (two dogs and third that starts out dog-like and turns into a lion). Draw along with the demonstrations. As you do, notice how the same features appear from different angles. Then choose a few mammal species and draw their heads using photo reference (online image search) in all three views.
Click on the first image to start a step-by-step side-show.