I actually didn't notice it was in the shape of a dog at first. Maybe try something to make the features a little more noticeable, like the eyes and ears maybe? Other than that great concept, I like it!
I agree with Mattsack. It would really help if you could make the dog features more noticable. I didn't even get the idea until I read your description. I like the idea though! It might also help if you added just a hint of color to it too!
About my design
One color print on white! But it will work on any color tee. Enjoy!