Going the other direction (EN>CZ), "Je to váš vlk?" is also an accepted translation. They are pretty much equivalent, but one of the CZ natives on the team may add something about how they may differ, if they do.
Subtle difference indeed, you can use both in the same situations.
But for example: To je VÁŠ vlk? is better when you are surprised that it is THEIR wolf.
For a simple question both are fine.