Board Thread:Speculation House/@comment-120.28.223.121-20140817041624/@comment-25405817-20150106032241

It might also be an animation limitation: The head models for all the characters may have default elements that can't be removed while designing the character in the 3D model, like eyes, nose, mouth... and ears.

So, we cannot be sure if the two pair of ears is an intentional detail or if it's just a limitation of the software... unless we ask Monty himself.