Near the beginning of Teen Wolf, Scott Howard is noticing bizarre changes happening to him.
Scott is speaking to his father in his father's hardware store and starts covering his ears in agony because of an annoying high pitched sound. Mr. Howard seems oblivious as to what was wrong with Scott.
Scott: What is that noise?
Mr. Howard: What noise?
Scott then finds that the source of the noise was a child blowing on a dog whistle thinking that it was broken.
It is later revealed that Scott is in fact a werewolf. Scott's father, Mr. Howard reveals to Scott that he is also a werewolf.
If Mr. Howard is also a werewolf, why didn't he hear the dog whistle that was bothering Scott so much?