German Shepard floppy ear

Question
I just adopted a 4-5 year old german shepard/collie mix.  I noticed that he can't hold up his left ear.  It just flops around, but his right ear is perfectly erect.  I don't believe its an ear infection because he hasn't been shaking his head and when I touch the ear it doesn't appear to be sensitive.  Is this something that needs vet attention?

Answer
I doubt there is much the vet can do.  It varies how soon, but most erect ear dogs' ears eventually stand up.  A few don't.  it may be a behavioral thing.  Some time when you are in something, you might ask the vet about it.  Sometimes they can do surgery.  If you haven't had him to the vet yet, a check up and get acquainted visit might be a good idea.  Take any medical records you have.