Who are you trying to scare here....
Well, Rotties are like labs with the floppy ears....but they will raise their ears when something gets their attention.
You know for show...this is equally important.
So He really likes cats...wants to play & lick them....so when I say "kitty?" or "where's the kitty?" .....he automatically perks up.
When I take him on walks.....I talk to him.....tell him "what's that? or listen"....he automatically just stops everything (even panting) & goes into observe mode. Otherwise....he will just plod around with no worries like he normally does.