Howling at Nothing
Howling at thin air can be a sign of something wrong (such as sickness or pain), but often it simply means that your puny human ears are missing out. Dogs can hear much better than humans, so anything from a train whistle or the hum of a piece of electronics can cause them to respond with a howl. If your dog is howling at nothing, but doesn’t seem distressed, they might have a good reason that you just can’t hear.