I heard that it doesn't hurt their ears, but is rather a throw back to the howling that wolves do. My husband can start howling, and soon enough Hudler joins, then Maddy, then Grace. I don't know if the "wolf pack theory" is really true, but it's true in our house.
hmm, that's interesting. I used to own a lab who did that too. (he's at the rainbow bridge now.) :'(
Although i'm not an expert, I believe it has something to do with the siren's pitch and frequency, that triggers that. I currently own a mixed-breed (Smooth-coat St. Bernard/lab) that howls whenever one of those large millitary jets go over-head. Weird, i know.
Thanks, all, I was just curious... when they were a few months old, it was so cute; they both looked like Snoopy with their noses up in the air. We have moved since then, and our neighbor's house is quite close. They have no pets or children, so I am most sensitive to their privacy. Lil and Legend spend time during the day outside when everyone is at work and for a little while on the weekend mornings. Needless to say, a siren sound will get them going at 7:30 on Sunday morning. Ha ha... a quick run downstairs and in they come.