I think this would be a cool thread to see what other pets hate hearing.
Because my pets hate the weirdest noises, haha.
My friendly, adventurous cat Lily hates the sound of people walking on dead leaves. I have to be careful on walks, because she will start walking super fast if she hears enough crunches.
My shy cat Tux is terrified of plastic bag noises. He will quickly run under the bed when we put groceries away or anything like that. I wonder if he had a bad experience or something before we got him. O_o
My rabbit David Bunny is usually pretty chill with music. However, when I played this song at a medium sound level, he stomped for like five minutes. http://www.youtube.com/watch?v=Ylww2dOW7fg
I'm just going to guess it's because it's T Rex and the lead singer was a rival to David Bowie during the glam rock period (haha). Or cause the guitar noises can be scary to a rabbit. XD
He also hates the blender with a passion, and I can easily see why. D:
So I have to use my blender in another room (the kitchen and living room aren't separated by a door or anything).
My dog hates the typical vacuum and thunder.
He also really hates the sound of large trucks like semis and garbage trucks.
We think we may have instilled the fear on accident by bringing him to a fireworks show when he was a puppy. >.> We always saw dogs there, so we didn't think it would be a problem, but he freaked out. We left as soon as he did, though.
Ika will climb as high as she can or hide in the darkest corner she can find when I start using the vacuum.
Gerbils I haven't found a specific sound that send them on high alert.
I scared Butterscotch last night while playing WoW, once in a while Just rolling over in my bed will send DiNozzo and McGee thumping away.... for them I think it is just when they don't expect a sound, I can play bird calls all day and they wont bat an eye at it.
Rolo + the cats all hate the vacuum cleaner. That's saying something about Rolo, because he will run towards cars outside that rev their engines. (He's on a harness so he doesn't kill himself) But yeah, he hates the vacuum cleaner.
The cats all hate loud sudden noises. Junebug and Jellybean will come running when they hear the hairdryer though. They still hate the noise, but they will run at stare at it, and Junebug will often just start slapping things its too funny.
The only noise my dogs hate is people arguing. They run away if people in the room are shouting, yelling, etc. Other than that, they're just mainly afraid of large moving objects, for example, moving furniture around.
Azrayel (my cat) is really good with noises. He doesn't mind dogs barking, fireworks, metal albums being played, drum kits, and he will sit right next to the vacuum cleaner while it's on, but he will give it the evils.
But there was one noise that he really, really didn't like. My friend was showing off his new smart phone and starting playing noises for some reason. There was one of a cat yowling, and he just couldn't stand it, we had to turn it off right away. It was so weird.
My moms cat hates really squeaky voices. And strangely enough, duck calls.
We learned about the duck call from experience, my brother had one that he would mess with just for the fun of it until we noticed that the cat would yowl every time he made a sound with it.