There's this dog somewhere nearby (I don't know where exactly) that's been making noises pretty much all day yesterday, today and overnight. It barks or howls (in particular it seems to howl a lot) every 20 seconds or so. Now, in all likelihood it'll have stopped by tomorrow, but I've never heard anything like it in the past despite the fact that there are several dogs living in the area. My understanding of dog behaviour is essentially limited to "if it wags its tail, it's happy", so I don't know why it's suddenly acting this way. It's definitely just the one dog, not one of those instances where one dog starts yapping and all the others join in. Does it sound as though it could be in distress, and if so, are there any warning signs I should be looking out for?