try and give you a sencible answer pal .. if they see the moon big and bright in the night sky , its something unusualll for them ,, so they howl , daytime . /and night this may sound soft .. but it may have something to do with a change in gravitational pull ..as in the tides maybe dogs sence it .. probebly just writen aload of crap but i did try ..lol
Thats what i would have assumed
Isnt there people called lunatics.They kick off when the moon is full.