All of my dogs have been afraid of thunder and loud noises like firecrackers. My cockerspaniel, Ben, used to be afraid of cats -- would cross the street to avoid one -- until he got to know my friend's cats; later in life he lived with four different cats, quite happily. My current dog, Henry, is afraid of stairwells. I can never take the stairs in an apartment building with him, always have to take the elevator.