Q: My one ferret (we have four) Nipper is very quiet most of the time, but when he first gets out of his cage for his daily house romp every hair on his body and tail stands straight up. Is this normal, and what is he trying to say?
A: This is my favorite part of living with ferrets, the bottlebrush tail. An excited, scared or exploring ferret will seem to burst with emotion, and it shows in its tail. The official name for this is piloerection, but ferret owners call it bottlebrush tail because the tail resembles the brush used to clean a bottle. I would describe it as fluffy and prickly as the hair on their tail stands on end.
Unless something is causing your ferret to be nervous or upset, then he is expressing his excitement at being able to explore outside his familiar cage.
Your question made me wonder why excitement or nervousness causes this reaction, after all there doesn’t seem to be a practical reason for it. A ferret with a bottlebrush tail looks larger and animals often attempt to look bigger than they are to scare off a predator. The same reaction that causes the tail hair to stand on end when scared, also causes the same reaction when excited.