I think curious
When a ferret is scared they will have a "bottle brush tail". The fur on their tail will be fluffed up and sticking out.
you have a really messed up enemy.
Cats generally fluff up their tails when they are in a confrontation situation with another cat. You may also notice the fur all over their body fluffing up too. They do this to in an attempt to make themselves look bigger and more dominant - and ready for battle! When the cat is ready to fight you will notice his bristled tail suddenly arching and he may start to growl and appear pretty ferocious. Cats do sometimes fluff up their tail when they are in a playful mood too, but it is quite easy to distinguish between an aggressive fluffed up tail and a playful one by observing the cat's general demeanour, body language and environment.
The same thing it means when you do it.
There are several different reasons why a cat fluffs up his tail. When a cat is in a confrontation situation, he will fluff up his tail - and the fur on his entire body also. What he is in fact doing is trying to make himself look "bigger" in front of his opponent. If a cat's tail is lowered but fluffed up and he is adopting a crouched kind of position, this generally indicates that he is frightened of his opponent and does not want to enter into any kind of confrontation. Sometimes when a cat is in a playful mood he will fluff up his tail, but in this instance you will notice the tail is in an upright position and he generally will not give the appearance of being frightened.
A cat's tail being still can indicate different things depending on the context. It may signal relaxation or attentiveness, while a quivering or puffed-up tail can indicate fear or aggression. It's important to consider the cat's body language as a whole to understand its mood and intentions.
Female cats do not usually pee with their tails up like male cats do. Female cats squat low to the ground when they urinate, while male cats typically lift their tails and spray to mark their territory.
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They fluff up when nervous, scared or excited. Not being fluffed is probably a good thing. Means it is getting used to it's environment.
When cats tails are up that means they're happy. I know because I have one.
If you only see cats with their tails standing up, that is a good sign because it generally indicates a confident and well adjusted animal. A fearful or aggressive cat will hold its tail down, and may lash it from side to side.