The function of a cat's tail:
1. Coordinating body movements and maintaining balance. When cats are walking, running rapidly, chasing prey, or falling from a height, they can use their tails to maintain balance, thus ensuring a safe landing.
2. To express their feelings. Cats can use their tails to convey their emotions and thoughts. For example, when a cat is excited, its tail may twitch and wag violently, while when a cat is fearful or scared, it may lower its tail.
3. A cat's tail helps coordinate its body to complete various movements and physiological behaviors. For example, if a cat wants to jump, it is easy to fall if it does not have the jumping power and support of its tail.
4. When the mother cat walks around with many kittens, her tail stands up high, like a flag, which can serve as a signpost for the kittens.
5. Helps cats swat away flies and mosquitoes. The long tail can act as a fly swatter when the cat is resting on its stomach. 
Important notes about cat tails:
1. A cat's tail is quite dirty, especially near its rear end, where it secretes a lot of oil, making it feel greasy. Therefore, owners can specifically wash their cat's tail.
2. Split ends appear at the tip of the cat's tail. This is one of the signs that a cat is starting to age, but it doesn't mean that all older cats will have this. Some cats will develop bald patches at the tip of their tails as they get older.
3. A cat's tail is an important organ. Never let children lift a cat by its tail, as this can easily injure the cat's tail.
