The meaning of a cat's tail is:
"Qilin-tailed cats" refers to a type of cat born with a congenital tail deformity. Through generations of breeding, this mutated gene has gradually become a stable, normal gene. These cats are born with exceptionally short or curved tails, and are commonly referred to as "Qilin-tailed cats" in folk parlance. 
Characteristics of a cat's unicorn tail:
The short, curved tail is generally referred to as a "Qilin tail." The Qilin tail is a distinctive feature of the Qilin cat, a shape that gradually became fixed due to a genetic mutation and through generations of breeding. Researchers at the School of Life Sciences, Peking University, including Luo Shujin and his team, discovered that a gene mutation called T-box causes the Manx cat's short tail. Subsequent research found that the T-box gene mutation is unrelated to the Japanese Bobtail, indicating that other genes determine tail length.
