A 21-year-old cat is equivalent to a 100-year-old human.

The age comparison table between cats and humans is as follows:

1 and a half months = 4 years old; 3 months = 6 years old; 6 months = 10 years old; 9 months Month = 13 years old; 1 year = 15 years old.

2 years = 24 years old; 3 years = 28 years old; 4 years = 32 years old; 5 years = 36 years old; 6 years = 40 years old.

7 years = 44 years old; 8 years = 48 years old; 9 years = 52 years old; 10 years = 56 years old; 11 years = 60 years old.

12 years = 64 years old; 13 years = 68 years old; 14 years = 72 years old; 15 years = 76 years old; 16 years = 80 years old.

17 years = 84 years old; 18 years = 88 years old; 19 years = 92 years old; 20 years = 96 years old; 21 years = 100 years old.

How to take care of a high-collared cat

Give high-quality, high-protein food specifically for senior cats. Older cats have much higher protein needs than younger and adult cats. In addition to the inevitable aging of the body, illness and stress can also cause a loss of protein stores, thus reducing the body's muscle tissue, and protein supplementation can effectively compensate for these losses.