There are many ways to see how big an American Bobtail cat is, such as:

1. Look at the weight: The smaller the American Bobtail cat is, the lighter it is, and the bigger it is, the heavier it is.

2. Look at the eyes: Young American Bobtails have clear eyes, while older American Bobtails have cloudy eyes.

3. Look at the fur: the younger the American Bobtail is The smoother the cat's fur, the rougher the fur of the larger American Bobtail, and the whiter the face of the older American Bobtail.

4. Look at the teeth: 2-4 perimeter first teeth, 4-6 perimeter premolars. Around 4 months of age, the deciduous teeth grow together, there are 26 teeth in total, and the teeth begin to be replaced around 5 months of age. A 1-year-old adult American Bobtail cat has 30 permanent teeth.