A chubby cat doesn't refer to a specific breed, as cats of different breeds can become obese due to genetics, diet, or lack of exercise. However, some breeds are more prone to appearing rounder and fuller due to their genetic characteristics and body type. For example, Persian, British Shorthair, Maine Coon, and Ragdoll cats are typically larger with thicker frames, and are more susceptible to obesity if not properly cared for.

To determine if a cat belongs to a specific breed, you need to consider its physical characteristics, such as facial structure, coat texture and color, body proportions, and whether it has breed standard certification. To find out a cat's exact breed, consult a professional veterinarian or cat breeder.