They are biggest domestic cat breed. That boy you can ssee in my previous message - photographed at the age of 5 months. He is now 7,5 months and I can hardly lift him....But: what a soppy boy! You just look at him and he starts to purr. If properly fed and looked after they will grow the size of ordinary moggy at the age of 4-5 months. They keep to grow till they're 2 years old and another 2 years to mature....