Rats grow rapidly until they reach 12-14 weeks. After this, the growth slows down but they continue to fill out until they reach six months of age. Adult males usually weigh 400-700g, females around 200-500g. As long as a rat has been handled as a youngster, it will bond to you no matter how old it is when you first get it.

Rats usually live for around two years, although some make it to three and beyond. A big cage, other rats for company, a healthy diet, and lots of exercise is the best way of making sure that your rats have a long, happy life.

Rats are highly intelligent, social animals, and although they enjoy the companionship of humans, they thrive in - and need - the company of their own species. Although they will usually survive if kept as single pets, pet care is not just a matter of keeping animals alive; rats will have happier and more interesting lives when kept with other rats. Rats should never live alone, and ideally should be kept in groups of two or more of the same sex.

Rats enjoy grooming each other, curling up to sleep together, and sometimes even fighting. It is usual for rats to scrap occasionally, do not worry about this unless you see serious injuries.