Rats are sold at the age they have been weaned and can digest adult foods, around 6 weeks old. They grow very quickly from this stage up until around 14 weeks old. An adult male can be as big as 600g+ and a female 400g+. Rats have been known to live up to 4 years of ages, but the average is 2-3 years of age. A large cage is recommened for them to grow and develop well.
