Re: How to tell how old your hamster is?
It isn't that easy really but a baby hamster up till around 10 weeks tends to have a 'baby' face and also the fur is more wooly and 'matt'. The adult coat is usually there by around 10 weeks. The ears of a young animal up till 4-5months have a very fine downy fur over them and youngsters are more active and busy than a settled older hamster. Adults have bare skin ears.
Size is also a factor as obviously they grow till around 7-8 months, quicker at first then more gradual. Full grown size is very variable and depends on the genetics of the hamster.
There is an increase in pigment and darkness of this on the ears, scent glands and genitals as a hamster gets older too.