To Michele concerning rabies vaccination: Most ferrets, like cats and dogs are vaccinated for rabies about 16 weeks of age. Six months is definitely old enough... Concerning telling ages of ferrets - there is no hard and fast rules. Usually I evaluated tooth wear and tartar buildup, eveluation of eyes, etc, but there are a lot of variables involved here. At best, I can come up with an educated guess...but nothing very scientific in the adults.... Bruce Williams, DVM Department of Veterinary Pathology [log in to unmask] Armed Forces Institute of Pathology (202) 576-2453/2454 Washington, D.C. 20306-6000 [Posted in FML issue 0869]