Okay - this is about all i know on the tattoo issue... Marshall Farms tattoos their ferrets in the RIGHT ear with two dots which look black and then turn blue as the ferret grows. Since the ear is pulled out and away from the ferret to ID it, sometimes the second dot is actually on the head near the ear or it might be so close to the tip that it mioght not bee seen. The ONLY ferrets tattooed with one dot by Marshall farms are males that have been neutered but not descented - usually lab animals. Marshall Farms does not release intact females at any time. The MI / Ohio area has some vet and backyard breeders marking their ferrets in the LEFT ears with two dot tattoos. this is supposed to mark the ferrets already neutered and descented, but there have been a few reports of intact ferrets being marked this way and still have a tattoo. Ferrets from Manitoba, Canada are marked in the right ear with a letter - looks like it is done by hand and many times it is hard to figure out what the letter is. I have seen X, L, T and Z. There are reports of ferrets being marked with double dot tattoos which are NOT from Marshall Farms - anytime you buy a ferret in a pet shop, you should ask to see the shipping invoice to see where they came from if it really matters to you. Marshall Farms sell direct, with the exception of Denver Ferrets and maybe a place in FL. Hope this helps. Pam / STAR* [Posted in FML issue 1425]