Kenneth - If you are looking for journal studies the best place to start
would be at a university library.  I have been trying to get a study on
mustelids started and in the process I found alot of research on ferrets.
Some of it is research on domesticated ferrets and some of it is on feral
ferrets.  I have come across alot of info on physiology as well as a few
analyses on play behavior, scent marking, and dominance.  I would suggest
using a search on a fisheries and wildlife index under "Mustela" or
"Mustela putorius".  The journals you are likely to find info in are Animal
Behavior, Canadian Journal of Zoology, maybe Journal of Mammalogy.  Kristin
[Posted in FML issue 1275]