Although BFFs have not been found in California http://www.dfg.ca.gov/hcpb/species/nuis_exo/ferret/fertbiblio.shtml may be what led to the statement. I don't know. One thing I do know is that some sources used by California have been called into question in the past. For instance, I have spoken in the past with a Massachusetts' (If I recall the state properly after all this time -- so people can check the archives) ornithologist who never said that he thought that ferrets could or would destroy shorebird nests, eggs, or chicks. At the time he was still trying to get CA F&G to retract their statement that he had. See: http://www.ohioferret.org/articles/docb.asp?d=24 http://www.dogworldmag.com/ferrets/detail.aspx?aid=25226&cid=3853 but if I recall right (and I may not) there were actual trials to see what could be done if the number went too low to preserve as much of the genetics as possible and they were successful with the Steepe polecat but not the domestic ferret, BUT my memory could be wrong on that score, there could easily have been something new done since i last read on the topic, and it is also possible that if a trial was a small one that the possibility still exists. (Preserving genetics with viable crosses -- and many crosses are not viable within just a few generations -- is a rare but useful approach typically used only in the most dire situations to prevent a complete species loss.) This may help but is old (8 years old): http://www.blackfootedferret.org/research-vargas.html <http://links.jstor.org/sici?sici=0006-3568(199110)41%3A9%3C595%3ARB% 3E2.0.CO%3B2-X> Crosses are also used for essential studies that one would not want to risk a full BFF on such as some found in or at: http://www.jwildlifedis.org/cgi/content/abstract/34/2/362 http://www.ti.org/bffhess.html http://www.jwildlifedis.org/cgi/content/abstract/32/3/417 http://www.r6.fws.gov/feature/ferrets.html -- Sukie (not a vet, and not speaking for any of the below in my private posts) Recommended health resources to help ferrets and the people who love them: Ferret Health List http://www.smartgroups.com/groups/ferrethealth FHL Archives http://ferrethealth.org/archive/ AFIP Ferret Pathology http://www.afip.org/ferrets/index.html Miamiferrets http://www.miamiferret.org/fhc/ International Ferret Congress Critical References http://www.ferretcongress.org [Posted in FML issue 5379]