Q: A question: What are the criteria for deciding if two animals are the same species, separate species or sub-species? Can you clarify this for us? A: And risk being blacklisted by the other magicians for spilling the secret to the trick? Hocus-pocus, alamazoo! Poof! It's a separate species! The idea of species should be a simple concept, after all, everyone can recognize that a ferret is a ferret, a cat is a cat, and a dog is a dog. Recognizing that cats, dogs, and ferrets are separate species has a Duh Factor of 9, but that isn't the problem. The problem isn't figuring out the relationships of distant cousins (unless you live in certain unnamed parts of the USA), but in the relationships of close family relatives. When are red wolves gray wolves, European elk moose, or European red deer elk? Or, in our situation, when are black-footed ferrets polecats, or all polecats one? There are several species concepts in use (biological, nominalist, evolutionary, phylogenetic, recognition, etc.) and they all have their particular strengths and problems. Of all of them, the most widely accepted is the biological species concept, championed by that hotdog of the biological sciences, Ernst Mayr (Oh, I wish I were an Ernst Mayr party liner, that is what I truly want to be, cause if I were an Ernst Mayr party liner, everyone would define species like me!). A species defined under this concept is a natural population of successfully interbreeding individuals that are genetically isolated from other similar populations because of physiological, geographic, or behavioral separation. In this concept, regional groups within the natural population that have substantial differences when compared to the main population- -but that do not remain genetically isolated- -are considered subspecies. This distinction is often quite arbitrary. In any case, part of the problem of subspecies is moot: there are NO currently recognized subspecies of the European polecat. None. Domestic species, such as the ferret, are not governed by the biological species concept (this is why there have been so many problems with how ferrets are named scientifically). Besides the fact that they are under human selection so by definition are not a natural population, drop a dozen ferrets into an area populated with polecats and the ferrets (assuming they can survive) make zero attempt to remain reproductively isolated. Domestic species are not the only types of species the biological concept has problems with; asexual species, because they do not reproduce sexually, do not fit into the concept. It doesn't take a rodent scientist to know domesticated and asexual species are real, but they are not recognized (except superficially) by the biological species concept and even Ernie Mayr can't deny the problems. Defining "isolation" is another problem. Genetic isolation means one group will not make genetic contributions to another group, even if they can breed and produce offspring. You see this with horses and donkeys; they breed, make mules, but the mules are sterile and the two groups are genetically isolated (Frances must have inherited his speaking ability from Ed). In contrast, there are species that range over a wide geographic area where the individuals on the west coast cannot breed successfully with individuals on the east coast, but because they can breed with the neighboring groups and thus maintain genetic contact, they are not considered genetically isolated. Some of these animals have more karyotype differences that the polecats. Where the isolation concept starts to fall apart is when one group is isolated for a period of time, then come back together and breed like teens on beer. At what point is isolation, well, isolation? For example, for some millions of years now the planet has undergone a series of glacial periods interwoven with warm periods. Between the warm and cold periods there is time when species from the Old World can mix with species from the New World. That is why North American elk and European red deer are the same species, wolves are everywhere, and the horse was able to escape North America so the Khan could invigorate things in the Old World. It is also why North America has black-footed ferrets: they were steppe polecats that snuck over to snack on our bountiful prairie dogs. That was probably at least two glacial periods ago because remains of both steppe polecats and BBFs were found from the last interglacial, meaning they were both here at the same time. Now, considering the lack of restraint of male polecats in heat and what they will do to my shoes, there is not a chance in Hades that you can convince me that successful interbreeding didn't take place. Under the biological species concept, this would make the BBF a subspecies of the steppe polecat. How do I know? Because it is true of wolves, caribou/reindeer, elk/red deer, moose/elk, sea otters, wolverine, grizzly bears/brown bears, short-tailed weasels/ermine, and literally scores of other mammalian species, not counting hundreds of avian species. Get the picture? Perhaps the foremost expert on the history of the BBF would be Elaine Anderson, who said (with other experts) about 20 years ago the BBF was a subspecies. So why is it still a distinct species and not a subspecies? Ah, now THAT is the question! Besides the fact that BBFs were so rare you couldn't study them, there is no rule forcing the change, that's why. Changes are done when a scientist decides to do a revision at some basic taxonomic level. There are no computer alerts flashing red when the time has arrived; it is usually done after a few experts bitch and moan, get drunk, and in an alcoholic haze decide they are the best ones to do it. In a revision, all the old stuff is compared with new information, and the revisionists describe what they think are the new proper relationships. Once published and reviewed by other experts in the field, they become the new paradigm and await future revision from other drunken upstarts wanting to build a reputation. And thus science shows you don't have to be sober, you just have to be self-correcting. It is sort of like natural selection, only the best ideas survive at least in the long run. A revision of Mustela is overdue, but why do it now, while the best data is just being generated? Close-up looks at the genome of the Mustelidae, including many members of the genus Mustela, are being done in the USA, Japan, Britain, France, Russia, and other countries. These studies are only now showing up in publications and it is obvious within the next decade there will be numerous others. Any revision of Mustela done before these studies are done could be a waste of time. Personally, I think the biological concept of species is either due for an overhaul, or it is time for a paradigm shift. I think geological time, evolution, and domestic and asexual species HAS to be incorporated into the concept, and the biological species concept ignores all, seeing selected species at a single point in time. For example, ALL species evolve (except extinct species), yet conservation biologists are obsessed with maintaining a genetic status quo in species, which precludes any chance of evolving. Something to think about--extinction through conservation. As for our beloved polecats and ferrets, I have little doubt in my mind that BBFs are a subspecies of the steppe polecat. I am not exactly sure if European and steppe polecats are the same species, but I am sure in the next decade those relationships will be genetically determined. As for the domesticated ferret, I think I would be a fool to pontificate that it was domesticated from ANY polecat, much less any regional variety of polecat. I think the domestication was over a large geographic region, included contributions from both polecats, and since the genetic of polecats is so similar, it will be extremely difficult (or damn lucky) for a domestication origin point to be deduced from the morphology or genetics. Bob C Communications? [log in to unmask] Questions? [log in to unmask] [Posted in FML issue 4570]